Pregnancy, Childbirth & Puerperium

Routine prenatal care: schedule and risk assessment

Clinical Overview and When to Initiate Prenatal Care

— Preconception counseling: folic acid 400–800 mcg/day (4 mg if prior NTD, diabetes, antiepileptics), optimize glycemic control (A1c <6.5%), review teratogenic meds (ACEi/ARB, warfarin, valproate, isotretinoin, methotrexate), update vaccines, screen STIs.

— Every 4 weeks until 28 weeks

— Every 2 weeks from 28–36 weeks

— Every 1 week from 36 weeks to delivery

— Total ~12–14 visits; group/telehealth hybrid models acceptable for low-risk patients.

Step 3 management: At the initial visit, order: CBC, blood type & Rh with antibody screen, rubella & varicella immunity, HBsAg, HIV, syphilis (RPR/VDRL), chlamydia/gonorrhea (if ≤25 or risk factors), urine culture, urine protein, Pap if due, TSH if symptomatic/high-risk, and offer aneuploidy screening options. Hepatitis C screening is now universal in every pregnancy (CDC/ACOG 2021).

Board pearl: A patient with uncertain LMP and a first-trimester CRL — use the ultrasound EDD; do not "average" with LMP. Accurate dating prevents inappropriate post-dates induction and iatrogenic prematurity. Re-dating later in pregnancy is far less reliable, so lock the EDD early and do not change it based on later scans unless clinically compelling.

Goal of prenatal care: structured longitudinal surveillance to optimize maternal and fetal outcomes through risk stratification, screening, immunization, counseling, and timely intervention.

Ideal timing of first visit: within the first trimester, ideally 6–10 weeks gestation; earlier (preconception) if known comorbidities.

Standard ACOG visit cadence (uncomplicated pregnancy):

Dating the pregnancy: LMP confirmed by first-trimester ultrasound (CRL) is the most accurate; redating per ACOG criteria if discrepancy exceeds tolerance (e.g., >7 days in first trimester).

Establish EDD early — it anchors every subsequent screening window (NT, aneuploidy serum, anatomy scan, GDM screen, GBS, post-dates management).

Presentation Patterns and Key History at the Initial Visit

— Obstetric history (GTPAL): gravidity, term, preterm, abortions, living. Document prior cesareans, shoulder dystocia, preeclampsia, GDM, PPH, preterm birth, stillbirth, cervical insufficiency.

— Medical: HTN, diabetes, thyroid disease, asthma, SLE/APS, seizure disorder, DVT/PE, depression, prior bariatric surgery.

— Surgical: uterine surgery (myomectomy, classical cesarean, cone biopsy/LEEP).

— Medications: review for teratogens and OTC/herbal use; switch ACEi→labetalol/nifedipine, warfarin→LMWH, SSRI risk-benefit discussion.

— Family history: genetic disease, consanguinity, ethnicity-based carrier screening (CF, hemoglobinopathies, SMA, Tay-Sachs, fragile X).

— Social: tobacco, alcohol, cannabis, opioids, IPV screening (privately, partner absent), housing, occupation, exposures.

— Age <17 or ≥35, BMI ≥30 or <18.5, chronic HTN, pregestational DM, prior preterm birth, prior preeclampsia, multiple gestation, ART conception, prior stillbirth, autoimmune disease, thrombophilia.

Key distinction: USPSTF aspirin recommendation uses ≥1 high-risk OR ≥2 moderate-risk; do not wait until BP elevates — this is primary prevention, started by 16 weeks ideally, no later than 28 weeks.

Board pearl: Always screen for intimate partner violence privately at the first visit and at least once each trimester; pregnancy is a peak window for escalation of IPV and homicide is a leading cause of maternal death.

Presenting symptoms suggesting pregnancy: amenorrhea, breast tenderness, nausea/vomiting, urinary frequency, fatigue — confirmed with urine or serum β-hCG.

Comprehensive history components:

Risk stratification triggers for "high-risk" prenatal track:

Aspirin 81 mg daily from 12–28 weeks (continued to delivery) for preeclampsia prevention if ≥1 high-risk factor (prior preeclampsia, chronic HTN, DM, renal disease, autoimmune, multiples) or ≥2 moderate-risk factors (nulliparity, BMI >30, age ≥35, family history, Black race, low SES).

Physical Exam and Vital Signs Across Trimesters

— Baseline BP, height, weight, BMI — anchors GWG target and HTN diagnosis.

— Thyroid, cardiac (systolic flow murmur is physiologic), pulmonary, breast, abdominal exam.

— Pelvic exam: speculum for Pap (if due) and STI swabs; bimanual to assess uterine size vs dates.

— Clinical pelvimetry is no longer routine.

— Blood pressure — screen for gestational HTN/preeclampsia.

— Weight — track gestational weight gain (GWG).

— Fundal height in cm from 20–36 weeks should approximate gestational age ±2 cm; discrepancy >3 cm → ultrasound for growth, fluid, or fetal lie.

— Fetal heart tones by Doppler from ~10–12 weeks (normal 110–160 bpm).

— Fetal movement inquiry from ~24 weeks; formal kick counts from 28 weeks in high-risk patients.

— Leopold maneuvers from ~36 weeks to assess presentation; confirm with ultrasound if breech for ECV at 37 weeks.

— Underweight (BMI <18.5): 28–40 lb

— Normal (18.5–24.9): 25–35 lb

— Overweight (25–29.9): 15–25 lb

— Obese (≥30): 11–20 lb

— Twins (normal BMI): 37–54 lb.

