Prenatal Care and Adaptations to Pregnancy PDF

Prenatal Care and Adaptations to Pregnancy OBJECTIVES 1. Define each key term listed. 2. List the goals of prenatal care. 3. Discuss prenatal care for a normal pregnancy. 4. Explain the nurse’s role in prenatal care. 5. Calculate the expected date of delivery and duration of pregnancy. 6. Differenti...

Prenatal Care and Adaptations to Pregnancy OBJECTIVES 1. Define each key term listed. 2. List the goals of prenatal care. 3. Discuss prenatal care for a normal pregnancy. 4. Explain the nurse’s role in prenatal care. 5. Calculate the expected date of delivery and duration of pregnancy. 6. Differentiate among the presumptive, probable, and positive signs of pregnancy. 7. Describe the physiological changes that occur during pregnancy. 8. Identify nutritional needs for pregnancy and lactation. 9. Discuss the importance and limitations of exercise in pregnancy. 10. Describe patient education related to travel and common discomforts of pregnancy. 11. Discuss nursing support for emotional changes that occur in a family during pregnancy. 12. Identify special needs of the pregnant adolescent, the single parent, and the older couple. 13. Apply the nursing process in developing a birth plan. 14. Identify the effects of medication ingestion on pregnancy and lactation. 15. Review immunization administration during pregnancy. KEY TERMS abortion (p. 51) antepartum (p. 47) aortocaval compression (a-ŏr-tō-KĀ-văl kŏm-PRĔSH-ŭn, p. 57) birth plan (p. 76) Braxton Hicks contractions (p. 53) Chadwick’s sign (p. 53) chloasma (p. 53) colostrum (kŏ-LŎS-trŭm, p. 56) estimated date of delivery (EDD) (p. 49) gestational age (p. 51) Goodell’s sign (p. 53) gravida (GRĂV-ĭ-dă, p. 51) Hegar’s sign (p. 53) intrapartum (p. 47) lactation (lăk-TĀ-shŭn, p. 56) 128 last normal menstrual period (LNMP) (p. 48) lightening (p. 57) McDonald’s sign (p. 53) Multipara (mŭl-TĬP-ă-ră, p. 51) Nägele’s rule (NĀ-gĕ-lēz rūl, p. 52) para (PĂR-ă, p. 51) postpartum (p. 47) primigravida (prĭ-mĭ-GRĂV-ĭ-dă, p. 51) primipara (prĭ-MĬP-ă-ră, p. 51) pseudoanemia (sū-dō-ă-NĒ-mē-ă, p. 57) quickening (p. 53) supine hypotension syndrome (p. 57) trimesters (p. 52) http://evolve.elsevier.com/Leifer Pregnancy is a temporary, physiological (that is, normal) process that affects a woman physically and emotionally. All systems of her body adapt to support the developing fetus. There are three phases of pregnancy: antepartum or prenatal (before birth), intrapartum (during birth), and postpartum (after birth). The focus of nursing care during pregnancy is to teach the mother how to maintain good health or, in the case of a mother with a condition that places her or her fetus at risk, to improve her health as much as possible to promote a healthy outcome for both mother and fetus. Good prenatal care can also help prevent adult-onset diseases in the infant. This chapter reviews prenatal care, the physiological and psychological changes of pregnancy, and nursing care to meet the needs of women and families. 129 Goals of prenatal care Prenatal care is a primary example of preventive medicine. Early and regular prenatal care is the best way to ensure a healthy outcome for both mother and child. Obstetricians, family practice physicians, certified nurse-midwives, and nurse practitioners provide prenatal care. The nurse assists the health care provider in evaluating the expectant family’s physical, psychological, and social needs and teaches the woman self-care. The major goals of prenatal care are as follows: • Promote the health of the mother, fetus, newborn, and family. • Ensure a safe birth for mother and child by promoting good health habits and reducing risk factors. • Teach health habits that may be continued after pregnancy. • Educate in self-care for pregnancy. • Develop a partnership with parents and family to provide continuous and coordinated health care. • Provide physical care. • Prepare parents for the responsibilities of parenthood. To achieve these goals, health care providers must do more than offer physical care. Health care providers must work as an interprofessional team to create an environment that allows for cultural and individual differences, while being supportive of the entire family. Nursing Tip The major roles of the nurse during prenatal care include collecting data from the pregnant woman, identifying and reevaluating risk factors, educating in self-care, providing nutrition counseling, and promoting the family’s adaptation to pregnancy. Legal and Ethical Considerations Documenting abnormal data such as high blood pressure must be followed by documentation of intervention or referral for follow-up care. 130 Preconception care Recent studies have revealed that prenatal influences have a long-term effect on the adult health of the newborn infant. During pregnancy, maternal diet, exercise, smoking, stress, drugs, and environmental pollutants can affect the adult health of the developing fetus; therefore the current goal of prenatal care is no longer limited to the outcome of a healthy mother and newborn, but is expanded to the prevention of adult disease in the newborn infant. This expanded focus may result in reduction of noncommunicable diseases in developed and underdeveloped countries and have an impact on global health. At the 2017 International Meeting for Autism Research, discussion included a study that examined how smoking during pregnancy may affect the developing eggs of a female fetus, which may affect the grandchildren of the smoker, especially related to autism spectrum disorder. Pregnancy wellness begins before conception occurs (Afshar and Hans, 2017). Preconception care involves a discussion of pregnancy intention, access to care, use of multivitamins and folic acid, smoking, sexually transmitted infections, illicit drug use, and mental health issues. Education related to healthy weight and glycemic control, use of teratogenic medications, and discussion of family history and chronic illness should also be provided. Interview forms are available to use as a guide from http://www.marchofdimes.org/pregnancy/your-checkup-before-pregnancy.aspx. Optimal obstetric care includes the following: • Preconception care: Includes preparation for the impact the newborn will have on family dynamics and preparation and follow-up of the preconception interview. • Prenatal care: Involves the monitoring, care, and management of issues arising during pregnancy. • Intrapartum care: Involves the continuous presence and support of the parents by a labor and delivery nurse or doula during the birth process. • Postpartum care: Involves supporting the adjustment after birth including encouragement to breast feed, skin-to-skin contact, and bonding while reducing separations and interruptions. Early discharge to a busy household can interfere in mother–infant bonding in early postpartum days. Follow-up care of mother and infant is important. 