CCS Integrated Cases

CCS case: prenatal visit at 28 weeks gestation

Clinical Overview and When to Suspect Routine 28-Week Prenatal Care

— Gestational diabetes screening (50-g GCT) if not already completed at 24–28w

— CBC to reassess for physiologic anemia of pregnancy (hemoglobin nadir around 28–32w due to plasma volume expansion)

— Anti-D immunoglobulin (RhoGAM) 300 mcg IM in all Rh(D)-negative, antibody-negative patients

— Tdap vaccination between 27–36 weeks (every pregnancy, regardless of prior Tdap)

— Repeat antibody screen in Rh-negative patients before giving RhoGAM

— Fetal movement counseling ("kick counts" beginning ~28w)

CCS pearl: On the CCS interface, the 28-week visit is an office setting case. Move the clock in increments (advance to "results available"), and remember that orders like RhoGAM and Tdap should be entered at this visit, not deferred — the case clock penalizes missed time-sensitive prophylaxis. Always re-check vitals and update the problem list before closing the encounter.

The 28-week visit is a pivotal third-trimester milestone that bundles screening, immunization, alloimmunization prophylaxis, and anticipatory guidance for the remainder of pregnancy

Standard ACOG visit cadence shifts at 28 weeks: from every 4 weeks (up to 28w) → every 2 weeks (28–36w) → weekly (36w–delivery)

Core deliverables at this visit:

Risk reassessment: re-screen for preeclampsia symptoms, preterm labor signs, depression (Edinburgh or PHQ-9), and intimate partner violence

Confirm fundal height (should approximate gestational age in cm ±2), fetal heart tones, BP, weight, urine dip for protein/glucose

Verify prenatal labs from earlier trimesters are complete: blood type/Rh, antibody screen, CBC, HIV, RPR, HBsAg, rubella, varicella, urine culture, Pap (if due), STI panel; many programs repeat HIV and syphilis in the third trimester (universal third-trimester syphilis rescreening is now CDC/USPSTF-endorsed)

Presentation Patterns and Key History

— Vaginal bleeding (placenta previa, abruption, preterm labor)

— Leakage of fluid (PPROM)

— Regular contractions or pelvic pressure (preterm labor — concerning if ≥6/hour)

— Decreased fetal movement (counsel: ≥10 movements in 2 hours once daily)

— Severe/persistent headache, scotomata, RUQ pain, swelling (preeclampsia with severe features)

— Dysuria, flank pain (asymptomatic bacteriuria → pyelonephritis risk)

— Pruritus, especially palms/soles (cholestasis of pregnancy, usually later but possible)

— Tobacco, alcohol, cannabis, opioid use (re-screen each trimester; 4 P's or NIDA Quick Screen)

— Domestic violence (peaks during pregnancy)

— Depression and anxiety (perinatal mood disorders)

— Seatbelt use, work exposures, travel plans (Zika-endemic areas)

— Plans for breastfeeding, contraception postpartum, pediatrician selection

— Prior preterm birth → discuss progesterone if not already initiated and cervical length surveillance

— Prior preeclampsia, GDM, stillbirth, or shoulder dystocia → tailored surveillance

— Prior cesarean → confirm delivery plan (TOLAC vs repeat CD by ~36w)

Step 3 management: A patient at 28 weeks reporting 6+ contractions per hour, pelvic pressure, or any vaginal bleeding/fluid must be redirected from the office to labor and delivery for evaluation — do not perform a digital cervical exam in the office until placenta previa is excluded by prior ultrasound.

Board pearl: Decreased fetal movement is the single most common chief complaint that should trigger immediate NST in the third trimester, even if the rest of the exam is normal.

The 28-week visit is typically asymptomatic and routine, but the history must actively screen for third-trimester red flags rather than rely on the patient to volunteer them

Targeted ROS at every third-trimester visit:

Social/behavioral history to revisit:

Obstetric history pertinent to risk:

Physical Exam Findings and Maternal-Fetal Assessment

— BP <140/90 reassuring; ≥140/90 on two occasions ≥4h apart = gestational HTN/preeclampsia workup

— Sudden weight gain (>2 lb/week) may signal preeclampsia-related edema

— Maternal HR typically 10–20 bpm above baseline; afebrile

— Measure from pubic symphysis to top of fundus in cm; should equal gestational age ±2 cm between 20–36 weeks

— Lag >3 cm → ultrasound for IUGR, oligohydramnios, malpresentation

— Excess >3 cm → ultrasound for macrosomia, polyhydramnios, multiples, fibroids, undiagnosed GDM

Key distinction: Physiologic dyspnea of pregnancy (gradual, exertional, no orthopnea, normal SpO₂) vs pathologic dyspnea (sudden, orthopnea, chest pain, hypoxia — consider PE, peripartum cardiomyopathy, pulmonary edema of preeclampsia). Pregnancy is a hypercoagulable state and PE remains a leading cause of maternal mortality.