— ↑ plasma volume 40–50%, ↑ CO 30–50%, ↓ SVR, ↓ BP nadir at 24–28 weeks then rises, mild tachycardia (~15 bpm), dilutional anemia, mild respiratory alkalosis with compensatory ↓ HCO3.

Step 3 management: Two BPs ≥140/90 at least 4 hours apart after 20 weeks = gestational hypertension; add proteinuria (≥300 mg/24h or P/Cr ≥0.3) or severe features → preeclampsia. Severe-range BP ≥160/110 requires acute treatment with IV labetalol, IV hydralazine, or oral nifedipine within 30–60 minutes.

Board pearl: Pregnant patient with lower-extremity edema and a systolic flow murmur is overwhelmingly physiologic; an S3 is normal, but S4, diastolic murmur, or symptomatic murmur warrants echo.

Initial visit exam:

Follow-up visit exam (every visit after ~12 weeks):

Gestational weight gain targets (IOM):

Hemodynamic adaptations of pregnancy to recognize as physiologic, not pathologic:

First-Trimester Labs, Imaging, and Screening

— CBC (anemia, thrombocytopenia)

— Blood type, Rh, antibody screen — Rh-negative patient with negative screen receives anti-D immunoglobulin (RhoGAM) at 28 weeks and within 72 hours postpartum if neonate Rh-positive.

— Rubella IgG, varicella IgG — if non-immune, vaccinate postpartum (live vaccines contraindicated in pregnancy).

— HBsAg, HIV (opt-out), syphilis (RPR/VDRL), HCV (universal as of 2021).

— Gonorrhea/chlamydia NAAT if ≤25 or risk factors.

— Urine culture to detect asymptomatic bacteriuria → treat to prevent pyelonephritis/preterm labor.

— Urine protein dipstick (baseline).

— Pap smear if due per age-based guidelines.

— TSH only if symptomatic or high-risk (not universal).

— Hemoglobin electrophoresis if African, Mediterranean, SE Asian descent or low MCV.

— Cell-free DNA (cfDNA/NIPT) from 10 weeks — highest sensitivity/specificity for T21, T18, T13; also fetal sex/Rh.

— Combined first-trimester screen (11–13+6 wk): NT + PAPP-A + β-hCG.

— Quad screen (15–22 wk): AFP, hCG, estriol, inhibin A — useful if late to care; AFP also screens NTDs.

— Integrated/sequential screens combine first + second trimester.

— CVS at 10–13 weeks or amniocentesis at ≥15 weeks.

Key distinction: Screening tests (cfDNA, quad) give risk estimates; diagnostic tests (CVS, amnio) give karyotype/microarray. A positive cfDNA still requires confirmatory diagnostic testing before irreversible decisions — false positives occur, especially with confined placental mosaicism and vanishing twins.

Board pearl: Elevated MSAFP → think open NTD, abdominal wall defect, multiples, or wrong dates. Low MSAFP with low estriol and high hCG/inhibin A → trisomy 21.

Universal first-visit labs (Step 3 must-orders):

Aneuploidy screening — offer to ALL patients regardless of age:

Diagnostic testing (offered if screen positive or high a priori risk):

First-trimester ultrasound (ideal 10–13 weeks): confirms viability, dating by CRL, number/chorionicity, NT measurement.

Second- and Third-Trimester Screening Studies

— Quad screen (if not already done via cfDNA/first-tri).

— Offer amniocentesis if indicated.

— Anatomy ultrasound — structural survey, placental location, cervical length, fetal sex.

— Cervical length <25 mm in singleton with prior preterm birth → vaginal progesterone ± cerclage consideration.

— 1-hour 50-g GLT for GDM; if ≥140 mg/dL → 3-hour 100-g OGTT (Carpenter-Coustan: fasting 95, 1h 180, 2h 155, 3h 140; two abnormal values = GDM).

— Early GDM screen at first visit if BMI ≥30, prior GDM, prior macrosomia, PCOS, family history.

— Repeat CBC for anemia.

— Antibody screen in Rh-negative patients before RhoGAM.

— Tdap vaccine at 27–36 weeks every pregnancy.

— Anti-D immunoglobulin to all Rh-negative, antibody-negative patients.

— Group B Streptococcus vaginal-rectal swab; if positive → intrapartum penicillin prophylaxis (cefazolin if non-anaphylactic PCN allergy; clindamycin only if susceptibility confirmed, otherwise vancomycin).

— Repeat HIV, syphilis, GC/CT if high-risk.

— Give: Tdap (every pregnancy), influenza (any trimester), COVID-19, RSV (maternal at 32–36 wk Sept–Jan).

— Avoid (live): MMR, varicella, LAIV, HPV.

Step 3 management: A patient with prior spontaneous preterm birth gets cervical length surveillance every 2 weeks from 16–24 weeks and is offered vaginal progesterone; 17-OHP (Makena) was withdrawn from market in 2023 — do not select it on the exam if updated answer choices exist.

CCS pearl: When a Step 3 CCS case shows a 26-week prenatal visit, order 1-hr GLT, CBC, antibody screen if Rh-neg, then advance clock — RhoGAM and Tdap are queued for week 28 and 27–36 respectively.

15–20 weeks:

18–22 weeks:

24–28 weeks:

28 weeks:

35–37 weeks:

Vaccines in pregnancy:

Antenatal testing (NST/BPP) from 32 weeks in high-risk pregnancies (chronic HTN, DM, IUGR, post-dates, decreased fetal movement).