131 Prenatal visits Ideally health care for childbearing begins before conception. Preconception care identifies risk factors that may be changed before conception to reduce their negative impact on the outcome of pregnancy. For example, the woman may be counseled about how to improve her nutritional state before pregnancy or may receive immunizations to prevent infections that would be harmful to the developing fetus. An adequate folic acid intake before conception can reduce the incidence of congenital anomalies (see Chapter 14). Some risk factors cannot be eliminated, such as preexisting diabetes, but preconception care helps the woman to begin pregnancy in the best possible state of health. Prenatal care should begin, if not before conception, as soon as a woman suspects that she is pregnant. A complete history and physical examination will help identify problems that may affect the woman or her fetus. The history should include the following: • Obstetric history: Number and outcomes of past pregnancies; problems in the mother or infant • Menstrual history: Usual frequency of menstrual cycles and duration of flow; first day of the last normal menstrual period (LNMP); any “spotting” since LNMP • Contraceptive history: Type used; whether an oral contraceptive was taken before the woman realized she might be pregnant; whether an intrauterine device is still in place • Medical and surgical history: Infections such as hepatitis or pyelonephritis; surgical procedures; trauma that involved the pelvis or reproductive organs • Family history of the woman and her partner: To identify genetic or other factors that may pose a risk for the pregnancy • Health history of the woman and her partner: To identify risk factors (e.g., genetic defects or use of alcohol, drugs, or tobacco) and possible blood incompatibility between the mother and the fetus • Psychosocial history of the woman and her partner: To identify stability of lifestyle and ability to parent a child; significant cultural practices or health beliefs that may affect the pregnancy The woman has a complete physical examination on her first visit to evaluate her general health, determine her baseline weight and vital signs, evaluate her nutritional status, and identify current physical or social problems. A pelvic examination is performed to evaluate the size, adequacy, and condition of the pelvis and reproductive organs and to assess for signs of pregnancy (see Box 4.3). Health Promotion Optimal prenatal care uses a “teachable moment” to introduce knowledge and lifelong skills in self-care and wellness that includes continuing health care screening, immunizations, and regular follow-up of all risk factors throughout life for each member of the family. The woman’s estimated date of delivery (EDD) is calculated based on LNMP. An ultrasound examination may be done at this visit or at a later visit to confirm EDD. An assessment for risk factors that may affect the pregnancy is performed during the first visit and is updated at subsequent visits. Several routine laboratory tests are performed on the first or the second prenatal visit. Others are done at specific times during pregnancy and may be repeated at certain intervals. Several tests are done for all pregnant women; others are based on the presence of various risk factors. The U.S. Preventive Services Task Force recommends obtaining urine cultures at 12 to 16 weeks gestation to screen for asymptomatic bacteriuria. Early treatment of this condition can prevent preterm births. The 2011 American College of Obstetricians and Gynecologists (ACOG) guidelines recommend a vaginal and rectal swab be done to detect group B streptococcus at 35 to 37 weeks gestation to protect mother and infant from infection during labor and birth (Gregory, 2017). Table 4.1 lists 132 prenatal laboratory tests. To prevent unnecessary fears or stress, it is important that the nurse explain that most tests are used to establish a baseline normal for comparison throughout pregnancy. Table 4.1 Routine Prenatal Testsa ACOG, American College of Obstetricians and Gynecologists; CBC, complete blood count; EDD, estimated date of delivery; HIV, human immunodeficiency virus; NTT, nuchal translucency test; PPD, purified protein derivative; RPR, rapid plasma reagin; STIs, sexually transmitted infections; VDRL, Venereal Disease Research Laboratory (test). a Additional optional prenatal diagnostic tests are described in Table 5.1. Data from American College of Obstetricians and Gynecologists: Guidelines for perinatal care, 7th ed, Washington, DC, 2012, American College of Obstetricians and Gynecologists. The development of human genome mapping has expanded the prenatal detection of genetic disorders and provides the basis for future therapeutic interventions. The future direction of prenatal testing is to provide early, accurate, noninvasive screening tests. The recommended schedule for prenatal visits in an uncomplicated pregnancy is as follows: • Conception to 28 weeks—every 4 weeks • 29 to 36 weeks—every 2 to 3 weeks • 37 weeks to birth—weekly 133 Safety Alert! Early and regular prenatal care is important for reducing the number of low-birth-weight infants and for reducing morbidity and mortality for mothers and newborns. The pregnant woman is seen more often if complications arise. Routine assessments made at each prenatal visit include the following: • Review of known risk factors and assessment for new ones. • Vital signs: The woman’s blood pressure should be taken in the same arm and in the same position (horizontal and at heart level) each time for accurate comparison with her baseline value. • Weight to determine if the pattern of gain is normal: Low prepregnancy weight or inadequate gains are risk factors for preterm birth, a low-birth-weight infant, and other problems. A sudden, rapid weight gain is often associated with gestational hypertension. • Urinalysis for protein, glucose, and ketone levels. • Blood glucose screening between 24 and 28 weeks gestation: Additional testing is done if the result of this screening test is abnormal. • Hematocrit, group B streptococcus, and sexually transmitted infection testing may also be performed at 36 weeks gestation. • Fundal height to determine if the fetus is growing as expected and the volume of amniotic fluid is appropriate (see Fig. 4.3). • Leopold’s maneuvers to assess the presentation and position of the fetus by abdominal palpation (usually at about 36 weeks gestation). • Fetal heart rate: During very early pregnancy, the fetal heart rate is measured with a Doppler transducer; in later pregnancy, it may also be heard with a fetoscope. Beating of the fetal heart can be seen on ultrasound examination 8 weeks after LNMP. • Fetal activity (“kick count”) assessment may be done at 28 weeks and repeated as needed (see Chapter 5). • Review of nutrition for adequacy of calorie intake and specific nutrients. • Discomforts or problems that have arisen since the last visit. Nursing Tip The nurse listens to concerns and answers questions from the expectant family during each prenatal visit. This is a prime time for teaching good health habits because most women are highly motivated during pregnancy to improve their health. The nurse establishes rapport with the expectant family by conveying interest in their needs, listening to their concerns, and directing them to appropriate resources. The health care team must show sensitivity to the family’s cultural and health beliefs and incorporate as many as possible into care. For example, Muslim laws of modesty dictate that a woman be covered (hair, body, arms, and legs) when in the presence of an unrelated man, and therefore a female health care provider is often preferred. Latino families expect a brief period of conversation during which pleasantries are exchanged before “getting to the point” of the visit. An Asian woman may nod her head when the nurse teaches her, leading the nurse to believe that she understands and will use the teaching. However, the woman may be showing respect to the nurse rather than agreement with what is taught. Eye contact, which is valued by many Americans, is seen as confrontational in some cultures. 