CCS pearl: Always enter "vital signs" and "fetal heart tones" as orders at the start of every prenatal visit on CCS — the interface treats these as discrete actions and abnormal results will not appear unless ordered. Then advance the clock to review results before deciding on screening labs.

Vital signs — every visit; the most important data point

Fundal height (McDonald's measurement)

Fetal heart tones by handheld Doppler: normal 110–160 bpm

Leopold maneuvers become more informative after 32–34w; at 28w fetus often still mobile

Edema: dependent edema is physiologic; facial or hand edema with hypertension is concerning

DTRs check only if preeclampsia suspected (hyperreflexia, clonus)

Pelvic exam: not routine at 28w unless symptoms; defer until 36w GBS swab or earlier if bleeding/leakage (sterile speculum, not digital, if PPROM suspected)

Urine dipstick in office: trace protein common; ≥1+ proteinuria with HTN → send protein/creatinine ratio (≥0.3 diagnostic)

Diagnostic Workup — Standard 28-Week Labs and Screening

— 1-hour 50-g oral glucose challenge test (GCT) for gestational diabetes screening

— CBC (screen for anemia; physiologic nadir at this gestational age)

— Antibody screen (indirect Coombs) in Rh(D)-negative patients before administering anti-D Ig

— RPR or treponemal test (third-trimester rescreen — CDC now recommends universal rescreen at 28w)

— HIV rescreen in high-prevalence jurisdictions or high-risk patients

— Urinalysis ± culture if symptoms or history of bacteriuria

— Non-fasting; 50 g glucose load; plasma glucose at 1 hour

— ≥140 mg/dL (some institutions 130) → proceed to diagnostic 3-hour 100-g OGTT

— ≥200 mg/dL → presumptive GDM, may skip OGTT in some protocols

— Hgb <11 in 1st/3rd trimester or <10.5 in 2nd = anemia; check iron studies (low ferritin → oral iron 325 mg ferrous sulfate TID or every-other-day dosing for better absorption)

— MCV low → iron deficiency or thalassemia; MCV high → B12/folate

Board pearl: Even in patients who already received first-trimester RhoGAM (e.g., after bleeding), the routine 28-week dose is still indicated — the prophylactic window is ~12 weeks.

Step 3 management: Document Rh status, antibody screen result, and RhoGAM administration in the chart — missing this trio is a classic malpractice/safety vignette.

Order set at the 28-week visit (CCS):

GCT interpretation:

3-hour 100-g OGTT (Carpenter-Coustan): fasting, 1h, 2h, 3h thresholds 95/180/155/140 mg/dL — two or more abnormal values = GDM

CBC interpretation:

Antibody screen: if positive in Rh-negative patient with unknown antibody, identify and titer before giving RhoGAM; alloimmunization (anti-D titer ≥1:16) → MFM referral and MCA Doppler for fetal anemia

Diagnostic Workup — Targeted or Indication-Based Studies

— Size-dates discrepancy >3 cm

— Decreased fetal movement

— Vaginal bleeding (rule out previa/abruption)

— Suspected malpresentation late third trimester

— Known placenta previa (re-evaluate placental location)

— Diabetes, hypertension, prior IUGR → growth ultrasound every 3–4 weeks starting ~28w

Key distinction: A patient with GDM A1 (diet-controlled) typically does not need antenatal testing until 32–36w; a patient with GDM A2 (medication-controlled), pregestational diabetes, or hypertension warrants twice-weekly NST or weekly BPP starting at 32w (earlier if poorly controlled).

CCS pearl: On the case, ordering an ultrasound "just to look" without an indication wastes clock time and adds nothing — the grading favors indicated testing. If fundal height is normal and the patient is asymptomatic, skip imaging at 28w.

Ultrasound at 28 weeks is not routine in low-risk pregnancies (anatomy scan was done at 18–22w); order only for indications:

Antenatal testing (NST, BPP): initiated typically at 32 weeks for most high-risk conditions, but earlier (26–28w) for severe conditions (chronic HTN with superimposed disease, pregestational diabetes with vasculopathy, fetal growth restriction)

Cervical length by transvaginal ultrasound is part of preterm-birth surveillance in patients with prior spontaneous preterm birth (every 2 weeks from 16–24w) — by 28w this surveillance period has typically ended

GBS culture is NOT done at 28w — that occurs at 36 0/7 – 37 6/7 weeks

Repeat STI testing at 28w in patients with risk factors: chlamydia/gonorrhea NAAT, hepatitis C (universal screening now recommended each pregnancy)

TSH if symptomatic or known thyroid disease (not universal screen)

Lupus anticoagulant/anticardiolipin not routinely repeated; obtained earlier if APLS suspected

