Obstetrics: Key Terms and Definitions

Key Obstetrics Terms

• Antepartum: the period before delivery and during pregnancy
• Gestation: 40 weeks pregnant
• 1st trimester: 0-13 weeks (from last menstrual period)
• 2nd trimester: 14-26 weeks
• 3rd trimester: 27 weeks until delivery
• Labor: cervical changes with regular/rhythmic contractions
• Intrapartum: the period during delivery
• Postpartum: the period after delivery of the baby and placenta
• GTPAL:
• Gravidity: the number of pregnancies (twins, triplets count as 1)
• Term Births: the number of births at term (longer than 37 weeks)
• Preterm births: births between 20-37 weeks gestation (twins, triplets count as 1)
• Abortions: pregnancies less than 20 weeks of gestation
• Living Children: the number of current living children
• Naegele's Rule: used to calculate the Expected Date of Delivery (EDD)
• Calculation: Date of last menstrual period - 3 months + 7 days + 1 year = EDD

Infertility and Contraception Basics

• Infertility: the inability to get pregnant after 1 year of trying, or after 6 months if the woman is 35 years or older
• Infertility affects 12-15% of reproductive-age couples
• Four goals in infertility care:
• Provide accurate information
• Assist in identifying the cause
• Offer emotional support
• Guide and educate about treatment options
• Contraception: the intentional prevention of pregnancy, using devices or practices to reduce conception risk

Factors Associated with Infertility

• Hormonal factors: pituitary or hypothalamic hormone disorders (like PCOS, causing irregular ovulation)
• Tubal factors: occluded or malformed tubes, untreated STIs leading to scar tissue, congenital absence of tubes, ectopic pregnancies resulting in adhesions and endometriosis
• Uterine factors: developmental anomalies, tumors (benign or cancerous), or endometritis; previous surgeries or infections
• Vaginal/cervical factors: acidic vaginal pH (unfavorable for sperm survival); alkaline pH supports sperm and forms the endocervical mucus plug
• Male infertility: poor sperm quality, structural or hormonal disorders (undescended testes, low testosterone, hypopituitarism, endocrine disorders), genetic disorders (Klinefelter syndrome), decreased libido (heroin/methadone), impotence

Infertility Treatment Options

• Assessment: includes both male and female evaluations, pelvic examination, hormone analysis, ultrasonography, endometrial biopsy, laparoscopy, semen analysis, and hysteroscopy
• Therapeutic procedures:
• Nonmedical: lifestyle changes, alternative methods (herbal remedies, exercise, yoga, stress management)
• Medical therapy: ovarian stimulation medications (clomiphene citrate & Letrozole), antimicrobials (for infections)
• Assisted Reproductive Technologies:
• In-vitro fertilization-embryo transfer: eggs fertilized in lab and implanted in the uterus (best for endometriosis patients)
• Gamete intrafallopian transfer (GIFT): oocytes and sperm placed in fallopian tubes for natural fertilization via laparoscopy
• Zygote intrafallopian transfer (ZIFT): egg fertilized with sperm in vitro, zygote transferred to fallopian tube
• Therapeutic donor insemination (TDI): donor sperm used for impregnation
• Intrauterine insemination: sperm injected into the uterus during ovulation
• Reproductive alternatives: surrogacy and adoption; fallopian tubes may be cut, burned, or blocked

Tubal Ligation

• Tubal ligation: sterilization via bilateral tubal ligation
• Surgical procedure: cutting, burning, or blocking fallopian tubes with bands or clips to prevent sperm-egg fertilization. Highly reversible.
• Using federal funding procedures: patient must be at least 21, provide informed consent, and wait 30 days after consent
• Advantages: permanent and immediate contraception with no impact on sexual function; reduced ovarian cancer risk and can be done within 24-48 hours after childbirth
• Disadvantages: risk of infection, hemorrhage, trauma, irreversible, and doesn't protect against STIs

Fetal Growth and Development Milestones

• Cell Division & Conception:
• Ovum: from ovulation to fertilization
• Zygote: from fertilization to implantation (conception-day 14)
• Embryo: day 15-8 weeks, organ formation, greatest vulnerability
• Fetus: 9 weeks to birth
• Age of viability: ~20 weeks (when interrupting pregnancy and baby needs to be delivered asap)
• Fertilization: the union of ovum and sperm
• Implantation: contact between developing structure and uterine endometrium, approx 6-10 days post-fertilization; ovum meets sperm, becomes a zygote
• After day 14, the zygote becomes an embryo with organs forming
• Fetus: From 9 weeks until birth