134 Virtual prenatal care The practice of using technology to reduce health care costs has spawned the practice of virtual prenatal visits or group prenatal visits, which replace some “in person” individual prenatal visits. A nurse practitioner completes a prenatal visit by videoconferencing. Group or virtual prenatal visits increase patient satisfaction and may lower costs (Manzoni and Carter, 2017). Before the virtual visits, the nurse should confirm that any required consent forms have been completed, signed, and dated. The practice of virtual prenatal care may be suitable for low-risk patients but should not be used for moderate-risk or high-risk patients who should have blood pressure or other in-person assessments monitored more closely during each visit (Flug et al, 2015). 135 Definition of terms The following terms are used to describe a woman’s obstetric history: • Gravida: Any pregnancy, regardless of duration; also, the number of pregnancies including the one in progress. • Nulligravida: A woman who has never been pregnant. • Primigravida: A woman who is pregnant for the first time. • Multigravida: A woman who has been pregnant before, regardless of the duration of the pregnancy. • Para: A woman who has given birth to one or more children who reached the age of viability (20 weeks gestation), regardless of the number of fetuses delivered and regardless of whether those children are now living. • Primipara: A woman who has given birth to her first child (past the point of viability), regardless of whether the child was alive at birth or is now living. The term is also used informally to describe a woman before the birth of her first child. • Multipara: A woman who has given birth to two or more children (past the point of viability), regardless of whether the children were alive at birth or are presently alive. The term is also used informally to describe a woman before the birth of her second child. • Nullipara: A woman who has not given birth to a child who reached the point of viability. • Abortion: Termination of pregnancy before viability (20 weeks gestation), either spontaneous or induced. • Gestational age: Prenatal age of the developing fetus calculated from the first day of the woman’s LNMP. • Fertilization age: Prenatal age of the developing fetus as calculated from the date of conception; approximately 2 weeks less than the gestational age. • Age of viability: A fetus that has reached the stage (usually at 20 weeks) where it is capable of living outside of the uterus. The word gravida indicates the number of pregnancies. The word para indicates the outcome of the pregnancies. The gravida number increases by 1 each time a woman is pregnant, whereas the para number increases only when a woman delivers a fetus of at least 20 weeks gestation. For example, a woman who has had two spontaneous abortions (miscarriages) at 12 weeks gestation, has a 3-year-old son, and is now 32 weeks pregnant would be described as gravida 4, para 1, abortions 2. The TPALM system (Box 4.1) is a standardized way to describe the detailed outcomes of a woman’s pregnancies on her prenatal record. Box 4.1 TPALM System to Describe Parity T P A L M Number of term infants born (infants born after at least 37 weeks gestation) Number of preterm infants born (infants born after 20 weeks or before 37 weeks gestation) Number of pregnancies aborted before 20 weeks gestation (spontaneously or induced) Number of children now living Multiple birth number of multiple gestations (optional) Example Katie Field: Gravida 3, TPALM (para) 10110. Anna Luz: Gravida 4, TPALM (para) 11120. 136 137 Determining the estimated date of delivery The average duration of a term pregnancy is 40 weeks (280 days) after the first day of the LNMP. Nägele’s rule is used to determine EDD. To calculate EDD, one identifies the first day of LNMP, counts backward 3 months, and then adds 7 days (Box 4.2). The year is updated if applicable. EDD is an estimated date, and many normal births occur before or after this date. EDD may also be determined with a gestation wheel, an electronic calculator designed for this purpose, a physical examination, an ultrasound, or a combination of these methods. Box 4.2 Nägele’s Rule to Determine Estimated Date of Delivery 1. 2. 3. 4. Determine first day of last normal menstrual period (LNMP) Count backward 3 months Add 7 days Correct the year if necessary Example 1. First day of LNMP: January 27 2. Count backward 3 months: October 27 3. Add 7 days: November 3 is estimated date of delivery (EDD) Guidelines concerning methods to estimate the due date by ACOG and the American Institute of Ultrasound and the Maternal-Fetal Society include: • The LMNP plus 280 days • Using Nägele’s rule • If the LMNP is unknown, or the abdominal ultrasound in the first trimester differs from Nägele’s calculation by more than 5 days, a crown-rump length on ultrasound can be used to determine EDD. An abdominal ultrasound after 14 weeks gestation can use the biparietal diameter, head circumference, abdominal circumference, and femur length to confirm EDD (Wisner, 2016). Pregnancy is divided into three 13-week parts called trimesters. Predictable changes occur in the woman and the fetus in each trimester. Understanding these developments helps to better provide anticipatory guidance and identify deviations from the expected pattern of development. 138 Diagnosis of pregnancy The signs of pregnancy are divided into three general groups: presumptive, probable, and positive, depending on how likely they are to be caused by factors other than pregnancy (Box 4.3). Box 4.3 Signs of Pregnancy Presumptive  Amenorrhea  Nausea  Breast tenderness  Deepening pigmentation  Urinary frequency  Quickening Probable  Goodell’s sign  Chadwick’s sign  Hegar’s sign  McDonald’s sign  Abdominal enlargement  Braxton Hicks contractions  Ballottement  Striae  Positive pregnancy test Positive  Audible fetal heartbeat  Fetal movement felt by examiner  Ultrasound visualization of fetus Presumptive Signs of Pregnancy The presumptive indications of pregnancy are those from which a definite diagnosis of pregnancy cannot be made. These signs and symptoms are common during pregnancy but can often be caused by other conditions. Amenorrhea, the cessation of menses, in a healthy and sexually active woman is often the first sign of pregnancy. However, strenuous exercise, changes in metabolism and endocrine dysfunction, chronic disease, certain medications, anorexia nervosa, early menopause, or serious psychological disturbances may also be the cause. Nausea and sometimes vomiting occur in at least half of all pregnancies; it may be the result of an increase of human chorionic gonadotropin (hCG) levels in early pregnancy and is not associated with unfavorable outcomes for mother or infant (Gabbe, 2017). “Morning sickness” describes the symptoms, but they may occur at any time of day. Distaste for certain foods or even their odors may be the main complaint. The nausea begins about 4 weeks after the LNMP and usually improves by the end of the 20th week. By screening the woman for nausea and vomiting during 139 prenatal visits, the nurse can offer interventions and