NCM 107 (MIDTERM).pdf

# MODULE 3: The Growing Fetus ## TOPIC OUTLINE - STEM CELLS - ZYGOTE GROWTH - PRIMARY GERM LAYERS - ORGANOGENESIS - CARDIOVASCULAR SYSTEM - RESPIRATORY SYSTEM - NERVOUS SYSTEM - ENDOCRINE SYSTEM - DIGESTIVE SYSTEM - MUSCULOSKELETAL SYSTEM - REPRODUCTIVE SYSTEM - URINARY SYSTEM - INTEGUMANTARY SYSTEM...

# MODULE 3: The Growing Fetus ## TOPIC OUTLINE - STEM CELLS - ZYGOTE GROWTH - PRIMARY GERM LAYERS - ORGANOGENESIS - CARDIOVASCULAR SYSTEM - RESPIRATORY SYSTEM - NERVOUS SYSTEM - ENDOCRINE SYSTEM - DIGESTIVE SYSTEM - MUSCULOSKELETAL SYSTEM - REPRODUCTIVE SYSTEM - URINARY SYSTEM - INTEGUMANTARY SYSTEM - IMMUNE SYSTEM - SUMMARY ## STEM CELLS - During the first 4 days of life, zygote cells are termed totipotent stem cells. - In another four days, it becomes an embryo. Cells begin to show differentiation and lose their ability to become any body cell. - Pluripotent stem cell - slated to become specific body cells (eg nerve, brain or skin cells). - In yet another few days, the cells grow so specific that they are termed multipotent or are so specific that they have set a sure course toward the body organ they will create. ## ZYGOTE GROWTH - From the beginning of fetal growth, development proceeds in a cephalocaudal direction. - This pattern of development continues after birth as shown by the way infants are able to lift up their heads approximately 1 year before they are able to walk. - As a fetus grows, body organ systems develop from specific tissue layers called germ layers. ## PRIMARY GERM LAYERS - Blastocyst - Inner structure: - Amniotic cavity -> ectoderm - Mesoderm - Yolk sac -> entoderm - The yolk sac provides a source of red blood cells until embryo’s hematopoietic system is mature enough to perform this function. ## PRIMARY GERM LAYERS | Layer | Function | |---|---| | **ECTODERM** | - Central nervous system (brain and spinal cord) - Peripheral nervous system - Skin, hair, and nails - Sebaceous glands - Sense organs of the anus, mouth, and nose - Mucous membranes of the anus, mouth, and nose - Tooth enamel - Mammary glands | | **MESODERM** | - Supporting structures of the body (connective tissue, bones, cartilage, tendons) - Muscle, ligaments, and nails - Dentin of teeth - Upper portion of the urinary system (kidneys and ureters) - Reproductive system - Heart - Circulatory system - Blood cells - Lymph vessels | | **ENTODERM** | - Lining of pericardial, pleura, and peritoneal cavities - Lining of the gastrointestinal tract, respiratory tract, tonsils, parathyroid, thymus glands - Lower urinary system (bladder and urethra) | ## ORGANOGENESIS - Organogenesis - organ formation - All organ systems are complete, at least in a rudimentary form, at 8 weeks’ gestation (the end of the embryonic period). - During this time, the structure is most vulnerable to invasion by teratogens. - Teratogens - any factor that adversely affects the fertilized ovum, embryo, or fetus, such as cigarette smoking ## CARDIOVASCULAR SYSTEM - One of the first systems to become functional in intrauterine life. - 16th DOL – single heart tube is formed. - 24th DOL – first heartbeat. - 6th-7th week – septum that divides the heart develops. - 7th week – heart valves begin to develop. - 10th-12th week – heartbeat may be heard by a Doppler instrument. - 28th week – SNS matures, stabilizing HR to 110-160 bpm ## FETAL CIRCULATION - The blood oxygen saturation level of the fetus is about 80% of a newborn's saturation level. - The rapid fetal heart rate during pregnancy (120-160 beats per minute) is necessary to supply oxygen to cells, because the red blood cells are never fully saturated. ## FETAL HEMOGLOBIN | Type | Description | |---|---| | **FETAL HEMOGLOBIN** | Two alpha and two gamma chains More concentrated Has greater affinity for oxygen | | **ADULT HEMOGLOBIN** | Two alpha and two beta chains | ## RESPIRATORY SYSTEM - 3rd week of intrauterine life - respiratory and digestive tracts exist as a single tube. - 4th week - septum begins to divide esophagus from the trachea; lung buds appear on the trachea. - 7th week - diaphragm does not completely divide the thoracic cavity from the abdomen. - If the diaphragm fails to close completely, the stomach, spleen, liver, or intestines may be pulled up into the thoracic cavity = diaphragmatic hernia. - 24th-28th week - alveoli and capillaries begin to form. - 3 mos AOG - spontaneous respiratory practice movements begin. - Surfactant - phospholipid substance. - Formed and excreted by alveolar cells at about the 24th week of pregnancy. - Decreases alveolar surface tension on expiration, preventing alveolar collapse and improving infant’s ability to maintain respirations