Embryonic Development

• Cells align into 3 primary layers
• Ectoderm: outer layer, forms skin, nervous system, external body parts
• Mesoderm: middle layer; forms circulatory, urinary, reproductive organs, muscles, and bones
• Endoderm: inner layer, forms thymus, thyroid, digestive, respiratory, and GU system parts

Developmental Milestones

• Embryonic stage (week 3 to week 8 after fertilization)
• 3 weeks: heart starts beating and blood circulates
• 4 weeks: 2-chamber heart forms a 4-chamber heart; respiratory system begins
• 5 weeks: umbilical cord developed
• 8 weeks: testes and ovaries distinguishable
• Fetal Stage: begins at week 9 until birth
• 9 weeks: fingers, toes, eyelids, nose, and jaw are evident
• 12 weeks: placenta complete; gender is distinguishable; organ systems complete; fetus urinates in amniotic fluid
• 16 weeks: meconium in bowel
• 20 weeks: hearing develops; quickening (mom feels movements); lanugo covers the body; wake/sleep cycles evident
• 24 weeks: circulation visible, rapid brain growth, hiccups, vernix caseosa is thick
• 28 weeks: eyes open & close; process sights & sounds; taste buds developing; hair on the head
• 32 weeks: fingernails, toenails, & fingerprints present; subcutaneous fat develops; vigorous fetal movement
• 36 weeks: lanugo disappearing; amniotic fluid decreases
• 40 weeks: fetal development complete

Hormones During Pregnancy

• Human Chorionic Gonadotropin (hCG): maintains corpus luteum production of estrogen and progesterone until placenta takes over
• Progesterone: decreases FSH/LH secretion, maintains pregnancy by relaxing smooth muscles, decreases uterine contractility, increases fat deposits, decreases insulin ability, maintains pregnancy
• Estrogen: decreases FSH/LH secretion, maintains pregnancy by relaxing smooth muscles, decreasing uterine contractility, increasing fat deposits, decreasing the ability to use insulin, and is associated with skin changes
• Prolactin: prepares breast for lactation
• Oxytocin: stimulates uterine contractions and milk ejection from breasts
• Human Chorionic Somatomammotropin (hCS): growth hormone, promotes breast development, decreases glucose metabolism, increases fatty acids
• Insulin: increased production to compensate for placental hormone-caused insulin resistance
• Cortisol: increases insulin production and peripheral resistance to insulin.
• Diagnosis of pregnancy: presumptive, probable, and positive signs

Signs of Pregnancy

• Presumptive (Subjective): Suggestive signs: missed period, breast changes, nausea & vomiting, fatigue, quickening
• 3-4 weeks: breast changes (other cause: premenstrual changes, oral contraception)
• 4 weeks: amenorrhea (other cause: stress, vigorous exercise, endocrine problems, malnutrition)
• 4-14 weeks: nausea & vomiting (other cause: GI virus, food poisoning)
• 6-12 weeks: urinary frequency (other cause: infection, pelvic tumors)
• 12 weeks: fatigue (other cause: stress, illness)
• 16-20 weeks: quickening (other cause: gas, peristalsis)
• Probable (Objective): Examiner-observed changes
• 5 weeks: sign (other cause: pelvic congestion)
• 6-8 weeks: Chadwick sign (other cause: pelvic congestion)
• 6-12 weeks: Hegar sign (other cause: pelvic congestion)
• 4-12 weeks: positive serum pregnancy test (other cause: Hydatidiform mole, choriocarcinoma)
• 6-12 weeks: positive urine pregnancy test (other cause: false-positive, pelvic infection, tumors)
• 16 weeks: Braxton Hicks contractions (other cause: myomas, other tumors)
• 16-28 weeks: ballottement (other cause: tumors, cervical polyps)
• Positive (Objective): Examiner-observed confirmation
• 5-6 weeks: visualization of fetus by real-time ultrasound
• 6 weeks: Fetal heart tones (FHT) detected by ultrasound
• 16 weeks: Visualization of fetus by radiographic study
• 8-17 weeks: FHT detected by Doppler ultrasound stethoscope
• 17-19 weeks: FHT detected by fetal stethoscope
• 19-22 weeks: fetal movements palpated
• Later in pregnancy: fetal movements visible