supportive care that can increase the quality of the pregnancy experience. Emotional problems or gastrointestinal upsets may also cause nausea and vomiting. When diet and lifestyle changes do not relieve morning sickness, Diclegis (doxylamine and pyridoxine) may be prescribed by the health care provider. Diclegis is an extended-release tablet that is administered at bedtime. A side effect may be drowsiness. The medication is not recommended for breastfeeding mothers. Breast changes include tenderness and tingling as hormones from the placenta stimulate growth of the ductal system in preparation for breastfeeding. Similar breast changes also occur premenstrually in many women. Striae are pink-to-brown lines that may develop as the breasts enlarge (Fig. 4.1). FIG. 4.1 Striae and pigmentation of breasts. Note the darkened pigmentation of areolae and the pinkwhite lines at the base of the breasts that are caused by stretching of the elastic tissue as the breasts enlarge. Pigmentation will disappear after pregnancy, and striae will fade into silvery strands. (From Swartz MH: Textbook of physical diagnosis: history and examination, ed 7, Philadelphia, 2014, Saunders.) Pigmentation changes occur primarily in dark-skinned women. Common skin changes of pregnancy include increased pigmentation of the face (chloasma, or “mask of pregnancy”), breasts (darkening of the areolae), and abdomen (linea nigra, a line extending in the midline of the abdomen from just above the umbilicus to the symphysis pubis) (Fig. 4.2). 140 FIG. 4.2 Abdominal striae are pinkish white or purple-gray lines that may occur in pregnancy. They may be found on the breasts, abdomen, and thighs. The dark line at the midline is the linea nigra, an area of increased pigmentation most noticeable in dark-skinned women. Frequency and urgency of urination are common in the early months of pregnancy. The enlarging uterus, along with the increased blood supply to the pelvic area, exerts pressure on the bladder. Urinary frequency occurs in the first trimester until the uterus expands and becomes an abdominal organ in the second trimester. The pregnant woman experiences frequency of urination again in the third trimester when the presenting part descends in the pelvis in preparation for birth. Causes of urinary disturbances other than pregnancy are urinary tract infections and pelvic masses. Fatigue and drowsiness are early symptoms of pregnancy. It is believed that fatigue is caused by increased metabolic needs of the woman and fetus. In an otherwise healthy young woman, it is a significant sign of pregnancy. However, illness, stress, or sudden changes in lifestyle may also cause fatigue. Quickening, fetal movement felt by the mother, is first perceived at 16 to 20 weeks of gestation as a faint fluttering in the lower abdomen. Women who have previously given birth often report quickening at an earlier stage because they know how to identify it. This is an important event to record because it marks the approximate midpoint of the pregnancy and is another reference point to verify gestational age. Abdominal gas, normal bowel activity, or false pregnancy (pseudocyesis) are other possible causes of this fluttering in the lower abdomen. Probable signs of pregnancy The probable indications of pregnancy provide stronger evidence of pregnancy. However, these also may be caused by other conditions. 141 Goodell’s sign is the softening of the cervix and the vagina caused by increased vascular congestion. Chadwick’s sign is the purplish or bluish discoloration of the cervix, vagina, and vulva caused by increased vascular congestion. Hormonal imbalance or infection may also cause both Goodell’s and Chadwick’s signs. Hegar’s sign is a softening of the lower uterine segment. Because of the softening, it is easy to flex the body of the uterus against the cervix, which is known as McDonald’s sign. Abdominal and uterine enlargement occurs irregularly at the onset of pregnancy. By the end of the 12th week, the uterine fundus may be felt just above the symphysis pubis, and it extends to the umbilicus between 20 and 22 weeks (Fig. 4.3). Uterine or abdominal tumors may also cause enlargement. FIG. 4.3 Height of fundus during gestation. (A) The numbers represent the weeks of gestation, and the circles represent the height of the fundus expected at that stage of gestation. Note: The 40th week is represented by a dotted line to indicate lightening has occurred. (B) A health care provider measures the height of the fundus during a clinic visit. (A from Murray SS, McKinney ES, Gorrie TM: Foundations of maternal-newborn nursing, ed 2, Philadelphia, 1998, Saunders. B courtesy Pat Spier, RN-C.) Braxton Hicks contractions are irregular, painless uterine contractions that begin in the second trimester. These contractions give the sensation of the abdomen being hard and tense. They become progressively more noticeable as term approaches and are more pronounced in multiparas. They may become strong enough to be mistaken for true labor. Uterine fibroids (benign tumors) may also cause these contractions. Ballottement is a maneuver by which the fetal part is displaced by a light tap of the examining finger on the cervix, and then the part rebounds quickly. Uterine or cervical polyps (small tumors) may cause the sensation of ballottement on the examiner’s finger. Fetal outline may be identified by palpation after the 24th week. It is possible to mistake a tumor for a fetus. Abdominal striae (stretch marks) are fine, pinkish white or purplish gray lines that some women develop when the elastic tissue of the skin has been stretched to its capacity (see Fig. 4.2). Increased amounts of estrogen cause an increase in adrenal gland activity. This change, in addition to the stretching, is believed to cause breakdown and atrophy of the underlying connective tissue in the skin. Striae are seen on the breasts, thighs, abdomen, and buttocks. After pregnancy, the striae lose their bright color, and they become thin, silvery lines. Striae may occur with skin stretching from any cause, such as weight gain. Pregnancy tests use maternal urine or blood to determine the presence of hCG, a hormone produced by the chorionic villi of the placenta. Home pregnancy tests based on the presence of hCG in the urine are capable of greater than 97% accuracy, but the instructions must be followed precisely 142 to obtain this accuracy. Professional pregnancy tests are based on urine or blood serum levels of hCG, and they are more accurate. A highly reliable pregnancy test is the radioimmunoassay. The radioimmunoassay is a blood test that accurately identifies pregnancy 1 week after ovulation. Pregnancy tests of all types are probable indicators because several factors may interfere with their accuracy, including medications such as antianxiety or anticonvulsant drugs, blood in the urine, malignant tumors, or premature menopause. Positive signs of pregnancy Only a developing fetus causes positive signs of pregnancy. These include demonstration of fetal heart activity, fetal movements felt by an examiner, and visualization of the fetus with ultrasound. Fetal heartbeat may be detected by 10 weeks gestation by using a Doppler device. The examiner can detect the fetal heartbeat using a fetoscope between 18 and 20 weeks of pregnancy. When the fetal heartbeat is heard with a fetoscope, this is important because it provides another marker of the approximate