in the outside environment. - Surfactant - Two components: - Lecithin - Sphingomyelin - Early in the formation of surfactant, sphingomyelin is the chief component - 35 wks AOG - surge of production of lecithin; L/S ratio becomes 2:1. ## NERVOUS SYSTEM - 3rd week AOG - neural plate (thickened portion of ectoderm) - Top portion - neural tube -> CNS - Neural crest -> PN - All parts of the brain (cerebrum, cerebellum, pons and medulla oblongata) form in utero, although none completely mature at birth - Brain growth continues at high levels until 5-6 years old - 24 wks AOG ear is capable of responding to sound; the eyes exhibit pupillary reaction. - Brain waves can be detected by EEG at 8 wks AOG. ## ENDOCRINE SYSTEM - As soon as endocrine organs mature in intrauterine life, function begins. - The fetal adrenal glands supply a precursor necessary for estrogen synthesis by the placenta. - The fetal pancreas produces insulin needed by the fetus. - The thyroid and parathyroid glands play vital roles in fetal metabolic function and calcium balance. ## DIGESTIVE SYSTEM - 4th WOL - digestive tract separates from respiratory tract - Atresia - blockage - Stenosis - narrowing - 6th WOL - intestine becomes too large to be contained by the abdomen - A portion of the intestine, guided by the vitelline membrane (a part of the yolk sac), is pushed into the base of the umbilical cord, where it remains until about the 10th week. - 10th WOL - the intestine goes back to the abdominal cavity - As the intestine returns to the abdominal cavity at this point, it must rotate 180 degrees. - Failure to do so can result in inadequate mesentery attachments, possibly leading to volvulus of the intestine in the newborn. - Omphalocele - If any intestine remains outside the abdomen in the base of the cord. - Gastroschisis – original midline fusion that occurred at the early cell stage is incomplete. ## GASTRASCHISIS - Meckel’s diverticulum - If the vitelline duct does not atrophy after return of the intestines. - Meconium a collection of cellular wastes, bile, fats, mucoproteins, mucopolysaccharides, and portions of the vernix caseosa accumulates in the intestines as early as the 16th week. - Vernix caseosa - lubricating substance that forms on fetus’ skin. - Meconium is sticky in consistency and appears black or dark green (obtaining its color from bile pigment). ## MECONIUM OF A 12-HOUR OLD NEWBORN - The gastrointestinal tract is sterile before birth. - Because vitamin K is synthesized by the action of bacteria in the intestines, vitamin K levels are low in the newborn. - Sucking and swallowing reflexes are not mature until the fetus is at about 32 weeks’ gestation or weighs 1500 g. - The ability of the gastrointestinal tract to secrete enzymes essential to carbohydrate and protein digestion is mature at 36 weeks. - The liver is active throughout gestation, but still immature at birth. - Functions as filter between the incoming blood and the fetal circulation, and as a deposit site for fetal stores such as iron and glycogen. - Immaturity of the liver can lead to hypoglycemia and/or hyperbilirubinemia at birth. - The liver does not prevent recreational drugs or alcohol ingested by the mother from entering the fetal circulation. ## MUSCULOSKELETAL SYSTEM - During the first 2 weeks of fetal life, cartilage prototypes provide position and support. - Ossification of this cartilage into bone begins at about the 12th week. - Ossification continues all through fetal life and actually until adulthood. - Carpals, tarsals, and sternal bones generally do not ossify until birth is imminent. ## INTEGUMENTARY SYSTEM - The skin of a fetus appears thin and almost translucent until subcutaneous fat begins to be deposited at about 36 weeks. - Lanugo - soft downy hairs that serve as insulation to preserve warmth - Vernix caseosa - a cream cheese-like substance important for lubrication and for keeping the skin from macerating in utero. ## REPRODUCTIVE SYSTEM - 6th WOL - gonads form. - If testes form - testosterone is secreted, influencing the genital duct to form other male organs. - In the absence of testosterone, female organs will form. - The testes first form in the abdominal cavity and do not descend into the scrotal sac until the 34th to 38th week. - Because of this, many male preterm infants are born with undescended testes. ## URINARY SYSTEM - 4th WOL - rudimentary kidneys are present. - 12th WOL - urine is formed. - 16th WOL - urine is excreted into the amniotic fluid. - At term, fetal urine is 500mL/day. - Early in the embryonic stage of urinary system development, the bladder extends as high as the umbilical region. - Patent