Risk Stratification: Routing Patients to Standard vs High-Risk Care

— Maternal: pregestational DM, chronic HTN on multiple agents, CKD, SLE, APS, thrombophilia, congenital/acquired heart disease, prior PE/DVT, HIV, organ transplant, hemoglobinopathy, severe mental illness, opioid use disorder.

— Obstetric history: recurrent pregnancy loss, prior stillbirth, prior severe preeclampsia <34 wk, prior preterm birth <34 wk, prior placental abruption, prior cesarean (especially classical), placenta accreta spectrum risk.

— Current pregnancy: multiples, IUGR, polyhydramnios/oligohydramnios, fetal anomalies, GDM A2, isoimmunization, cervical insufficiency, placenta previa/accreta.

— Start low-dose aspirin 81 mg between 12 and 16 weeks, continue through delivery, in patients with ≥1 high-risk or ≥2 moderate-risk factors.

— Prenatal vitamin with iron 27 mg, folic acid 400–800 mcg, iodine 150 mcg, calcium 1000 mg, vitamin D 600 IU.

— Avoid: high-mercury fish (shark, swordfish, king mackerel, tilefish), unpasteurized dairy, deli meats unless heated, raw shellfish, excess vitamin A (>10,000 IU).

Board pearl: A patient with chronic hypertension and pregestational diabetes is in both USPSTF high-risk categories — they qualify for low-dose aspirin even with no other factors, and they require early GDM screening, baseline 24-hour urine protein, baseline labs, retinal exam, and serial growth scans from ~28 weeks.

Key distinction: "Advanced maternal age" alone (≥35) is a moderate-risk factor for preeclampsia and an indication to offer (not mandate) aneuploidy diagnostic testing; it does not by itself mandate MFM referral.

Standard-risk track: uncomplicated singleton, no chronic disease, BMI 18.5–29.9, age 17–34, no prior adverse OB outcomes → standard ACOG cadence with primary OB/family medicine/midwifery care.

High-risk indications for MFM co-management or referral:

Preeclampsia prevention algorithm (USPSTF/ACOG):

VTE risk assessment each trimester; consider prophylactic LMWH in patients with prior VTE or high-risk thrombophilia.

Nutrition and supplementation baseline:

Pharmacotherapy and Supplementation in Routine Prenatal Care

— Standard: 400–800 mcg/day preconception through first trimester minimum.

— High-dose 4 mg/day if prior NTD-affected pregnancy, pregestational diabetes, on antiepileptics (valproate, carbamazepine), or sickle cell disease.

— Routine prenatal vitamin contains 27 mg; supplement to 60–120 mg elemental iron daily if iron-deficiency anemia (Hgb <11 g/dL T1/T3, <10.5 T2).

— Pyridoxine (B6) 10–25 mg q6–8h ± doxylamine 12.5 mg → Diclegis is first-line.

— Add ondansetron (after first trimester preferred; small absolute risk of cleft palate discussed), promethazine, or metoclopramide.

— Hyperemesis gravidarum: admit if dehydration, ketonuria, weight loss >5%; IV fluids with thiamine before dextrose, IV antiemetics, consider methylprednisolone if refractory after 10 weeks.

— ACEi/ARB → switch to labetalol, nifedipine, methyldopa, hydralazine.

— Warfarin → LMWH (preferred) or UFH.

— Statins — discontinue (recent FDA softening, but typically held).

— Valproate → switch antiepileptic preconception with neurology.

— Isotretinoin, methotrexate, mycophenolate → contraindicated.

— At 28 weeks, within 72 hours postpartum if neonate Rh-positive, after any sensitizing event (bleeding, trauma, amnio, ECV, abortion, ectopic).

Step 3 management: Pregnant patient on lisinopril for chronic HTN presenting at 8 weeks → stop ACEi immediately, start labetalol 200 mg BID (target BP <140/90 in pregnancy per ACOG 2022; lower thresholds reduce severe HTN without harming fetus per CHAP trial).

Board pearl: CHAP trial (2022) changed practice — treat chronic HTN in pregnancy to BP <140/90 rather than the old "permissive" threshold of 160/105.

Folic acid:

Iron:

Calcium and vitamin D: 1000 mg and 600 IU daily; vitamin D supplementation if deficient.

Aspirin 81 mg daily for preeclampsia prophylaxis (see chunk 6).

Antiemetics for NVP (stepwise):

Common teratogens to STOP at confirmation of pregnancy:

Vaccines (see chunk 5) — Tdap, flu, COVID, RSV given in pregnancy; live vaccines deferred.

Rh immunoglobulin (RhoGAM 300 mcg):

Counseling, Anticipatory Guidance, and Lifestyle Modification

— Additional ~340 kcal/day in T2, ~450 kcal/day in T3 for singleton; ~600 kcal/day for twins.

— Protein 1.1 g/kg/day; emphasize fruits, vegetables, whole grains, lean protein, low-mercury fish (2–3 servings/wk).

— Avoid: alcohol (no safe amount), unpasteurized cheese/milk, raw eggs, raw fish/sushi, deli meats unless steamed, pâté, raw sprouts, high-mercury fish, excess caffeine (>200 mg/day).

— Alcohol — none; FAS risk.

— Tobacco — counsel and offer NRT in pregnancy after risk-benefit discussion.

— Cannabis — recommend cessation (neurodevelopmental concerns).

— Opioids — do not abruptly taper; refer for buprenorphine or methadone MAT (medication-assisted treatment).

Step 3 management: A patient on chronic opioids for back pain who becomes pregnant — do not stop opioids abruptly (risk of withdrawal, miscarriage, preterm labor); transition to buprenorphine under specialist guidance and coordinate neonatal care for NAS monitoring.