Risk Stratification and Visit Decision Logic

— Office vital signs entered → if BP ≥140/90 or symptomatic, this is no longer a routine visit; escalate workup for preeclampsia

— Fetal heart tones absent or <110/>160 → move to L&D for continuous monitoring

— Low risk: singleton, normotensive, no medical comorbidities, normal first/second-trimester labs → standard 28w order set

— Moderate risk: advanced maternal age, obesity, prior GDM, chronic well-controlled HTN → add growth ultrasounds, low-dose aspirin if not already on it, earlier antenatal testing planning

— High risk: pregestational diabetes, chronic HTN with end-organ disease, prior preterm birth <34w, prior stillbirth, MFM co-management

— Low-dose aspirin 81 mg daily should already be running since 12–16w in any patient with ≥1 high-risk factor (prior preeclampsia, chronic HTN, pregestational DM, renal disease, autoimmune disease, multifetal gestation) or ≥2 moderate-risk factors (nulliparity, obesity, age ≥35, family history, sociodemographic)

— If missed, start now — still has benefit when initiated up to 28w

— RhoGAM (Rh-negative)

— Tdap (every pregnancy 27–36w)

— GCT results pending or ordered

— Influenza vaccine in season; COVID-19 and RSV vaccine (32–36w, seasonal Sep–Jan) anticipated next visit

Step 3 management: A patient at 28w with chronic hypertension whose home BPs are creeping up (e.g., 138–142/88–92) but office BP is "normal" requires ambulatory BP confirmation, baseline preeclampsia labs (CBC, AST/ALT, creatinine, urine protein/creatinine), and increased visit frequency — do not wait for the next routine 4-week interval.

CCS pearl: Build your order set in this order — vitals → fetal heart tones → screening labs → vaccines/RhoGAM → counseling. Advance the clock and reassess.

Step 1 — Triage on arrival:

Step 2 — Identify the patient's risk tier:

Step 3 — Preeclampsia prevention review:

Step 4 — Confirm time-sensitive interventions at this visit:

Pharmacotherapy and Immunization Order Set

— Indication: Rh(D)-negative, antibody-negative patient at 28w

— Also given within 72 hours of any sensitizing event (bleeding, trauma, amniocentesis, version, delivery of Rh-positive infant)

— Document lot number; verify antibody screen negative before administration

— Every pregnancy, 27–36 weeks (optimal 27–32w to maximize neonatal antibody transfer)

— Protects neonate against pertussis until they receive their own DTaP at 2 months

— Safe regardless of interval from prior Tdap

Board pearl: Live vaccines are contraindicated in pregnancy — MMR, varicella, LAIV, smallpox, yellow fever (relative). Tdap, inactivated flu, COVID mRNA, RSV, and Hep B are all safe.

CCS pearl: Enter immunizations as discrete orders — "Tdap vaccine IM" and "Rh immune globulin 300 mcg IM" — the case credits the specific action, not generic "vaccinate."

RhoGAM (anti-D immune globulin) 300 mcg IM

Tdap vaccine 0.5 mL IM in deltoid

Influenza vaccine (inactivated) — any trimester during flu season; live attenuated (FluMist) contraindicated

COVID-19 vaccine/booster — recommended in pregnancy; mRNA preferred

RSV vaccine (Abrysvo, RSVpreF) — single dose at 32 0/7 – 36 6/7 weeks during September–January (seasonal); alternative is nirsevimab for the infant after birth — not both

Iron supplementation if anemic: ferrous sulfate 325 mg PO daily or every other day (better absorption, less GI upset); take with vitamin C, separate from calcium

Aspirin 81 mg daily continue through 36 weeks (some continue to delivery) for preeclampsia prophylaxis

Prenatal vitamin with folic acid 400–800 mcg and iron — continue daily

Calcium/Vitamin D as needed for dietary inadequacy

17-OH progesterone caproate — no longer recommended (withdrawn from market 2023); vaginal progesterone still used for short cervix

Counseling, Anticipatory Guidance, and Procedural Considerations

— Method: lie on left side once daily, count distinct movements; ≥10 movements in 2 hours is reassuring

— Decreased movement → present to L&D for NST

— Air travel generally safe through 36 weeks (singletons) / 32 weeks (multiples); most airlines restrict after 36w

— DVT prevention: hydration, ambulation every 1–2h, compression stockings

— Avoid Zika-endemic regions

Step 3 management: A patient who screens positive on the EPDS (≥10) at 28w should receive a same-visit safety assessment, behavioral health referral, and consideration of SSRI initiation (sertraline first-line in pregnancy); document the plan and follow up within 2 weeks.

CCS pearl: "Counsel patient" orders do count on the CCS interface — enter "counseling, fetal kick counts," "counseling, preterm labor signs," and "counseling, preeclampsia warning signs."