midpoint of gestation. When assessing the fetal heartbeat with a Doppler device or fetoscope, the woman’s pulse rate must be assessed at the same time to be certain that the fetal heart is what is actually heard. The fetal heart rate at term ranges between a low of 110 to 120 beats/min and a high of 150 to 160 beats/min. The rate is higher in early gestation and slows as term approaches. Additional sounds that may be heard while assessing the fetal heartbeat are the uterine and funic souffles. Uterine souffle is a soft blowing sound heard over the uterus during auscultation. The sound is synchronous with the mother’s pulse and is caused by blood entering the dilated arteries of the uterus. The funic souffle is a soft swishing sound heard as the blood passes through the umbilical cord vessels. A trained examiner can feel fetal movements in the second trimester. The examiner must distinguish fetal activity because, to a prospective mother, normal intestinal movements can appear similar to the faint fetal movements typical of early pregnancy. Fetal movements can be seen with ultrasound. Identification of the embryo or fetus by means of ultrasound photography of the gestational sac is possible at 4 to 5 weeks gestation with 100% reliability. This noninvasive method is the earliest positive sign of a pregnancy. An ultrasound is often routinely performed around 20 weeks gestation (Fig. 4.4). 143 FIG. 4.4 The pregnant woman’s family may be present during an ultrasound. 144 Physiological changes in pregnancy The woman’s body undergoes dramatic changes as she houses and nourishes her growing child. Most of these changes reverse shortly after birth. Role of microbiomes in pregnancy The physiological changes in the body that occur during pregnancy involve every organ system in the body of the mother. Recent research has revealed that the microbiome (the normal microbes in the individual’s own body) also play a role in maintaining pregnancy, preparation for labor, and establishing a microbiome that is passed on to the newborn. For example, these microbiomes contribute to development of the acidic vaginal changes that occur during pregnancy that protect the woman from vaginal infections and may play a role in preventing preterm births. Research has shown that the microbes in the oral cavity of the mother are spread by the blood to the placenta, which explains the relationship between periodontal (dental) disease and preterm birth, owing to the influence of placental functions (Antony et al, 2017). The microbiomes in the breast milk of mothers also contribute to the establishment of a gut microbiome in the newborn infant after birth and is important in the health of the infant as he or she grows and develops (Zegaric, 2017). Endocrine system Hormones are essential to maintain pregnancy, and the dramatic increase in hormones during pregnancy affects all body systems. Most hormones are produced by the corpus luteum initially and later by the placenta. The most striking change in the endocrine system during pregnancy is the addition of the placenta as a temporary endocrine organ that produces large amounts of estrogen and progesterone to maintain the pregnancy (as well as hCG and human placental lactogen [hPL]). hPL increases maternal insulin resistance during pregnancy, providing the fetus with glucose needed for growth (Table 4.2). Table 4.2 Hormones Essential in Pregnancy Hormone Estrogen Progesterone T4 hCG hPL (also called chorionic somatomammotropin) MSH Relaxin Prolactin Oxytocin Source and significance Produced by ovaries and placenta Responsible for enlargement of uterus, breasts, and genitals Promotes fat deposit changes Stimulates MSH in hyperpigmentation of skin Promotes vascular changes Promotes development of striae gravidarum Alters sodium and water retention Produced by corpus luteum and ovary and later by placenta Maintains endometrium for implantation Inhibits uterine contractility, preventing abortion Promotes development of secretory ducts of breasts for lactation Stimulates sodium secretion Reduces smooth muscle tone (causing constipation, heartburn, varicosities) Influences thyroid gland size and activity and increases heart rate Increases basal metabolic rate 23% during pregnancy Produced early in pregnancy by trophoblastic tissue Stimulates progesterone and estrogen by corpus luteum to maintain pregnancy until placenta takes over Used in pregnancy tests to determine pregnancy state Produced by placenta Affects glucose and protein metabolism Has a diabetogenic effect—allows increased glucose to stimulate pancreas and increase insulin level Produced by anterior pituitary gland Causes pigmentation of skin to darken, resulting in brown patches on face (chloasma [melasma gravidarum]), dark line on abdomen (linea nigra), darkening of moles and freckles, and darkening of nipples and areolae Produced by corpus luteum and placenta Remodels collagen, causing connective tissue of symphysis pubis to be more movable and cervix to soften Inhibits uterine activity Prepares breasts for lactation Produced by posterior pituitary gland 145 Stimulates uterine contraction Is inhibited by progesterone during pregnancy After birth, helps keep uterus contracted Stimulates milk ejection reflex during breastfeeding hCG, Human chorionic gonadotropin; hPL, human placental lactogen; MSH, melanocyte-stimulating hormone; T4, thyroxine. Reproductive system Uterus The uterus undergoes the most obvious changes in pregnancy. Before pregnancy, the uterus is a small, muscular, pear-shaped pelvic organ that weighs about 60 g (2 oz), measures 7.5 cm (3 inches) long × 5 cm (2 inches) wide × 1 to 2.5 cm (0.4 to 1 inch) deep, and has a capacity of about 10 mL (⅓ oz). The uterus expands gradually during pregnancy by increasing both the number of myometrial (muscle) cells during the first trimester and the size of individual cells during the second and third trimesters. The uterus becomes a temporary abdominal organ at the end of the first trimester. At term, the uterus reaches the woman’s xiphoid process and weighs about 1000 g (2.2 lb). Its capacity is about 5000 mL (5 quarts), enough to house the term fetus, placenta, and amniotic fluid. Cervix Soon after conception, the cervix changes in color and consistency. Chadwick’s and Goodell’s signs appear. The glands of the cervical mucosa increase in number and activity. Secretion of thick mucus leads to the formation of a mucous plug that seals the cervical canal. The mucous plug prevents the ascent of vaginal organisms into the uterus. With the beginning of cervical thinning (effacement) and opening (dilation) near the onset of labor, the plug is loosened and expelled. Ovaries The ovaries do not produce ova (eggs) during pregnancy. The corpus luteum (empty graafian follicle) (see Chapter 2) remains on the ovary and produces progesterone to maintain the decidua (uterine lining) during the first 6 to 7 weeks of the pregnancy until the placenta can perform this function. Vagina The vaginal blood supply increases, causing the bluish color of Chadwick’s sign. The vaginal mucosa thickens, and rugae (ridges) become prominent. The connective tissue softens to prepare for distention as the child is born. Vaginal secretions increase. In addition, the vaginal pH becomes more acidic to protect the vagina and uterus from pathogenic microorganisms. However, the vaginal secretions also have higher levels of glycogen, a substance