urachus - an open lumen between the urinary bladder and the umbilicus fails to close. ## IMMUNE SYSTEM - Immunoglobulin G (IgG) maternal antibodies cross the placenta into the fetus as early as the 20th week and certainly by the 24th week of intrauterine life to give a fetus temporary passive immunity against diseases for which the mother has antibodies. - Poliomyelitis - Rubella (German measles) - Rubeola (regular measles) - Diphtheria - Tetanus, - Infectious parotitis (mumps) - Hepatitis B - Pertussis (whooping cough) - Little or no immunity to the herpes virus (the virus of chickenpox, cold sores, and genital herpes) is transferred to the fetus, so the average newborn is potentially susceptible to these diseases. - The recommended immunization for teenagers against the virus should reduce the incidence of this in newborns. - Infants born before antibody transfer has taken place have no natural immunity and need more than the usual protection against infectious disease in the newborn period. - The level of these acquired passive IgG immunoglobulins peaks at birth and then decreases over the next 8 months as the infant builds up his or her own stores of IgG, as well as IgA and IgM. - Because the passive immunity received by the newborn has already declined substantially by about 2 months, immunization against diphtheria, tetanus, pertussis, poliomyelitis, rotovirus, Haemophilus influenzae, and pneumococcus is typically started at this time. - Passive antibodies to measles have been demonstrated to last for longer than 1 year. - Consequently, the immunization for measles is not given until an extrauterine age of 12 months. - A fetus is capable of active antibody production late in pregnancy, but normally not necessary because antibodies are manufactured only after stimulation by an invading antigen, and antigens rarely invade the intrauterine space. - However, infants whose mothers have had an infection such as rubella during pregnancy typically have active IgM antibodies to rubella in their blood serum at birth. - Because IgA and IgM antibodies cannot cross the placenta, their presence in a newborn is proof that the fetus has been exposed to a disease. ## SUMMARY - The union of a single sperm and egg (fertilization) signals the beginning of pregnancy. - The fertilized ovum (zygote) travels by way of a fallopian tube to the uterus, where implantation takes place in about 8 days. - From implantation to 5 to 8 weeks, the growing structure is called an embryo. The period after 8 weeks until birth is the fetal period. - Growth of the umbilical cord, amniotic fluid, and amniotic membranes proceeds in concert with fetal growth. - The placenta produces several important hormones: estrogen, progesterone, human placental lactogen, and human chorionic gonadotropin. # MODULE 3: Fetal Growth and Development ## TOPIC OUTLINE - MILESTONES OF FETAL GROWTH AND DEVELOPMENT - MILESTONES OFFETAL GROWTH AND DEVELOPMENT - ASSESSING FETAL GROWTH AND DEVELOPMENT - RHYTHM STRIP TESTING - NON-STRESS TEST - CONTRACTION STRESS TEST - ULTRASONOGRAPHY - AMNIOCENTESIS - SUMMARY ## MILESTONES OF FETAL GROWTH AND DEVELOPMENT - **OVULATION AGE** - Life of the fetus is typically measured from the time of ovulation or fertilization. - **GESTATIONAL AGE** - Length of pregnancy is more commonly measured from the first day of the last menstrual period (LMP). - Ovulation and fertilization take place about 2 weeks after the last menstrual period. - Ovulation age of the fetus is always 2 weeks less the length of the pregnancy or the gestational age. - Both ovulation and gestational age are typically reported in lunar months (4-week periods) or in trimesters (3-month periods) rather than in weeks. - In lunar months, a pregnancy is 10 months (40 weeks, or 280 days) long; a fetus grows in utero 9.5 lunar months or three full trimesters (38 weeks, or 266 days). ## MILESTONES OF FETAL GROWTH AND DEVELOPMENT - **End of 4th Gestational Week** - At the end of the fourth week of gestation, the human embryo is a group of rapidly growing cells but does not yet resemble a human being. - Length: 0.75 1cm - Weight: 400 mg - The spinal cord is formed and fused at the midpoint. - Lateral wings that will form the body are folded forward to fuse at the midline. - The head folds forward and becomes prominent, representing about onethird of the entire structure. - The back is bent so that the head almost touches the tip of the tail. - The rudimentary heart appears as a prominent bulge on the anterior surface. - Arms and legs are budlike structures. - Rudimentary eyes, ears, and nose are discernible. - **End of 8th Gestational Week** - Length: 2.5 cm (1 