Fetal movement (kick) counts starting at 28 weeks

Preterm labor warning signs: ≥6 contractions/hour, pelvic pressure, low back pain, vaginal bleeding, fluid leakage → present immediately

Preeclampsia warning signs: severe headache unrelieved by acetaminophen, visual changes, RUQ pain, rapid swelling of face/hands, shortness of breath

Travel counseling:

Exercise: 150 min/week moderate activity continues to be safe; avoid contact sports, scuba diving, supine exercises after 20w

Sexual activity: safe unless placenta previa, PPROM, or preterm labor risk

Nutrition: total pregnancy weight gain depends on pre-pregnancy BMI (IOM: normal BMI 25–35 lb total); avoid raw fish, deli meats unheated, unpasteurized dairy, high-mercury fish

Breastfeeding counseling — discuss benefits, plan for first hour, lactation resources

Labor planning: preferences, doula, support persons, hospital tour, prenatal classes

Postpartum contraception discussion begins now — LARC at delivery, progestin-only options compatible with breastfeeding

Depression and IPV screening — repeat at this visit

Special Populations — Advanced Maternal Age and Medical Comorbidities

— Increased risk: aneuploidy (addressed by first/second-trimester screening), GDM, hypertensive disorders, stillbirth, cesarean delivery

— At 28w: confirm low-dose aspirin is on board; counsel on antenatal testing starting 36w (weekly NST) and delivery by 39–40w to reduce stillbirth risk

— Higher risk: GDM, preeclampsia, OSA, VTE, fetal anomalies, shoulder dystocia

— GCT screening at 28w is essential; consider earlier screen at first prenatal if BMI ≥40 or prior GDM

— VTE prophylaxis assessment for hospitalization or cesarean

— Goal BP <140/90 in pregnancy (CHAP trial — treating mild chronic HTN improves outcomes without increasing SGA)

— Preferred agents: labetalol, nifedipine ER, methyldopa; ACE-I/ARBs contraindicated (fetal renal damage, oligohydramnios)

— Aspirin 81 mg, baseline preeclampsia labs at this visit, serial growth ultrasounds

— Target fasting <95, 1h postprandial <140, 2h <120

— A1c goal <6% if achievable without hypoglycemia

— Insulin is first-line; metformin/glyburide are alternatives but cross placenta

— Anatomy scan + fetal echo at 22–24w; growth ultrasounds q4w from 28w; antenatal testing from 32w (earlier if vasculopathy)

— Higher risk of preeclampsia, IUGR, preterm birth; MFM co-management

Key distinction: Gestational HTN (new HTN ≥20w, no proteinuria/severe features) vs preeclampsia (HTN + proteinuria or severe features/end-organ damage) vs chronic HTN with superimposed preeclampsia (preexisting HTN + new proteinuria or worsening BP/end-organ findings). Management diverges sharply — superimposed preeclampsia frequently triggers delivery planning by 34–37w.

Advanced maternal age (≥35 at delivery)

Obesity (BMI ≥30)

Chronic hypertension

Pregestational diabetes (T1/T2)

Renal disease (CKD)

Asthma, thyroid disease, epilepsy, lupus — ensure controller therapy continues, levels checked

Special Populations — Multifetal Gestation, Prior Preterm Birth, and Substance Use

— Higher risk: preterm birth, preeclampsia, GDM, IUGR, anemia, postpartum hemorrhage

— At 28w: growth ultrasound every 4w (dichorionic) or every 2w (monochorionic) for discordance/TTTS surveillance

— Iron requirement higher; check CBC

— Delivery planning: dichorionic-diamniotic 38w, monochorionic-diamniotic 36–37w, monochorionic-monoamniotic 32–34w cesarean

— Aspirin 81 mg for preeclampsia prophylaxis (multifetal = high-risk indication)

— Vaginal progesterone (200 mg suppository nightly) from 16–36w if singleton with short cervix; ongoing at 28w

— Cervical length surveillance ended by 24w; if cerclage placed, remove at 36–37w

— Counsel on preterm labor signs intensively

— Brief intervention (5 A's), nicotine replacement therapy can be considered after risk-benefit discussion; varenicline/bupropion data limited

— Methadone or buprenorphine (not detox) is standard of care; co-manage with addiction medicine

— Naloxone access; screen for hepatitis C, HIV

— Plan for neonatal abstinence syndrome (NAS) assessment at delivery; notify pediatrics/social work

Board pearl: Buprenorphine and methadone in pregnancy are standard of care — opioid detox is associated with relapse and increased fetal/maternal mortality and is not recommended.

Step 3 management: A 28-week patient on buprenorphine should have dose increases as pregnancy progresses (increased volume of distribution, metabolism); coordinate with addiction medicine, plan for delivery hospital with NAS protocol, and connect to early-intervention services postpartum.