Board pearl: "Listeria avoidance" foods (deli meats, soft cheeses, pâté, raw sprouts) are a recurring exam item — listeriosis causes stillbirth, preterm labor, and neonatal sepsis.

Nutrition:

Exercise: 150 min/week moderate-intensity aerobic activity if no contraindications; avoid contact sports, scuba, supine exercise after T1, hot yoga.

Sexual activity: safe unless placenta previa, PPROM, threatened preterm labor, active bleeding.

Travel: airline travel generally safe up to 36 weeks for uncomplicated singletons; encourage hydration, ambulation, compression stockings for VTE prevention.

Substance use:

Dental care: safe and encouraged; periodontal disease linked to preterm birth.

Seatbelts: lap belt low across hips beneath gravid uterus, shoulder belt between breasts.

Workplace: discuss accommodations; avoid prolonged standing, heavy lifting in late pregnancy if symptomatic.

Labor signs and "when to call": regular painful contractions, ROM, vaginal bleeding, decreased fetal movement, severe headache/visual changes/RUQ pain, BP elevation, fever.

Postpartum planning: contraception choices, breastfeeding intent, depression screening plan, return-to-work timing, "fourth trimester" visit within 3 weeks and comprehensive visit by 12 weeks postpartum.

Special Populations — Advanced Maternal Age and Medical Comorbidities

— Higher risk of aneuploidy, miscarriage, GDM, HTN/preeclampsia, placenta previa, cesarean, stillbirth.

— Offer (don't mandate) diagnostic testing (CVS/amnio); cfDNA acceptable as screening.

— Antenatal testing beginning ~36 weeks for ≥35; 32 weeks for ≥40; consider delivery by 39–40 weeks for ≥40.

— Treat to <140/90 (CHAP trial); preferred agents labetalol, nifedipine XL, methyldopa, hydralazine.

— Baseline labs: CMP, urine P/Cr or 24-hr protein, EKG; serial growth scans from 28 wk; antenatal testing from 32 wk; delivery by 37–39+6 wk depending on control.

— Preconception A1c <6.5%; folic acid 4 mg; switch oral agents to insulin (metformin acceptable in some cases); retinal exam, baseline renal function.

— Early GDM screen, anatomy scan with fetal echo at 20–22 wk (CHD risk), serial growth scans, antenatal testing from 32 wk.

— Deliver 39–40 wk if well-controlled, earlier if vascular complications.

— Hypothyroidism — increase levothyroxine ~25–30% at confirmation, target TSH <2.5 in T1.

— Hyperthyroidism — PTU in T1, methimazole T2–T3 (reverses prior teaching due to PTU hepatotoxicity).

Key distinction: GDM A1 (diet-controlled) does not require antenatal testing or early delivery; GDM A2 (medication-controlled) does — antenatal testing from 32 wk, delivery 39–39+6 wk.

Board pearl: Newly elevated TSH in a pregnant patient with known hypothyroidism almost always means the levothyroxine dose was not increased at pregnancy confirmation — verify and titrate every 4 weeks.

Advanced maternal age (≥35 at delivery):

Chronic hypertension:

Pregestational diabetes (T1DM/T2DM):

Renal impairment (CKD): MFM, baseline GFR, proteinuria, BP; high preeclampsia risk → aspirin; growth scans, antenatal testing; nephrology co-management.

Hepatic disease: baseline LFTs; intrahepatic cholestasis of pregnancy (pruritus + elevated bile acids) — treat with ursodeoxycholic acid, deliver by 36–37 wk if bile acids ≥100 µmol/L.

Thyroid:

Special Populations — Adolescents, Multiples, ART, and Vulnerable Groups

— ↑ risk of preeclampsia, preterm birth, low birth weight, anemia, STIs, depression, IPV.

— Confidentiality and consent vary by state — most allow minors to consent to prenatal care without parental notification.

— Enhanced support: nutrition (calcium, iron, folate), school continuity, social work, contraception counseling for postpartum.

— Determine chorionicity/amnionicity in first trimester — this drives risk and surveillance.

— Mono-chorionic twins: TTTS, TAPS, sIUGR — serial ultrasounds every 2 weeks from 16 wk.

— Di-chorionic: growth scans every 4 weeks.

— Higher GDM, preeclampsia, preterm birth, anemia, PPH risk.

— Delivery timing: di-di 38 wk, mono-di 36–37+6 wk, mono-mono 32–34 wk (often inpatient from 24 wk).

— ↑ multiples, preeclampsia, placenta previa, vasa previa risk; screen carefully on anatomy scan.

— Counsel TOLAC vs ERCD; success ~60–80% in appropriate candidates; classical cesarean = contraindication to TOLAC (uterine rupture risk).

Step 3 management: A 15-year-old presents alone for suspected pregnancy — confirm pregnancy, provide confidential care, screen for IPV/coercion, ask about partner age (statutory rape reporting laws vary), offer all options counseling, and engage social work; do not require parental consent for prenatal services in most states.

Board pearl: Always determine chorionicity before 14 weeks — after this window, the "lambda" and "T" signs become unreliable, and chorionicity drives every subsequent management decision in twins.

Adolescent pregnancy (<17 yr):

Multiple gestation:

ART/IVF pregnancies:

Patients with prior cesarean:

Patients with disabilities: ensure accessible care, appropriate consent processes, lactation/parenting support.

Incarcerated patients: federal law prohibits shackling during labor; ensure prenatal care access.