Teratogens and Teen Pregnancy

• Teratogens: environmental factors causing embryo/fetus abnormalities
• First 3 months: critical for embryonic/fetal development; teratogens have greatest impact (days 15-60)
• Smoking, lead, lithium, rubella, syphilis, cocaine, varicella, drugs, chemicals, infection, radiation, maternal conditions, and malnutrition
• Teen pregnancy: Pregnancy in those 16 or younger introduces stress; teens lack financial resources or maturity to avoid teratogens/seek prenatal care
• Children of teen mothers may be at risk for neglect/abuse due to inadequate knowledge; teens need double the nutrition and may hide pregnancy

Umbilical Cord

• Umbilical Cord: 2 cm diameter, 20-90 cm length at term
• Wharton's Jelly: connective tissue surrounding the vessels to prevent compression and ensure nourishment
• Nuchal Cord: when the cord is wrapped around the fetal neck
• Week 3: blood vessels develop to supply the embryo with maternal nutrients/oxygen
• Week 5: the embryo curves inward from both ends connecting the stalk to the ventral side
• Arteries: two arteries carry deoxygenated blood from the embryo to the chorionic villi
• Vein: one vein returns oxygenated blood to the embryo

Amniotic Fluid

• Amniotic Fluid: 700-1000mL at term (normal volume); maternal fluid/baby's urine/lung fluid; derived from maternal fluids by diffusion
• Maintains constant fetal body temperature, serves as oral fluid source/respiratory waste, maintains fluid and electrolyte balance; fetus swallows fluid, which travels in/out of fetal lungs; fetus urinates (11 weeks)
• Allows freedom of movement for musculoskeletal development and provides resistance
• Cushions the fetus from trauma by outside forces
• Facilitates symmetric growth, prevents tangling with membranes
• Provides auditory stimulation via blood flow sounds
• Contains antibacterial factors (transferrin, fatty acids, immunoglobulins, lysosome) for infection protection
• Low fluid (<300 mL) can indicate fetal renal abnormalities; high fluid (>2 L) is associated with GI and other malformations

Placenta

• Placenta: maternal-placental-embryonic circulation by day 17, embryonic heart begins beating; means of metabolic exchange, complete by week 12
• Endocrine function: produces 4 hormones to maintain pregnancy/support fetus
• hCG detected 8-10 days post-conception; preserves the function of the corpus luteum and continues the supply of estrogen & progesterone
• Human placental Lactogen (hPL): stimulates maternal metabolism for fetal growth
• Metabolic Function: respiration, nutrition, excretion, and storage
• Functions as lungs for fetus; oxygen diffuses from maternal to fetal blood; carbon dioxide diffuses opposite
• Stores carbohydrates, protein, calcium, and iron to meet fetal needs
• Circulatory effects

Nutrition During Pregnancy

• Folate and folic acid: Prevents neural tube defects
• Increase caloric intake (increase of +340/day during 2nd trimester and +452/day during 3rd trimester)
• Increase protein!
• Consume leafy vegetables, dried peas/beans, seeds, orange juice, breads, cereals, and other grains (600 mcg folic acid)
• Consume fat and water-soluble vitamins
• Iron and calcium supplements
• Drink fluids: 8-10 glasses a day (2.3 L) of water and fruit juice
• Limit caffeine (fewer than 300 mg/day and avoid alcohol)
• At Risk Patients: adolescents, those with poor nutritional habits, those who do not consume enough protein, calcium, iron, or vitamin B12, and those who experience nausea and vomiting

Weight Gain During Pregnancy

• Weight Gain: the average patient should gain 25-35 lbs
• 2-4 lbs per month during the first trimester
• 1 lb per week during the last 2 trimesters
• Normal BMI: 25-35 lbs
• Underweight: 28-40 lbs
• Overweight: 15-25 lbs
• Look for food allergies and special dietary practices