Multifetal gestation (twins, triplets)

Prior spontaneous preterm birth <37w

Tobacco use

Alcohol use — abstinence is the only safe message; FAS risk

Opioid use disorder

Cannabis — counsel against use; data suggest IUGR, neurodevelopmental concerns

Complications and Adverse Outcomes Detected at the 28-Week Visit

— Start dietary counseling, glucose self-monitoring (fasting + 1h postprandial QID)

— Diet/exercise first; if targets not met in 1–2 weeks → insulin (preferred) or metformin/glyburide (second-line; both cross placenta but commonly used)

— Growth ultrasounds q3–4w; antenatal testing from 32w if A2 or poorly controlled

— Severe features (BP ≥160/110, platelets <100k, AST/ALT 2× normal, Cr >1.1, pulmonary edema, neurologic symptoms) → deliver regardless of gestational age once stabilized (after antenatal corticosteroids if <34w)

— Preeclampsia without severe features at 28w → inpatient or close outpatient surveillance, expectant management to 37w

— Tocolysis (nifedipine or indomethacin <32w) for 48h to enable corticosteroids

— Betamethasone 12 mg IM q24h × 2 doses for fetal lung maturity (24–34w; consider 34–36+6w late preterm)

— Magnesium sulfate for neuroprotection if <32w

— GBS prophylaxis with penicillin if delivery anticipated

CCS pearl: When a complication is uncovered at a routine visit, change the setting on the CCS interface from "office" to "labor and delivery" or "hospital ward" — orders and monitoring intervals differ, and the case will not credit inpatient-level care performed in the office setting.

Newly diagnosed gestational diabetes (positive GCT → positive OGTT)

New hypertension or preeclampsia

Iron deficiency anemia — oral iron; IV iron (ferric carboxymaltose) if intolerant or severe

Asymptomatic bacteriuria/UTI — treat with nitrofurantoin (avoid near term and in G6PD), cephalexin, fosfomycin; avoid TMP-SMX in 1st and 3rd trimesters

Preterm labor (24w–34w)

PPROM — admit, latency antibiotics (ampicillin + azithromycin × 7d), corticosteroids, expectant to 34w

Decreased fetal movement → NST ± BPP; deliver if non-reassuring

Escalation, Consultation, and Disposition Decisions

— BP ≥160/110 confirmed on recheck

— Any severe-feature preeclampsia symptom (headache, scotomata, RUQ pain, dyspnea)

— Vaginal bleeding (any volume)

— Suspected PPROM (pooling, ferning, positive AmniSure/ROM Plus)

— Regular contractions ≥6/hour or cervical change

— Decreased fetal movement not improved with stimulation

— Non-reassuring fetal heart tones in office

— Continuous external fetal monitoring + tocodynamometry

— IV access (18g), normal saline or LR at maintenance

— CBC, CMP, urine protein/creatinine, urinalysis, type and screen

— Magnesium sulfate (preeclampsia with severe features, seizure prophylaxis) — 4–6 g IV load, then 1–2 g/hr

— Antihypertensives (IV labetalol 20 mg → 40 → 80, or IV hydralazine 5–10 mg, or PO immediate-release nifedipine 10 mg) for sustained BP ≥160/110

— Betamethasone if <34w and delivery possible within 7 days

— Twin gestation with complication, pregestational diabetes with vasculopathy, severe preeclampsia, fetal anomalies, alloimmunization, prior poor obstetric outcome

Step 3 management: A patient with BP 162/108 at the 28-week visit who is otherwise asymptomatic must be sent directly to L&D (not home with follow-up) — confirm BP, initiate workup, treat sustained severe-range BP within 30–60 minutes with IV labetalol or hydralazine to prevent maternal stroke.

CCS pearl: The case clock penalizes delayed treatment of severe-range BP — order antihypertensive immediately upon confirmation, do not wait for full lab workup.

From office to labor and delivery — escalate immediately if:

L&D initial orders (CCS):

MFM consultation:

Anesthesia consultation for patients with high BMI, prior spine surgery, cardiac disease, suspected difficult airway — ideally before delivery

NICU consultation if anticipated preterm delivery <34w

Social work for substance use, IPV, housing instability, lack of postpartum support

Key Differentials — Obstetric Causes of Third-Trimester Symptoms

— Placenta previa — painless bleeding, often after intercourse; confirmed by transabdominal/TV ultrasound; no digital exam

— Placental abruption — painful bleeding, tense/tender uterus, fetal distress, possibly concealed; clinical diagnosis (ultrasound poor sensitivity)

— Vasa previa — painless bleeding with rupture of membranes + sudden fetal bradycardia; cesarean at 34–36w if diagnosed prenatally

— Bloody show/preterm labor — small volume, mucus-mixed, with contractions

— Cervical/vaginal lesions — polyp, ectropion, cervicitis

— Preterm labor, abruption, HELLP syndrome (RUQ from hepatic capsule distension), acute fatty liver of pregnancy (rare, late), round ligament pain (benign, sharp, positional)

— Uterine rupture (prior cesarean, sudden pain, fetal distress, loss of station)

— Fetal sleep cycle (most common, transient), maternal sedation, anterior placenta dampening perception, fetal compromise (IUGR, hypoxia), fetal demise

— Physiologic dependent edema vs preeclampsia-associated (facial, sudden, with HTN) vs DVT (asymmetric, calf pain) vs cardiac (CHF, peripartum cardiomyopathy)

Key distinction: Abruption is a clinical diagnosis — a normal ultrasound does NOT rule it out. Painful bleeding with a tense uterus and fetal distress should be managed as abruption until proven otherwise, with immediate delivery if maternal/fetal status warrants.