Refugee/immigrant patients: screen for TB, parasitic infections, hemoglobinopathies; provide interpreter services (use professional interpreter, not family/minors).

LGBTQ+ patients: gender-affirming language; transmasculine pregnant individuals require same prenatal care + sensitivity around dysphoria and chestfeeding decisions.

Complications and Adverse Outcomes to Anticipate

— Spontaneous abortion (10–20% clinically recognized).

— Ectopic pregnancy — rule out with β-hCG trend and TVUS; suspect with abdominal pain, bleeding, hemodynamic instability.

— Gestational trophoblastic disease — markedly elevated hCG, "snowstorm" US, hyperemesis, early preeclampsia.

— Hyperemesis gravidarum.

— Cervical insufficiency (painless dilation) — cerclage if indicated.

— Preterm labor onset, PPROM.

— Fetal anomalies detected on anatomy scan.

— Isoimmunization.

— Preeclampsia / HELLP / eclampsia — BP, proteinuria, headache, visual changes, RUQ pain, thrombocytopenia, hemolysis, transaminitis.

— Gestational diabetes complications: macrosomia, polyhydramnios, shoulder dystocia, neonatal hypoglycemia.

— Preterm labor/birth.

— Placenta previa (painless bleeding), abruption (painful bleeding + uterine tenderness, often with HTN/cocaine/trauma), vasa previa.

— IUGR, oligohydramnios.

— Stillbirth — decreased fetal movement is a red flag, prompt NST/BPP.

— PPH, retained placenta, chorioamnionitis, endometritis, peripartum cardiomyopathy, VTE (highest risk postpartum 6 wk), postpartum depression/psychosis.

— Pregnancy is hypercoagulable; LMWH is treatment (warfarin and DOACs contraindicated antepartum).

— Imaging: compression US for DVT; CTPA or V/Q acceptable for PE — do not withhold imaging for radiation concerns (fetal dose is well below threshold).

Key distinction: Painless third-trimester bleeding → previa (do NOT do a digital exam, get US first). Painful bleeding with rigid/tender uterus → abruption (often concealed; fetal distress out of proportion to visible bleeding).

Board pearl: Severe-feature preeclampsia at any gestational age demands magnesium sulfate, BP control, and delivery at ≥34 weeks; <34 weeks with stable maternal/fetal status → expectant management with steroids in tertiary center.

First trimester:

Second trimester:

Third trimester:

Peripartum:

VTE in pregnancy:

When to Escalate, Refer, or Hospitalize

— Pregestational DM, chronic HTN poorly controlled, CKD, autoimmune disease, cardiac disease, prior severe preeclampsia <34 wk, prior preterm birth <34 wk, multiples, fetal anomalies, isoimmunization, suspected accreta spectrum.

— Positive screen (cfDNA, quad), advanced maternal/paternal age preferences, family history of genetic disorders, consanguinity, recurrent loss, prior anomaly.

— Vaginal bleeding, ROM, regular contractions <37 wk, decreased fetal movement, severe headache, visual changes, RUQ/epigastric pain, BP ≥160/110, dyspnea/chest pain, suspected DVT/PE, trauma (including MVC, falls, IPV), seizure.

— Severe preeclampsia/HELLP/eclampsia, suspected abruption, preterm labor with cervical change, PPROM, pyelonephritis (admit IV antibiotics in pregnancy), hyperemesis with electrolyte derangements, suspected PE/DVT requiring anticoagulation initiation, mono-mono twins from ~24 wk.

— Eclampsia with persistent neurologic deficit, pulmonary edema, ARDS (consider amniotic fluid embolism), septic shock, massive PPH with DIC, peripartum cardiomyopathy with hemodynamic compromise.

— Any pregnant patient ≥20 wk with trauma → minimum 4 hours of continuous monitoring (NST + tocodynamometry); extend to 24 hours if any contractions, bleeding, or non-reassuring tracing.

— Administer RhoGAM to Rh-negative patients after trauma; consider Kleihauer-Betke for large fetomaternal hemorrhage.

CCS pearl: A pregnant patient at 32 weeks with BP 168/112, headache, and 3+ proteinuria — on the CCS: IV access, IV labetalol or hydralazine for acute BP control, IV magnesium sulfate 4–6 g load then 2 g/hr, betamethasone for fetal lung maturity, admit to L&D, MFM consult, plan delivery once stabilized; do not wait for "more data."

Board pearl: Pyelonephritis in pregnancy is always admitted for IV antibiotics (ceftriaxone) due to high rate of preterm labor and sepsis; outpatient PO therapy is not standard, unlike in non-pregnant adults.

MFM consultation indications:

Genetics referral:

Same-day evaluation in L&D triage:

Inpatient admission criteria:

ICU transfer:

Trauma in pregnancy:

Differentials — Within Obstetric Categories

— T1: implantation, threatened/inevitable/incomplete/complete/missed abortion, ectopic, molar, cervical/vaginal pathology.

— T2: late miscarriage, cervical insufficiency, abruption, previa, infection.

— T3: bloody show (normal), placenta previa (painless), abruption (painful), vasa previa (rupture of membranes + bleeding + fetal bradycardia), uterine rupture (prior cesarean, sudden pain, loss of station).

— Obstetric: labor, abruption, uterine rupture, HELLP (RUQ), chorioamnionitis, round ligament pain (T2), Braxton-Hicks.

— Differentiate from non-obstetric (next chunk).

— Chronic HTN: BP ≥140/90 before 20 wk or pre-pregnancy.

— Gestational HTN: BP ≥140/90 after 20 wk, no proteinuria, no severe features.