that promotes the growth of Candida albicans, the organism that causes yeast infections. The most common cause of vaginal discharge is bacterial vaginosis, in which there is a decrease in normal lactobacilli and an increase in bacteroids and other anaerobic microorganisms. There may be a milky white vaginal discharge, but often there are no other clinical symptoms. Bacterial vaginosis has been associated with preterm labor, and many obstetricians routinely screen pregnant women for bacterial vaginosis early in pregnancy. Treatment with antimicrobials between 12 and 20 weeks gestation is common. Breasts Hormone-induced breast changes occur early in pregnancy. High levels of estrogen and progesterone prepare the breasts for lactation. The areolae of the breasts usually become deeply pigmented, and sebaceous glands in the nipples (tubercles of Montgomery) become prominent. The tubercles secrete a substance that lubricates the nipples. In the last few months of pregnancy, a thin yellow fluid called colostrum may be expressed from the breasts. This “premilk” is high in protein, fat-soluble vitamins, and minerals, but it is low in calories, fat, and sugar. Colostrum contains the mother’s antibodies to diseases and is secreted for the first 2 to 3 days after birth in the breastfeeding woman. 146 Respiratory system The pregnant woman breathes more deeply, but her respiratory rate increases only slightly, if at all. These changes increase oxygen and carbon dioxide exchange because she moves more air in and out with each breath. Oxygen consumption increases by 15% during pregnancy. The expanding uterus exerts upward pressure on her diaphragm, causing it to rise about 4 cm (1.6 inch). To compensate, her rib cage flares, increasing the circumference of the chest about 6 cm (2.4 inches). Dyspnea may occur until the fetus descends into the pelvis (lightening), relieving upward pressure on the diaphragm. Increased estrogen levels during pregnancy cause edema or swelling of the mucous membranes of the nose, pharynx, mouth, and trachea. The woman may have nasal stuffiness, epistaxis (nosebleeds), and changes in her voice. A similar process occurs in the ears, causing a sense of fullness or earaches. Cardiovascular system The growing uterus displaces the heart upward and to the left. The blood volume gradually increases (hypervolemia) to about 45% greater than that of the prepregnant state by 32 to 34 weeks gestation, at which time it levels off or declines slightly. This increase provides added blood for the following purposes: • Exchange of nutrients, oxygen, and waste products within the placenta • Needs of expanded maternal tissue • Reserve for blood loss at birth Cardiac output increases because more blood is pumped from the heart with each contraction, the pulse rate increases by 10 to 15 beats/min, and the basal metabolic rate may increase 20% during pregnancy. Blood pressure does not increase with the higher blood volume because resistance to blood flow through the vessels decreases. A blood pressure of 140/90 mm Hg or a significant elevation above the woman’s baseline measurement calls for attention. Supine hypotension syndrome, also called aortocaval compression or vena cava syndrome, may occur if the woman lies on her back (Fig. 4.5). The supine position allows the heavy uterus to compress her inferior vena cava, reducing the amount of blood returned to her heart. Circulation to the placenta may also be reduced by increased pressure on the woman’s aorta, resulting in fetal hypoxia. Symptoms of supine hypotension syndrome include faintness, lightheadedness, dizziness, and agitation. Displacing the uterus to one side by turning the patient (preferably to the left) is all that is needed to relieve the pressure. If the woman must remain flat for any reason, a small towel roll placed under one hip will also help to prevent supine hypotension syndrome. FIG. 4.5 Supine hypotension syndrome. When a pregnant woman lies on her back (supine), the weight of the uterus with its fetal contents presses on the vena cava and the abdominal aorta. Placing a wedge pillow under the woman’s right hip helps to relieve compression of these vessels. (From Matteson PS: Women’s health during the childbearing years: a community-based approach, St. Louis, 2001, Mosby.) 147 Orthostatic hypotension may occur whenever a woman rises from a recumbent position, resulting in faintness or lightheadedness. Cardiac output decreases because venous return from the lower body suddenly drops. Palpitations (sudden increase in heart rate) may occur from increases in thoracic pressure, particularly if the woman moves suddenly. Although both plasma (fluid) and red blood cells (erythrocytes) increase during pregnancy, they do not increase by the same amount. The fluid part of the blood increases more than the erythrocyte component. This leads to a dilutional anemia or pseudoanemia (false anemia). As a result, the normal prepregnant hematocrit level of 36% to 48% may fall to 33% to 46%. Although this is not true anemia, the hematocrit count is reevaluated to determine patient status and needs. The white blood cell (leukocyte) count also increases about 8% (mostly neutrophils) and returns to prepregnant levels by the sixth day postpartum (Table 4.3). Table 4.3 Normal Blood Values in Nonpregnant and Pregnant Women Value Hemoglobin (g/dL) Hematocrit (%) Red blood cells (million/mm3) White blood cells (increase during labor and postpartum up to 25,000/mm3) Fibrinogen (mg/dL) Nonpregnant 12–16 36–48 3.8–5.1 5000–10,000/mm3 200–400 Pregnant 11–12 (10.5 in second trimester) 33–46 (33 in second trimester) 4.5–6.5 5000–15,000/mm3 300–600 Data from Blackburn S: Maternal, fetal and neonatal physiology: a clinical perspective, ed 4, Philadelphia, 2013, Saunders. There are increased levels of clotting factors VII, VIII, and X and plasma fibrinogen during the second and third trimesters of pregnancy. This hypercoagulability state helps prevent excessive bleeding after delivery when the placenta separates from the uterine wall. However, these changes increase the possibility of thrombophlebitis during pregnancy and are the reason that the pregnant patient requires careful assessment for this risk and specific teaching to prevent venous stasis that can lead to thrombophlebitis. The current increased interest in physical fitness has resulted in many pregnant women continuing to exercise during pregnancy. The effects of exercise on the cardiovascular system that already has an increased blood volume, increased cardiac output, and increased coagulability during pregnancy must be reviewed before an exercise plan is implemented. Venous pressure may increase in the femoral veins as the size and weight of the uterus increase, resulting in varicose veins in the legs of some women. Gastrointestinal system The growing uterus displaces the stomach and intestines toward the back and sides of the abdomen (Fig. 4.6). Increased salivary secretion (ptyalism) sometimes affects taste and smell. The mouth tissues may become tender and bleed more easily because of increased blood vessel development caused by high estrogen levels. Contrary to popular belief, teeth are not affected by pregnancy. 