Board pearl: Always ask about prior placenta location before performing any cervical/digital exam in a bleeding third-trimester patient — if previa is not excluded, perform sterile speculum only and proceed to ultrasound.

Third-trimester vaginal bleeding:

Third-trimester abdominal pain:

Decreased fetal movement:

Edema:

Key Differentials — Non-Obstetric Causes to Consider

— Essential chronic HTN (preexisting, ≥20w may mask), white-coat HTN, secondary causes (pheochromocytoma — rare but catastrophic; renal artery stenosis; primary aldosteronism; thyroid disease)

— Migraine (common, often improves in pregnancy), tension, preeclampsia, cerebral venous sinus thrombosis (hypercoagulable state), posterior reversible encephalopathy syndrome (PRES), pituitary apoplexy (rare; Sheehan-like), subarachnoid hemorrhage

— Physiologic vs pulmonary embolism (pregnancy = 5× baseline risk; D-dimer less useful; CT-PA or V/Q acceptable), peripartum cardiomyopathy (usually late third trimester to 5 months postpartum), pulmonary edema (preeclampsia, tocolytic-associated, valvular disease), asthma exacerbation, pneumonia

— Intrahepatic cholestasis of pregnancy — palms/soles, worse at night, elevated bile acids; risk of fetal demise; treat with ursodeoxycholic acid, deliver 36–37w (sooner if bile acids ≥100)

— PUPPP (pruritic urticarial papules — abdomen, sparing umbilicus, benign), pemphigoid gestationis (autoimmune, around umbilicus, vesicles)

— Appendicitis (RUQ displacement due to gravid uterus — atypical presentation), cholecystitis, pyelonephritis (right > left, fevers, CVA tenderness), nephrolithiasis

— Eclampsia until proven otherwise in third trimester; also stroke, epilepsy, hypoglycemia, infection, drug toxicity

Key distinction: A third-trimester seizure with hypertension is eclampsia — give magnesium sulfate 4–6 g IV load then 2 g/hr, control BP, and plan delivery. Do not pursue extensive neuroimaging before stabilizing and treating empirically.

Hypertension in pregnancy — broaden the differential:

Headache:

Dyspnea:

Pruritus:

Abdominal pain (non-OB):

Seizure:

Secondary Prevention and Long-Term Pregnancy Plan

— 28–36w: visits every 2 weeks

— 36w–delivery: weekly visits

— 36 0/7 – 37 6/7w: GBS rectovaginal culture

— 27–36w: Tdap (this visit), 32–36w: RSV vaccine (seasonal), 39–40w: delivery for most low-risk patients

— Continue aspirin 81 mg daily through 36w (some to delivery)

— Continue antihypertensives, target <140/90 (CHAP)

— Adequate calcium intake (1000 mg/day) in low-intake populations

— Postpartum follow-up: 75-g 2-hour OGTT at 4–12 weeks postpartum (not earlier — affected by recent pregnancy)

— Lifetime risk of T2DM ~50% — annual diabetes screening, lifestyle counseling, breastfeeding (reduces T2DM risk)

— RSV at 32–36w if not contraindicated

— COVID-19 booster as eligible

— Postpartum: catch-up MMR, varicella, HPV (through age 26) if not given pre-pregnancy

— LARC at delivery, progestin-only methods compatible with breastfeeding (POP, DMPA, implant, IUD); avoid combined estrogen for ≥21 days postpartum (VTE), ≥30 days if breastfeeding and additional risk factors

Step 3 management: Women with GDM, preeclampsia, or preterm birth have lifelong elevated cardiovascular risk — document these as "adverse pregnancy outcomes" in the chart; primary care should screen annually for hypertension, dyslipidemia, and diabetes. This is now formalized in AHA/ACC cardiovascular risk guidelines.