— Preeclampsia: gestational HTN + proteinuria or end-organ dysfunction.

— Preeclampsia with severe features: BP ≥160/110, thrombocytopenia <100k, transaminitis 2× ULN, Cr >1.1, pulmonary edema, headache/visual symptoms.

— Eclampsia: seizures.

— HELLP: Hemolysis, Elevated LFTs, Low Platelets.

— Chronic HTN with superimposed preeclampsia.

— PUPPP (3rd trimester, abdominal striae, sparing periumbilical area, benign).

— Intrahepatic cholestasis (palms/soles, worse at night, elevated bile acids, risk of stillbirth).

— Pemphigoid gestationis (autoimmune, periumbilical bullae).

— Atopic eruption of pregnancy.

Key distinction: Cholestasis = palms/soles itching, normal skin, elevated bile acids → fetal risk and deliver by 36–37 wk if bile acids ≥100. PUPPP = striae-based rash → benign, topical steroids and antihistamines, term delivery.

Board pearl: Painless bright-red bleeding in T3 = previa until proven otherwise — order transabdominal/transvaginal US before any digital exam.

Vaginal bleeding by trimester (must differentiate):

Abdominal pain in pregnancy:

Hypertension in pregnancy spectrum:

Pruritus in pregnancy:

Differentials — Non-Obstetric Mimics in Pregnancy

— Beyond normal NVP and hyperemesis: thyrotoxicosis, gastroenteritis, pyelonephritis, hepatitis, pancreatitis, appendicitis, DKA, molar pregnancy, preeclampsia with hepatic involvement.

— HELLP/preeclampsia hepatic capsule distention, acute fatty liver of pregnancy, cholecystitis (more common in pregnancy), hepatitis, appendicitis (appendix displaces upward in T3, can mimic RUQ pain), pneumonia.

— Physiologic dyspnea of pregnancy (gradual, exertional only).

— Pathologic: PE, asthma exacerbation, peripartum cardiomyopathy, pulmonary edema (preeclampsia, tocolytic-induced), pneumonia, anemia.

— Tension, migraine, preeclampsia/eclampsia, cerebral venous thrombosis (pregnancy is hypercoagulable), PRES, pituitary apoplexy, subarachnoid hemorrhage.

— Physiologic edema vs DVT (asymmetric, more often left-sided in pregnancy due to iliac vein compression).

— Physiologic frequency vs cystitis vs pyelonephritis (admit) vs nephrolithiasis (US first-line imaging).

— Iron deficiency (most common) vs physiologic dilutional vs B12/folate deficiency vs hemoglobinopathy vs hemolysis (HELLP, AIHA).

— Normal pregnancy ↑ TBG → ↑ total T4 with normal free T4; trust free T4 and TSH, not total T4.

— hCG cross-stimulation of TSH receptor in T1 can cause transient gestational thyrotoxicosis (especially with hyperemesis) — distinguished from Graves by absence of TRAb/ophthalmopathy; usually self-resolves.

Key distinction: Acute fatty liver of pregnancy (AFLP) vs HELLP — both T3, both with elevated LFTs; AFLP has hypoglycemia, profound coagulopathy, and renal failure, often with LFTs higher and platelets relatively preserved early. Both → deliver promptly.

Board pearl: Imaging is not contraindicated in pregnancy when clinically indicated — CT, V/Q, MRI without gadolinium are all acceptable; withholding indicated imaging causes more harm than fetal radiation exposure below 50 mGy.

Nausea/vomiting:

Right upper quadrant pain:

Dyspnea:

Headache:

Lower-extremity swelling/pain:

Urinary symptoms:

Anemia:

Thyroid mimics:

Postpartum Planning and Long-Term Health Trajectory

— Initial contact within 3 weeks, comprehensive visit by 12 weeks postpartum — not a single 6-week visit.

— Topics: mood (PHQ-9 / EPDS), infant feeding, contraception, sleep, pain, sexual health, chronic disease transition, future pregnancy planning.

— LARC (IUD, implant) safe immediately postpartum, including breastfeeding.

— Progestin-only methods (POP, DMPA, implant) safe in breastfeeding.

— Combined estrogen-progestin — avoid until 6 weeks postpartum (VTE risk), longer if other risk factors; generally avoided in breastfeeding mothers until milk supply established (~6 weeks).

— Permanent: postpartum tubal ligation or vasectomy.

— GDM: 75-g 2-hour OGTT at 4–12 weeks postpartum, then screen every 1–3 years; 50% lifetime risk of T2DM.

— Gestational HTN/preeclampsia: BP check at 7–10 days and 6 weeks; lifetime cardiovascular risk doubled — counsel on long-term ASCVD risk modification.

— Postpartum thyroiditis: screen if symptomatic; up to 50% develop permanent hypothyroidism.

— Exclusive breastfeeding 6 months, continue with complementary foods to 12 months+.

— Contraindications: HIV (in US), active untreated TB, HSV lesion on breast, certain medications (chemo, radioactive isotopes), maternal substance use.

Step 3 management: A patient with GDM A2 at her 6-week postpartum visit — order 75-g 2-hour OGTT now, not A1c (less sensitive immediately postpartum); counsel on weight loss, breastfeeding (protective), and annual T2DM screening.

Board pearl: Preeclampsia is a cardiovascular risk equivalent for life — these patients warrant lifelong BP surveillance, lipid screening, and lifestyle counseling.

Postpartum care visits (ACOG "fourth trimester"):

Contraception counseling before discharge:

Disease-specific postpartum follow-up:

Breastfeeding:

Vaccines deferred during pregnancy given postpartum: MMR, varicella, HPV (if eligible).