Physiological Changes During Pregnancy

• Reproductive System (Uterus): increases in size/shape/position by week; changes in contractility (Braxton Hicks); changes related to fetus (ballottement, quickening); cervical changes
• Uterine Changes: fundal height measures fetal well-being
  • McDonald's Rule (18-30 weeks): fundal height (cm) = weeks gestation + 2 weeks; also measured via ultrasound
• Breast Changes: fullness, heaviness, heightened sensitivity, areolae darken, striae gravidarum, colostrum

Body Systems During Pregnancy

• Cardiovascular System:
• Cardiac Output increases by 30-50%
• Blood volume: increases 30-45% at term
• Pulse: increases 10-15/min
• Watch for Supine Hypotension Syndrome: pressure from pregancy advances and the weight of the uterus presses on abdominal vessels, causing low blood pressure
  • Signs: pallor, dizziness, faintness, breathlessness, tachycardia, nausea, clammy skin, sweating
• Increase in RBCs and risk of blood clots
• Respiratory: oxygen needs increase by 20-40%
• GI System: Nausea and Vomiting (NVP; morning sickness); abdominal discomfort; Pica – craving non-nutritive substances
• Musculoskeletal System: increasing weight, postural/gait changes, back pain
• Urinary System: filtration increases, excrete protein & albumin
• Integumentary System: Melasma (chloasma or mask of pregnancy); linea nigra; striae gravidarum; palmar erythema (related to increased estrogen levels)
• Endocrine System: Thyroid (T3/T4 levels increase; T4 important for fetal CNS); pituitary gland (enlarges); pancreas (insulin needs increase)

Fetal Assessment

• Key goals are to determine fetal well-being, estimate growth/gestational age, and prevent unnecessary interventions
• Biophysical Assessment (Noninvasive): Uses technology or physical assessment
• Biophysical profile, nonstress testing, fetal kick count
• It's important for nurses to biophysically assess risks from the mother to the baby
• Abdominal Ultrasound: fetal movement of baby's diagram; gross body movement; fetal tone and amniotic fluid volume

Fetal Assessment Measures

• Kick Counts: Active fetus is reassuring; feel 5-6 movements within 30 min-1 hr or 10 movements in 12 hrs; if less than 5, do NST or BPP
• Non-stress Test: Fetal monitoring for 20-30 mins;
• Reactive test = 2+ accelerations (CNS intact) in FHR;
• Nonreactive = more assessments are needed
• Contraction Stress Test (CST): Evaluates fetal response to uterine contractions via nipple stimulation or oxytocin administration
• Results: Negative (normal, absence of late decels); Positive (late decels with more than 50% contractions; suggests uteroplacental insufficiency)
• Biochemical Assessment: uses blood, body fluid or tissue samples; Fetal aneuploidy screening, amniocentesis (of amniotic fluid), chorionic villus sampling

Biochemical Assessment Procedures

• Amniocentesis: invasive, ultrasound-guided needle through the abdomen into the uterus to get amniotic fluid After 15 weeks, to detect lung maturity, genetic abnormalities through alpha-fetoprotein; and empty bladder prior to the procedure. Monitor VS, FHR, and uterine contractions for 30 minutes after procedure
• Chorionic Villus Sampling (CVS): Performed at 10-13 weeks (1st trimester) Assess developing placenta via sterile syringe and needle inserted through the abdomen of vagina under ultrasound guidance
• Maternal Serum Alpha-Fetoprotein (MSAFP): Mom's blood sample tested at 15-20 weeks gestation; elevated levels may indicate neural tube defects, so follow up with targeted ultrasound or amniocentesis

Additional Fetal Assessment Tests

• Indirect Coombs's Test: Screens for Rh incompatibility via mom's blood test
• If mom has antibodies against Rh+ blood, the baby is at risk of hemolytic anemia
• Mom with Rh- blood (O-, B-, AB-, A-) and a Rh+ fetus can lead to mom identifying the fetus blood as foreign body and developing antibodies against it.
• 1st pregnancy fetus won't be affected; 2nd pregnancy at risk

Gestational Diabetes Mellitus (GDM)