Beyond the 28-week visit — anticipatory plan:

Preeclampsia prevention bundle to maintain:

GDM management plan (if diagnosed):

Vaccinations to schedule:

Postpartum contraception plan started now:

Mental health plan: identify perinatal mood disorders early; postpartum depression screening at 1–6 weeks postpartum (PHQ-9 or EPDS)

Follow-Up, Monitoring Parameters, and Outpatient Handoff

— Routine: return in 2 weeks (30w visit)

— GDM diagnosis: see RD/CDE within 1 week, OB follow-up in 1–2 weeks for glucose log review

— New hypertension: home BP monitoring twice daily, return in 3–7 days, lower threshold for triage

— Anemia: recheck CBC in 4 weeks after starting iron

— BP, weight, urine dip, fundal height, fetal heart tones, fetal movement assessment, depression rescreen

— Confirm fetal position (Leopold), discuss labor preferences, review GCT/CBC, antenatal testing if indicated

— GBS culture, confirm presentation (external cephalic version if breech 36–37w), final labor plan, RSV vaccine if in season and not received

— Daily fetal kick counts after 28w

— Home BP cuff for any hypertensive patient — log AM/PM, bring to visits

— Glucose log QID for GDM

— Preterm labor warning signs

— Preeclampsia warning signs

— Decreased fetal movement instructions

— When to call vs when to go to L&D

CCS pearl: Always close the office visit with "schedule follow-up in 2 weeks" and explicit return precautions; entering "patient education" orders for warning signs is credited on the interface.

Next visit cadence after 28w:

Standard 30-week visit will include:

Standard 32–34w visit:

36-week visit:

Home monitoring instructions:

Patient education handouts to provide today:

Handoff to delivery hospital: prenatal records uploaded by 36w; pediatrician selected; lactation consult arranged

Postpartum visit: comprehensive postpartum visit by 12 weeks (ACOG "fourth trimester" model), with earlier touchpoint within 3 weeks — particularly important for hypertensive disorders (BP check 3–10 days postpartum), GDM, mood disorders

Ethical, Legal, and Patient Safety Considerations

— Patients may decline RhoGAM, Tdap, or GCT — document the discussion of risks (Rh alloimmunization in future pregnancies, neonatal pertussis, undiagnosed GDM), the patient's understanding, and the decision

— Provide written information; revisit at subsequent visits — declining once does not preclude future acceptance

— Most states permit minors to consent to prenatal care without parental notification; know your state's law

— IPV screening must occur without the partner in the room — a safety standard; document privately

— Suspected child abuse, certain communicable diseases (syphilis, HIV, hepatitis B/C — varies by state); neonatal abstinence syndrome reporting varies — substance use during pregnancy triggers child welfare reporting in some states (CAPTA Plans of Safe Care), which can deter care-seeking

— Counsel patients on what is and isn't reported; advocate for treatment-not-punishment framework

— Verify Rh status and document RhoGAM at every Rh-negative patient's chart — missed RhoGAM is a classic preventable harm

— Ensure prenatal records are transmitted to the delivery hospital by 36w

— Medication reconciliation at each visit (especially insulin, antihypertensives, anticoagulants)

Step 3 management: When a pregnant patient discloses intimate partner violence, the immediate priorities are (1) validate and assess safety, (2) provide local DV hotline and shelter resources, (3) develop a safety plan, (4) document carefully (may be subpoenaed), and (5) do not notify the partner. Reporting to law enforcement is the patient's decision in most states unless a weapon injury is involved.

Informed consent for routine interventions:

Confidentiality and adolescent patients:

Mandatory reporting:

Transition-of-care safety:

Vaccine refusal: address concerns, provide CDC materials, document; do not dismiss patient

Cultural humility: dietary, modesty, and decision-making preferences vary; use professional interpreters (not family) for limited-English-proficiency patients

High-Yield Associations and Rapid-Fire Clinical Facts

Board pearl: The single highest-yield 28-week intervention consistently tested is the combination of RhoGAM + Tdap + GCT — a question stem describing an Rh-negative 28-week patient is almost always testing whether you remember anti-D Ig.

Step 3 management: Verify that the prenatal care plan addresses all four: screening (GCT/CBC/STIs), prophylaxis (RhoGAM/aspirin), immunization (Tdap/flu/COVID/RSV), and counseling (kick counts, warning signs).

Rh-negative + 28w = RhoGAM 300 mcg IM (after confirming antibody screen negative)

27–36w = Tdap every pregnancy — maximize transplacental antibody for neonatal pertussis protection

32–36w during RSV season (Sep–Jan) = maternal RSV vaccine (Abrysvo) OR nirsevimab to infant after birth — not both

GCT 50g threshold ≥140 mg/dL → 3-hour 100g OGTT; OGTT ≥2 abnormal values (95/180/155/140) = GDM

Hgb <11 in 1st/3rd trimester = anemia; iron deficiency is the most common cause

Aspirin 81 mg from 12–16w for high-risk patients reduces preeclampsia by ~15–25%

Chronic HTN target <140/90 per CHAP trial — no increase in SGA

Live vaccines contraindicated in pregnancy: MMR, varicella, LAIV, smallpox, yellow fever (relative)