Postpartum depression: screen at every postpartum visit; PHQ-9 or EPDS; treat with SSRI (sertraline preferred in lactation) + therapy; postpartum psychosis is a psychiatric emergency.

Follow-Up, Monitoring, and Health-Maintenance Integration

— BP, weight, urine dipstick (protein, glucose), fundal height (from 20 wk), FHTs, fetal movement inquiry, contractions/bleeding/leakage of fluid, mood screen, IPV screen each trimester, medication review.

— T1: dating US, initial labs, cfDNA/first-tri screen, NT 11–13+6 wk, aspirin start by 16 wk if indicated.

— T2: quad screen 15–20 wk, anatomy US 18–22 wk, cervical length if prior PTB.

— T3 (24–28): GLT, repeat CBC, RhoGAM 28 wk, Tdap 27–36 wk, RSV 32–36 wk in season.

— T3 (35–37): GBS swab, repeat HIV/STI if high-risk, growth scan if indicated.

— T3 (≥36): weekly visits, presentation check, plan for delivery.

— NST weekly or twice weekly, BPP if NST nonreactive; AFI or MVP for amniotic fluid; umbilical artery Dopplers for IUGR.

— T1: pregnancy options, lifestyle, genetic screening, immunizations.

— T2: prenatal classes, anatomy results, feeding plan.

— T3: labor signs, anesthesia options, GBS, postpartum/contraception, breastfeeding, infant care, car seat, depression awareness.

— Transfer of prenatal record to delivering hospital by ~36 weeks if separate from clinic; ensures GBS, antibody, and risk-status info available intrapartum.

— Confirm insurance coverage, WIC enrollment if eligible, lactation support availability, mental health resources, dental care during pregnancy (Medicaid-covered in most states).

CCS pearl: Every prenatal CCS case rewards the disciplined sequence — vitals, urine dip, fundal height, FHTs, ask about movement/contractions/bleeding — before deciding on labs or imaging. Advance the clock to the next gestational milestone and re-order accordingly.

Board pearl: Missing the 36-week record transfer to L&D is a classic transitions-of-care failure that surfaces on Step 3 patient-safety questions.

Routine prenatal visit checklist (each visit):

Trimester-anchored milestones (quick recall):

Antenatal surveillance in high-risk:

Counseling cadence:

Documentation & continuity:

Health-system integration:

Ethical, Legal, and Patient Safety Considerations

— Aneuploidy screening must be offered to all patients; consent should include sensitivity, specificity, false-positive rates (especially cfDNA in low-prevalence populations), and that diagnostic confirmation (CVS/amnio) is required before irreversible decisions.

— Patients may decline any screen — document shared decision-making.

— A competent pregnant patient may refuse any intervention, including cesarean delivery, transfusion, or recommended treatment — ACOG strongly opposes court-ordered interventions. Document discussion of risks, benefits, alternatives.

— Minors may consent to prenatal care, STI testing, and contraception in most states; document confidential conversation. Mandatory reporting applies for suspected statutory rape in many states — know local law.

— Routine, private screening every trimester; provide safety planning, resources, and shelter referral. Pregnancy increases IPV severity and homicide risk. Reporting to law enforcement is generally not mandatory without patient consent except for injuries from weapons in many states.

— Counsel on confidentiality limits — some states mandate reporting of prenatal substance use to child protective services. Punitive policies reduce care-seeking; emphasize harm reduction and treatment.

— Document refusal of indicated vaccines (Tdap, flu, RSV); revisit at subsequent visits.

— Record transfer to delivering facility by 36 weeks; flag GBS status, antibody screen, allergies, prior cesarean type, MFM consults.

— Medication reconciliation at each visit — particularly for antihypertensives, antiepileptics, antidepressants where doses change.

— Black, Indigenous, and rural patients face 3–4× higher maternal mortality; structured risk assessment and bias mitigation are patient-safety imperatives.

Step 3 management: A 28-year-old Jehovah's Witness refuses blood products and is at high risk for PPH due to placenta previa — respect autonomy, document an advance directive specifying acceptable products (e.g., albumin, cell saver) before delivery, optimize hemoglobin antepartum with iron and erythropoietin, plan delivery at a tertiary center with bloodless-medicine protocols, and ensure clear intrapartum communication with the entire team.

Board pearl: Court-ordered cesareans are not standard of care in the US — ACOG opposes them; respecting refusal with thorough documentation is the right answer.

Informed consent for screening vs diagnostic testing:

Maternal autonomy:

Confidentiality and adolescents:

Intimate partner violence:

Substance use disclosure:

Vaccine refusal:

Patient safety in transitions:

Maternal mortality disparities:

High-Yield Associations and Rapid-Fire Clinical Facts

— T21: ↓AFP, ↑hCG, ↓estriol, ↑inhibin A.

— T18: ↓all four (AFP, hCG, estriol; inhibin A normal/low).

— Open NTD: ↑AFP, normal others.

Board pearl: "Pregnancy + new severe headache + BP elevation + visual changes" = preeclampsia until proven otherwise — magnesium and BP control before workup completes.

First-trimester ultrasound CRL = most accurate dating method.

β-hCG should double every ~48 hours in early viable IUP; plateau or slow rise → ectopic or nonviable.

Discriminatory zone: β-hCG >3,500 mIU/mL without intrauterine gestation on TVUS → suspect ectopic.

NT ≥3 mm at 11–13+6 wk → ↑ aneuploidy and cardiac anomaly risk → fetal echo.