• GDM: Glucose intolerance onset during pregnancy; maternal and fetal risks (normal value 5-6%)
• Care management: early pregnancy screen (24-28 weeks gestation); physical exam, lab tests (baseline renal function, UA and culture, & Glycosylated hemoglobin A1C)
• Antepartum interventions: diet & exercise; insulin if needed; self-monitoring of glucose levels, urine testing, pharmacologic therapy which may require hospitalization or fetal surveillance

GDM Maternal and Fetal Risks, & Interventions

• Maternal risks: high blood pressure, frequent UTIs, preeclampsia, ketoacidosis, labor dystocia, C-section birth, hyperglycemia & hydramnios
• Fetal Risks: congenital anomalies, birth injuries, hypoglycemia, respiratory distress syndrome; increased death risk; macrosomia, premature birth, premature rupture of membranes (PROM)
• Interventions: During labor, monitor glucose hourly, use insulin infusions, & avoid dextrose solutions (may require c-section) and postpartum check glucose for risk of type 2 DM
• After birth, most return to normal; high risk for future GDM; increased risk of type 2 DM; reassess at 6-12 weeks; encourage breastfeeding; contraception

Key Pregnancy Complications

• Gestational HTN: common disorder in pregnancy reported during pregnancy; develops in 2nd/3rd trimester, with systolic blood pressure > 140 mmHg or diastolic blood pressure > 90 mmHg, or both recorded on 2+ occassions, without proteinuria after 20th week of pregnancy
• chronic HTN: HTN in the 1st trimester (< 20 weeks)
• Preeclampsia: HTN after 20 weeks gestation, with proteinuria, rising BP, and edema in extremities. Can also be with severe headaches and RUQ or epigastric pain

Preeclampsia Pathology, Risk Factors and Eclampsia

• Preeclampsia Pathology: Root cause is placenta; defective spiral artery remodeling causing systemic vasoconstriction & endothelial dysfunction
• Preeclampsia Risk Factors: History in previous pregnancies, family history, 1st pregnancy is obesity, old/very young age, medical conditions
• Eclampsia: gestational HTN, proteinuria, AND seizure activity/coma
• HELLP Syndrome (Hemolysis, Elevated Liver Enzymes, Low Platelets): diagnosed by labs; more in white women; increases for maternal death and adverse perinatal outcomes

Risks, Care and Symptoms of HELLP Syndrome

• HELLP: Is associated with increased risk for pulmonary edema, acute renal failure, DIC, placental abruption, liver hemorrhage, ARDS, sepsis, and stroke
• HELLP: is managed with expectant management, perinatologist services, antihypertensives/corticosteroids/intrapartum care/magnesium sulfate and control their BP
• Assess the patient via BP measurement

Placenta Previa

• Placenta Previa: Placenta implantation is in lower uterine segment near/over internal cervical os; classification based on the degree of coverage of the internal cervical os
• The placenta should normally implant in the upper part of the uterus
• Classification I: complete placenta previa (completely covers the cervix)
• Classification II: marginal placenta previa (partially covering cervix)
• Classification III: low-lying placenta previa (doesn't cover cervix, but in the lower right or left side of uterus)
• Placenta Previa: will show up and is painless
• The bright red vaginal bleeding will show
• The Fundal height is bigger than normal
• Do not do perform vaginal exams

Placental & Other Pregnancy Complications

• Placental Abruption (Premature Separation of the Placenta)
• CMS: sudden onset of uterine pain, dark-red vaginal bleeding, fetal distress
• Diagnosis for confirmation: ultrasound for fetal well-being & placenta
• Management: depends on the degree of abruption; assess FHR pattern; IV fluids, blood products, and meds; O2, V/S, U/O
• It is more dangerous to leave it until after baby's birth
• Hyperemesis Gravidarum: Excessive vomiting with dehydration, electrolyte imbalance, ketosis, and more.
  • CMS: excessive vomiting, dehydration, increased pulse rate, and decreased blood pressure

Ectopic Pregnancy

• Ectopic Pregnancy: Fertilized ovum implantation is outside of the uterine cavity (mostly in the fallopian tube)
• CMS: abdominal pain, delayed menses, abnormal vaginal bleeding (spotting)
• Diagnosis: quantitative hCG levels, transvaginal ultrasound
• Medical management: Methotrexate (to end the pregnancy)
• Surgical: salpingectomy (removal of the entire fallopian tube)