ACE-I, ARBs, direct renin inhibitors, statins, warfarin, methotrexate, isotretinoin, valproate = avoid in pregnancy

First-line antihypertensives in pregnancy: labetalol, nifedipine, methyldopa (hydralazine and IV labetalol for acute severe BP)

MgSO₄ neuroprotection if delivery <32w; betamethasone if 24–34w (consider 34–36+6w late preterm)

GBS culture at 36 0/7 – 37 6/7w; penicillin IV in labor if positive (or unknown with risk factors)

Fundal height = GA ±2 cm between 20–36w

Fetal HR normal 110–160 bpm; kick counts ≥10 in 2h

Postpartum 75g 2h OGTT at 4–12 weeks in GDM patients

Pregnancy increases VTE risk 4–5× — symptoms warrant Doppler/CT-PA without hesitation

TOLAC counseling for prior low-transverse cesarean; success rate ~70%, uterine rupture ~0.5–1%

Board Question Stem Patterns

Board pearl: The trap on a 28-week stem is forgetting that multiple interventions are due simultaneously — when given a "which of the following" with several correct answers, look for "all of the above" or the most time-sensitive (usually RhoGAM in Rh-negative patients).

Stem 1: A 32-year-old G2P1 at 28 weeks, blood type O-negative, antibody screen negative. → Answer: Administer anti-D immune globulin 300 mcg IM today; also order GCT, CBC, Tdap

Stem 2: 28-week visit, BP 148/94 (was 118/74 in first trimester), no proteinuria, no symptoms. → Answer: Repeat BP in 4 hours; if persistently elevated, diagnose gestational hypertension, obtain preeclampsia labs (CBC, AST/ALT, Cr, urine P/Cr), close follow-up

Stem 3: 28w GCT result 165 mg/dL. → Answer: 3-hour 100g OGTT; do not start insulin yet

Stem 4: 28w patient reports decreased fetal movement for 12 hours. → Answer: NST (not "reassure and kick counts" — that's prevention, not response to an active complaint)

Stem 5: 28w patient with prior preterm birth at 32 weeks, currently asymptomatic. → Answer: continue vaginal progesterone, counsel preterm labor signs; no role for routine cervical length at 28w if surveillance was reassuring through 24w

Stem 6: 28w, fundal height 24 cm. → Answer: ultrasound for fetal growth, amniotic fluid, placenta

Stem 7: 28w patient with type 1 DM, A1c 7.2%. → Answer: growth ultrasound today; antenatal testing twice weekly starting 32w; intensify glycemic control; continue aspirin

Stem 8: 28w patient asks about flu vaccine in October. → Answer: inactivated flu vaccine today (any trimester; LAIV contraindicated)

Stem 9: 28w patient with BP 168/112 and headache. → Answer: send to L&D, IV labetalol or hydralazine, magnesium sulfate, betamethasone, plan for delivery if severe features persist after stabilization

Stem 10: Patient declines Tdap citing prior dose 2 years ago. → Answer: recommend Tdap; given every pregnancy to maximize neonatal antibody transfer; document discussion if declined

One-Line Recap

The 28-week prenatal visit is the third-trimester gateway where every patient receives gestational diabetes screening, repeat CBC and antibody screen, Tdap vaccination, anti-D immune globulin if Rh-negative, fetal movement counseling, and a transition to every-2-week visit cadence — with risk-stratified additions (aspirin for preeclampsia prevention, growth ultrasounds for medical comorbidities, antenatal testing planning) layered on top.

Board pearl: If you remember only one triad for the 28-week visit, make it GCT + RhoGAM + Tdap — these three are the most heavily tested deliverables and the most common omissions in real-world prenatal care.

CCS pearl: Build the 28-week case as a workflow — vitals → fetal heart tones → screening labs → vaccines/RhoGAM → counseling → 2-week follow-up. Each component is a discrete order that earns credit; advance the clock between order entry and result review.

Universal at 28w: GCT, CBC, antibody screen, BP/urine/fundal height/FHTs, Tdap (27–36w), kick count counseling, preterm labor and preeclampsia warning signs

Rh-negative + antibody-negative: RhoGAM 300 mcg IM

High-risk: continue aspirin 81 mg; serial growth ultrasounds; plan antenatal testing from 32w; MFM as indicated

Escalate immediately if: BP ≥160/110, severe-feature symptoms, bleeding, PPROM, regular contractions, decreased fetal movement — send to L&D

Next steps: return every 2 weeks; GBS at 36w; RSV vaccine 32–36w if seasonal; delivery planning by 36w; postpartum visit and OGTT (if GDM) at 4–12 weeks

Pitfalls to avoid: forgetting RhoGAM, deferring Tdap to postpartum, missing an asymptomatic hypertensive trend, performing digital cervical exam in undiagnosed previa, neglecting depression and IPV screens