148 FIG. 4.6 Compression of abdominal contents as uterus enlarges. The nonpregnant state (A) shows the relationship of the uterus to the abdominal contents. As the uterus enlarges at 20 weeks gestation (B) and 30 weeks gestation (C), the abdominal contents are displaced and compressed. (From Moore KL, Persaud TVN, Torchia MG: The developing human: clinically oriented embryology, ed 10, Philadelphia, 2016, Saunders.) The demands of the growing fetus increase the woman’s appetite and thirst. The acidity of gastric secretions is decreased; emptying of the stomach and motility (movement) of the intestines are slower. Women often feel bloated and may experience constipation and hemorrhoids. Pyrosis (heartburn) is caused by the relaxation of the cardiac sphincter of the stomach, which permits reflux (backward flow) of the acid secretions into the lower esophagus. Glucose metabolism is altered because of increased insulin resistance during pregnancy. This allows more glucose use by the fetus but also places the woman at risk for the development of gestational diabetes mellitus. Progesterone and estrogen relax the muscle tone of the gallbladder, resulting in the retention of bile salts, and this can lead to pruritus (itching of the skin) during pregnancy. Urinary system The urinary system excretes waste products for both the mother and the fetus during pregnancy. The glomerular filtration rate of the kidneys increases. The renal tubules increase the reabsorption of substances that the body needs to conserve, but the tubules may not be able to keep up with the high load of some substances filtered by the glomeruli (e.g., glucose). Therefore glycosuria and proteinuria are more common during pregnancy. Water is retained because it is needed for increased blood volume and for dissolving nutrients that are provided for the fetus. The relaxing effects of progesterone cause the renal pelvis and ureters to lose tone, resulting in decreased peristalsis to the bladder. The diameter of the ureters and the bladder capacity increase because of the relaxing effects of progesterone, causing urine stasis. The combination of urine stasis and nutrient-rich urine makes the pregnant woman more susceptible to urinary tract infection. Consuming at least eight glasses of water each day reduces the risk for urinary tract infection. Although the bladder can hold up to 1500 mL of urine, the pressure of the enlarging uterus causes increasing frequency of urination, especially in the first and third trimesters. Changes in the renal system may take 6 to 12 weeks after delivery to return to the prepregnant state. Fluid and Electrolyte Balance The increased glomerular filtration rate in the kidneys increases sodium filtration by 50%, but the increase in the tubular resorption rate results in 99% reabsorption of the sodium. Sodium retention is influenced by many factors including elevated levels of the hormones of pregnancy. Although the fetus uses much of the sodium, the remainder is in the maternal circulation and can cause a maternal accumulation of water (edema). This fluid retention may cause a problem if the woman in labor is given intravenous fluids containing oxytocin (Pitocin), which has an antidiuretic effect and can result in water intoxication. Agitation and delirium—possible signs of water intoxication— 149 should be recorded and reported, and an accurate intake and output record should be kept during labor and the immediate postpartum phase. In pregnancy, blood is slightly more alkaline than in the nonpregnant state, and this mild alkalemia is enhanced by the hyperventilation that often occurs during pregnancy. This status does not affect a normal pregnancy. Integumentary and skeletal systems The high levels of hormones produced during pregnancy cause a variety of temporary changes in the integument (skin) of the pregnant woman. In addition to the pigmentary changes discussed in the earlier section Presumptive Signs of Pregnancy, the sweat and sebaceous glands of the skin become more active to dissipate heat from the woman and fetus. Small red elevations of skin with lines radiating from the center, called spider nevi, may occur. The palms of the hands may become deeper red. Most skin changes are reversed shortly after giving birth. The woman’s posture changes as her child grows within the uterus. The anterior part of her body becomes heavier with the expanding uterus, and the lordotic curve in her lumbar spine becomes more pronounced. The woman often experiences low backaches, and, in the last few months of pregnancy, rounding of the shoulders may occur along with aching in the cervical spine and upper extremities. The pelvic joints relax with hormonal changes during late pregnancy and entry of the fetal presenting part into the pelvic brim in the last trimester. A woman often has a “waddling” gait in the last few weeks of pregnancy because of a slight separation of the symphysis pubis. Safety Alert! A change in the center of gravity and joint instability because of the softening of the ligaments predispose the pregnant woman to problems with balance. Interventions concerning safety should be part of prenatal education. 150 Nutrition for pregnancy and lactation Good nutrition is vital to good health and essential for normal growth and development. It is also essential to establish and maintain a healthy pregnancy and give birth to a healthy infant. Good nutritional habits begun before conception and continued during pregnancy promote adaptation to the maternal and fetal needs. In a joint effort, the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services created MyPlate, which offers dietary guidelines for Americans (Fig. 4.7). An example of how a food pyramid can be modified to fit Latin American dietary preferences is shown in Fig. 4.8. 151 FIG. 4.7 (A) MyPlate is based on the 2010 dietary guidelines for Americans to encourage healthy eating for all people. The colors on the plate illustrate the five food groups as a place setting for a meal, showing approximate portion size recommended for proteins, vegetables, fruits, grains, and dairy. Consumers can access the website www.Choosemyplate.gov to find printable references, sample menus, and 152 recommended foods for each food group. (B) The U.S. Department of Agriculture site provides specific recommendations for pregnant women. (Courtesy U.S. Department of Agriculture.) 153 FIG. 4.8 The traditional healthy Latin American diet pyramid. This diet pyramid is a modification of the North American diet and has daily physical activity as its base. It contains foods common to the Latin American diet. (© Oldways Preservation and Exchange Trust, 2009.) Nutrition Considerations 154 Maternal Diet and Fetal Health There is a high correlation between maternal diet and fetal health. To ensure that deficiencies do not occur during the critical first weeks of pregnancy, the nurse explains to women of childbearing age the value of eating well-balanced meals so they may start pregnancy in a good nutritional state. A healthy, balanced, nutrient-dense diet combined with adequate physical activity is the core of the revised dietary guidelines. A personalized portion-sized diet plan that includes individualized advice on activity level is available online at www.MyPyramid.gov. Additional recommendations for specific populations can be found at www.healthierus.gov/dietaryguidelines. Women who follow this guide before pregnancy will be well nourished at the time of conception. Before and during pregnancy, women should read food labels carefully to promote the intake of calories that are nutrient dense rather than empty. During pregnancy and