in) - Weight: 20 g - Organogenesis is complete. - The heart, with a septum and valves, is beating rhythmically. - Facial features are definitely discernible. - Arms and legs have developed. - External genitalia are forming, but sex is not yet distinguishable by simple observation. - The primitive tail is regressing. - The abdomen bulges forward because the fetal intestine is growing so rapidly. - An ultrasound shows a gestational sac, diagnostic of pregnancy - **End of 12th Gestational Week** - Length: 78 cm - Weight: 45 g - Nail beds are forming on fingers and toes. - Spontaneous movements are possible, although they are usually too faint to be felt by the mother. - Some reflexes, such as the Babinski reflex, are present. - Bone ossification centers begin to form. - Tooth buds are present. - Sex is distinguishable by outward appearance. - Urine secretion begins but may not yet be evident in amniotic fluid. - The heartbeat is audible through Doppler technology. - **End of 16th Gestational Week** - Length: 10-17 cm - Weight: 55-120 g - Fetal heart sounds are audible by an ordinary stethoscope. - Lanugo is well formed. - Liver and pancreas are functioning. - Fetus actively swallows amniotic fluid, demonstrating an intact but uncoordinated swallowing reflex; urine is present in amniotic fluid. - Sex can be determined by ultrasound - **End of 20th Gestational Week** - Length: 25 cm - Weight: 223 g - Spontaneous fetal movements can be sensed by the mother. - Antibody production is possible. - The hair forms on the head, extending to include eyebrows. - Meconium is present in the upper intestine. - Brown fat, a special fat that will aid in temperature regulation at birth, begins to be formed behind the kidneys, sternum, and posterior neck. - Vernix caseosa begins to form and cover the skin. ## ASSESSING FETAL GROWTH AND DEVELOPMENT - **Determination of Estimated Birth Date** - Estimated date of confinement (EDC), or estimated date of delivery (EDD) - If fertilization occurred early in a menstrual cycle, the pregnancy will probably end "early"; if ovulation and fertilization occurred later in the cycle, the pregnancy will end "late." - A pregnancy ending 2 weeks before or 2 weeks after the calculated EDB is considered well within the normal limit (38-42 weeks). - Gestational age wheels - Birth date calculators - *Nageles rule* - **Nageles Rule** - To calculate the date of birth by this rule, count backward 3 calendar months from the first day of a woman's last menstrual period and add 7 days. - For example, if the last menstrual period began May 15, you would count back 3 months (April 15, March 15, February 15) and add 7 days, to arrive at a date of birth of February 22. -**Conditions That Interfere With Fetal Growth and Development** - Metabolic or chromosomal disorder that interferes with normal growth. ## ASSESSING FETAL GROWTH AND DEVELOPMENT - Fetal death can be revealed by a lack of heartbeat and respiratory movement. - After birth, an ultrasound may be used to detect a retained placenta or poor uterine involution in the new mother. - **Intermittent sound waves of high frequency (above the audible range) are projected toward the uterus by a transducer placed on the abdomen or in the vagina.** - The sound frequencies that bounce back can be displayed on an oscilloscope screen as a visual image. - The frequencies returning from tissues of various thicknesses and properties present distinct appearances. - A permanent record, such as a video or photograph, can be made of the scan. - Before an ultrasound examination, be sure that a woman has received a good explanation of what will happen and reassurance that the process does not involve x-rays. - It is helpful if the woman has a full bladder at the time of the procedure. - *Rationale: The sound waves will reflect best and the uterus will be held stable.* - To ensure this, have her drink a full glass of water every 15 minutes beginning 90 minutes before the procedure and not void until after the procedure. - Help the woman up to an examining table and drape her for modesty, but with her abdomen exposed. - Place a towel under her right buttock to tip her body slightly. - *Rationale: In this position, the uterus will roll away from the vena cava and prevent supine hypotension syndrome.* - A gel is then applied to her abdomen to improve the contact of the transducer. - *!!! Be certain that the gel is at room temperature or even slightly warmer, or it can cause uncomfortable uterine cramping.