Quad screen patterns:

Anti-D RhoGAM events: delivery, abortion, ectopic, CVS/amnio, ECV, abdominal trauma, antepartum bleeding, routine 28-week dose.

GBS prophylaxis indications: positive 35–37 wk swab; GBS bacteriuria any time this pregnancy; prior infant with GBS disease; unknown status with <37 wk labor, ROM ≥18 hr, intrapartum fever ≥100.4°F.

Aspirin for preeclampsia: start 12–28 wk, continue to delivery.

Tdap every pregnancy at 27–36 wk regardless of prior dosing.

RSV maternal vaccine (Abrysvo): 32–36 wk between Sept–Jan.

Influenza vaccine: any trimester; inactivated only.

Folic acid 4 mg if prior NTD, DM, antiepileptics.

CHAP trial: treat chronic HTN to <140/90.

Listeria → avoid soft cheeses, deli meats.

Vitamin A teratogen in excess (>10,000 IU); isotretinoin contraindicated.

GDM screen window 24–28 wk (early if BMI ≥30, prior GDM, PCOS, prior macrosomia).

Cervical length <25 mm + prior PTB → vaginal progesterone ± cerclage.

Postpartum thyroiditis classically 1–6 months postpartum — hyperthyroid → hypothyroid → euthyroid (or permanent hypo).

Sertraline = preferred SSRI in pregnancy/lactation; paroxetine avoided (cardiac defects).

Universal HCV screening in every pregnancy.

Board Question Stem Patterns

Step 3 management: Recurring stem theme — when the next visit milestone is in the question (28 wk, 36 wk), match to RhoGAM/Tdap, GBS swab respectively. Step 3 rewards knowing what to do at this visit and what to schedule for the next.

Board pearl: If a stem mentions chronic HTN, prior preeclampsia, DM, renal disease, autoimmune, or multiples — the answer almost always includes low-dose aspirin somewhere.

"28-year-old G1 at 9 weeks for first prenatal visit" — answer: dating ultrasound + initial prenatal labs including HCV, offer aneuploidy screening, start prenatal vitamin with folate.

"G2P1 with prior preeclampsia at 12 weeks" — answer: start low-dose aspirin 81 mg, schedule serial BPs and growth scans.

"Rh-negative G1 at 28 weeks, antibody screen negative" — answer: administer anti-D immunoglobulin (RhoGAM) 300 mcg IM today.

"G2P1 at 26 weeks, 1-hr GLT 162 mg/dL" — next step: 3-hour 100-g OGTT; two abnormal values → GDM.

"G1 at 36 weeks, vaginal-rectal swab positive for GBS" — at labor onset: IV penicillin G (cefazolin if non-anaphylactic PCN allergy; vancomycin or clindamycin if confirmed susceptibility for severe allergy).

"G2P1 at 32 weeks with BP 168/110, headache, proteinuria 4+" — IV labetalol, IV magnesium sulfate, admit, betamethasone, plan delivery (severe features → deliver ≥34 wk; <34 expectant only if stable in tertiary care).

"G1 on lisinopril for chronic HTN, now 7 weeks pregnant" — discontinue lisinopril, start labetalol; target <140/90.

"Patient with prior NTD-affected pregnancy planning conception" — folic acid 4 mg/day preconception.

"G1 at 11 weeks with NT 3.5 mm" — counsel ↑ aneuploidy + cardiac anomaly risk; offer diagnostic testing (CVS now or amnio later), plan fetal echo at 20–22 wk.

"15-year-old at 8 weeks unaccompanied" — provide confidential prenatal care, screen IPV/coercion, social work; do not require parental consent.

"G3P2 at 38 wk with painless bright-red bleeding, prior cesarean × 2" — ultrasound first (rule out previa/accreta); no digital exam.

"G1 at 6 weeks with hyperthyroidism on methimazole" — switch to PTU for first trimester.

"Pregnant patient with leg swelling and pleuritic chest pain" — do not withhold imaging; CTPA or V/Q; start LMWH.

One-Line Recap

Routine prenatal care is a structured, milestone-anchored program of risk assessment, screening, counseling, and immunization across pregnancy — confirm dating in the first trimester, stratify risk at the initial visit, follow ACOG visit cadence (q4 wk → q2 wk → q1 wk), screen aneuploidy/anatomy/GDM/GBS at defined windows, and integrate preeclampsia prevention, vaccines, and postpartum planning throughout.

Board pearl: On Step 3, the highest-yield prenatal care questions test what to order at this gestational age and what to schedule next — memorize the visit-by-visit milestone grid and the aspirin/RhoGAM/Tdap/RSV/GBS sequence cold.

Dating + initial labs + risk stratification drive every downstream decision; first-trimester CRL anchors EDD, and the initial visit identifies aspirin candidates, MFM referrals, and teratogen switches.

Milestone screens: cfDNA/first-tri screen 10–13+6 wk → anatomy 18–22 wk → GLT 24–28 wk → RhoGAM 28 wk → Tdap 27–36 wk → RSV 32–36 wk (in season) → GBS 35–37 wk.

Preeclampsia prevention with aspirin 81 mg from 12–28 wk if ≥1 high-risk or ≥2 moderate-risk factors; treat chronic HTN to <140/90 (CHAP).

Postpartum is care, not closure — contact within 3 weeks, comprehensive visit by 12 weeks, with disease-specific follow-up (OGTT after GDM, BP after preeclampsia), contraception, and depression screening; preeclampsia and GDM are lifelong cardiometabolic risk markers.