lactation, an adequate dietary intake of docosahexaenoic acid–omega 3 fatty acid (DHA) is essential for optimal brain development of the fetus and infant. Dietary sources are preferred (Gould et al, 2017). Fish oil supplements in pregnancy may be associated with a decrease in asthma and wheezing in the offspring. Research is ongoing (Ramsden, 2016). The World Health Organization recommends that a full-term infant receive 20 mg of DHA per kilogram per day. Maternal dietary sources of DHA include fish such as mackerel, Atlantic and sockeye salmon, halibut, tuna, and flounder; egg yolk; red meat; poultry; canola oil; and soybean oil. Two to three servings per week are recommended. Frying these foods detracts from DHA content. See Table 15.6 for culturally diverse food patterns. Nursing Care Plan 4.1 lists some common nursing diagnoses and suggested interventions related to nutrition during pregnancy and lactation. Nursing Care Plan 4.1 Nutrition During Pregnancy and Lactation Patient data Mrs. Switzer is seen in the clinic. She is 35 years old, in the first trimester of her first pregnancy, and appears interested in learning how to “start a healthy diet” in order to have a healthy pregnancy outcome. Selected Nursing Diagnosis: Need for education concerning the importance of nutrition in pregnancy and lactation Goals Patient will verbalize the need for good nutrition during pregnancy and lactation. Nursing Interventions Determine age, parity, present weight, prepregnant nutritional status, food preferences and dislikes, food intolerances, and general health of pregnant patient. Determine socioeconomic and cultural factors that may influence food choices. Make recommendations to fit specific needs. Consult with a dietitian if patient’s nutritional needs are complex. Review specific nutritional needs and food sources for optimal outcome of pregnancy and successful lactation. Provide written information in patient’s primary language regarding nutrition and food preparation. Modify information to incorporate cultural practices or food dislikes or intolerances. Encourage questions and provide appropriate answers. Patient will implement Teach patient the purpose of and how to good nutrition during maintain a 24-hour food diary. Teach pregnancy and patient to eat normally and to write down lactation, as evidenced everything she eats and drinks, including Rationales Many factors influence nutritional status of patient during pregnancy and lactation; nutrition teaching must be individualized to best meet her pregnancy nutritional needs. Socioeconomic and cultural factors affect patient’s food choices. These factors must be considered to increase the chance that patient will adhere to dietary recommendations. The assessment may identify the need for referral to programs such as the Women, Infants, and Children (WIC) nutrition program. If patient understands specific nutritional needs of pregnancy and food sources, she is more likely to choose foods that meet these needs. Written information reinforces verbal teaching and helps patient to recall forgotten information. Recommendations must fit within patient’s individualized needs to increase the chance that she will adhere to them. Encouraging patient’s questions allows nurse to identify and correct areas of inadequate knowledge or misunderstanding. A 24-hour food diary helps nurse to evaluate patient’s usual diet and her likes and dislikes as well as how to improve her diet. It may help identify the need for a dietitian referral. 155 by a 24-hour diary. approximate amounts, for 1 day. Review the 24-hour intake from diary and make appropriate recommendations for improvement. Refer to a dietitian if nutritional assessment shows complex needs. Teach patient about MyPlate food guide and how to read food labels. Patient will demonstrate a gradual weight gain appropriate for her pregnancy (25 to 35 lb for most women). Maintain a chart to show patient’s actual weight at each visit. Analysis of usual meals and snacks enables nurse to identify adequate and inadequate intake of specific nutrients. The 24-hour diary allows nurse to reinforce areas of adequate intake and concentrate on areas of deficient nutrients. Choices on MyPlate food guide provide essential nutrients on a daily basis. Reading labels helps patient to select more nutritious items from those that are available. Weight chart identifies both the amount and the pattern of weight gain to identify inadequate or excessive gain. Review progress of weight with patient at Reviewing patient’s weight identifies whether patient’s weight gain each visit and compare it with is normal and whether additional teaching or exploration of needs is recommended amount of gain for that point required. in pregnancy. Critical thinking questions 1. Mrs. Switzer says she is anxious to complete the clinic appointment because she wants to “light up a cigarette.” What is your major concern about her smoking? What interventions would be appropriate? 2. Mrs. Switzer states that her dietary pattern is heavily influenced by her perceived “food cravings,” which have occurred increasingly in the past month. What would be your approach to this problem? Recommended dietary allowances and recommended dietary intakes In the United States, the Food and Nutrition Board of the Institute of Medicine (IOM), the National Academy of Science in cooperation with the USDA, and the U.S. Department of Health and Human Services developed recommended dietary allowances (RDAs) of nutrient intake required to maintain optimal health. In the past, RDAs reflected the fact that nutrients were primarily supplied by foods, in particular, nonfortified ones. Research by the Food and Nutrition Board showed an increasing use of dietary supplements and fortified foods, resulting in the need to describe upper limits of intake levels to prevent toxicity. Adverse responses (toxicity) can occur if the combination of intake in the form of supplements and food, whether fortified or not, exceeds the present upper limits of safety. When scientific evidence is insufficient to determine RDA, an adequate intake is likely provided by an adequate diet. Consuming dietary supplements of trace elements can result in toxicity if upper limits of intake are consistently exceeded. The Committee of the USDA Human Nutrition and Research Center published recommended dietary intakes (RDIs) focusing on specific nutrients (http://fnic.nal.usda.gov). Research is ongoing. Future nutrient recommendations will be expressed as dietary reference intakes (DRIs). DRI is an umbrella term that includes the RDA and tolerable upper levels of intake. The RDA will be retained for any nutrient for which revision to the new DRI has not been made, and both RDAs and RDIs will be used until research is completed. Current RDAs and RDIs of nutrients for various age groups, including those for pregnant and lactating women, can be found on the Evolve website or in a nutrition textbook. Safety Alert! Avoid exceeding recommended dosages of vitamins and minerals because a balance is needed for health. For example, excess intake of vitamin C can inhibit the absorption of vitamin B12. Weight gain 156 In the past a woman’s weight gain was restricted during pregnancy. It was thought that minimal weight gain would keep the fetus small and therefore easier to deliver. Evidence shows that low maternal weight gain is associated with complications such as preterm la