* - The transducer is then applied to her abdomen and moved both horizontally and vertically until the uterus and its contents are fully scanned. ## AMNIOCENTESIS - From the Greek word amnion for "sac" and kentesis for "puncture". - The aspiration of amniotic fluid from the pregnant uterus for examination. - Typically scheduled between the 14th and 16th weeks of pregnancy to allow for a generous amount of amniotic fluid to be present. - The technique can be used again near term to test for fetal maturity. - Technically easy procedure, but can be frightening to a woman. - Fetal risk: less than 0.5% - Fetal complications: - hemorrhage from penetration of the placenta - infection of the amniotic fluid - puncture of the fetus - irritation of the uterus premature labor - In preparation for amniocentesis, ask the woman to void. - *Rationale: reduce the size of the bladder and prevent an inadvertent puncture. Place her in a supine position on an examining table and drape her appropriately, exposing only her abdomen. Place a folded towel under her right buttock to tip her body slightly to the left.* - Attach fetal heart rate and uterine contraction monitors. - Take her blood pressure and measure the fetal heart rate for baseline levels. - An ultrasound is then done to determine the position of the fetus and the location of a pocket of amniotic fluid and the placenta. - The abdomen is then washed with an antiseptic solution, and a local anesthetic is injected. - Caution the woman that she may feel a sensation of pressure as the needle used for aspiration, a 3- or 4-in, 20- to 22-gauge spinal needle, is introduced. - *!!! Do not suggest that she take a deep breath and hold it as a distraction against discomfort.* - *Rationale: This lowers the diaphragm against the uterus and shifts intrauterine contents.* - The needle is inserted until it reaches the amniotic cavity and a pool of amniotic fluid, carefully avoiding the fetus and placenta. - Syringe is attached, and about 15 mL of amniotic fluid is withdrawn. - The needle is then removed, and the woman rests quietly for about 30 minutes. - Observe fetal heart rate and uterine contractions during and after the procedure. ## SUMMARY - Various methods to assess fetal growth and development include fundal height, fetal movement, fetal heart tones, ultrasonography, magnetic resonance imaging, maternal serum alpha-fetoprotein, amniocentesis, percutaneous umbilical blood sampling, amnioscopy, and fetoscopy. - A biophysical profile is a combination of fetal assessments that predicts fetal well-being better than measuring single parameters. ## RHYTHM STRIP TESTING - Help a woman into a semi-Fowler's position (either in a comfortable lounge chair or on an examining table or bed with an elevated backrest). - *Rationale: prevent her uterus from compressing the vena cava and causing supine hypotension syndrome during the test.* - Attach an external fetal heart rate monitor abdominally. - Record the fetal heart rate for 20 minutes. - Rhythm strip testing requires a woman to remain in a fairly fixed position for 20 minutes. - Keep her well informed of the purpose of the test, how it is interpreted, and the meaning of results after the test. ## NON-STRESS TEST - Measures the response of the fetal heart rate to fetal movement. - When the fetus moves, the fetal heart rate should increase about 15 beats per minute and remain elevated for 15 seconds. - It should decrease to its average rate again as the fetus quiets. - If no increase in beats per minute is noticeable on fetal movement, poor oxygen perfusion of the fetus is suggested. - A nonstress test usually is done for 10 to 20 minutes. - **Reactive test** - if two accelerations of fetal heart rate (by 15 beats or more) lasting for 15 seconds occur after movement within the chosen time period. - **Non-reactive test** - if no accelerations occur with the fetal movements. - The results also can be interpreted as nonreactive if no fetal movement occurs or if there is low short-term fetal heart rate variability (less than 6 beats per minute) throughout the testing period. - If a 20-minute period passes without any fetal movement, it may mean only that the fetus is sleeping. - Other reasons: maternal smoking, drug use, or hypoglycemia. - If you give the woman an oral carbohydrate snack, such as orange juice, it can cause her blood glucose level to increase enough to cause fetal movement. - The fetus also may be stimulated by a loud sound to cause movement. - Position a woman and attach both a fetal heart rate and a uterine contraction monitor. - Instruct a woman to push a button attached to the monitor (similar to a call bell) whenever she feels the fetus move. This will create a dark mark on the paper tracing at these times. ## CONTRACTION STRESS TEST - With contraction stress testing, the fetal heart rate is analyzed in conjunction with contractions. - *Source of oxytocin for contraction stress testing currently is achieved by nipple stimulation. Gentle stimulation of the nipples releases oxytocin in the same way as happens with breastfeeding.* - With external uterine contraction and fetal heart rate monitors in place, the baseline fetal heart rate is obtained. - Next, the woman rolls a nipple between her finger and thumb until uterine contractions begin, which are recorded by a uterine monitor. - Three contractions with a duration of 40 seconds or longer must be present in a 10-minute window before the test can be interpreted. - After a contraction stress test, encourage a woman to remain in the health care facility for about 30 minutes, to be certain that contractions have quieted and preterm labor is not a risk. ## CONTRACTION STRESS TEST - **Negative (normal)** - if no fetal heart rate decelerations are present with contractions. - **Positive (abnormal)** - if 50% or more of contractions cause a late deceleration - Deceleration a dip in fetal heart rate that occurs toward the end of a contraction and continues after the contraction ## ULTRASONOGRAPHY - Measures the response of sound waves against solid objects. - A much-used tool in modern obstetrics. - Uses: - Diagnose pregnancy as early as 6 weeks' gestation - Confirm the presence, size, and location of the placenta and amniotic fluid - Establish that a fetus is growing and has no gross anomalies, such as hydrocephalus, anencephaly, or spinal cord, heart, kidney, and bladder defects - Establish sex if a penis is revealed - Establish the presentation and position of the fetus - Predict maturity by measurement of the biparietal diameter of the head - Can also be used to discover complications of pregnancy, such as the presence of a intrauterine device, hydramnios or oligohydramnios, ectopic pregnancy, missed miscarriage, abdominal pregnancy, placenta previa, premature separation of placenta, coexisting uterine tumors, multiple pregnancy, or genetic disorders such as Down syndrome. - Fetal anomalies such as neural tube disorders, diaphragmatic hernia, or urethral stenosis also can be diagnosed. ## AMNIOCENTESIS - From the Greek word amnion for "sac" and kentesis for "puncture". - The aspiration of amniotic fluid from the pregnant uterus for examination. - Typically scheduled between the 14th and 16th weeks of pregnancy to allow for a generous amount of amniotic fluid to be present. - The technique can be used again near term to test for fetal maturity. - Technically easy procedure, but can be frightening to a woman. - Fetal risk: less than 0.5% - Fetal complications: - hemorrhage from penetration of the placenta - infection of the amniotic fluid - puncture of the fetus - irritation of the uterus premature labor - In preparation for amniocentesis, ask the woman to void. - *Rationale: reduce the size of the bladder and prevent an inadvertent puncture. Place her in a supine position on an examining table and drape her appropriately, exposing only her abdomen. Place a folded towel under her right buttock to tip her body slightly to the left.* - Attach fetal heart rate and uterine contraction monitors. - Take her blood pressure and measure the fetal heart rate for baseline levels. - An ultrasound is then done to determine the position of the fetus and the location of a pocket of amniotic fluid and the placenta. - The abdomen is then washed with an antiseptic solution, and a local anesthetic is injected. - Caution the woman that she may feel a sensation of pressure as the needle used for aspiration, a 3- or 4-in, 20- to 22-gauge spinal needle, is introduced. - *!!! Do not suggest that she take a deep breath and hold it as a distraction against discomfort.* - *Rationale: This lowers the diaphragm against the uterus and shifts intrauterine contents.* - The needle is inserted until it reaches the amniotic cavity and a pool of amniotic fluid, carefully avoiding the fetus and placenta. - Syringe is attached, and about 15 mL of amniotic fluid is withdrawn. - The needle is then removed, and the woman rests quietly for about 30 minutes. - Observe fetal heart rate and uterine contractions during and after the procedure. ## SUMMARY - Various methods to assess fetal growth and development include fundal height, fetal movement, fetal heart tones, ultrasonography, magnetic resonance imaging, maternal serum alpha-fetoprotein, amniocentesis, percutaneous umbilical blood sampling, amnioscopy, and fetoscopy. - A biophysical profile is a combination of fetal assessments that predicts fetal well-being better than measuring single parameters.