SEO Title: CCS Prenatal Visit Cases | OB Routine Care Step 3 (2026)
Meta Description: Master CCS prenatal visit workflow: initial labs, trimester screening, GDM testing, GBS protocols, Rh management, and counseling.
Target Keywords: CCS prenatal visit, CCS OB routine visit, step 3 CCS prenatal care, CCS prenatal labs
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The CCS prenatal visit is a core case type that tests your ability to manage routine antenatal care across all three trimesters. Whether you're seeing a patient at 8 weeks for initial labs or at 36 weeks for GBS screening, examiners expect you to know exactly which tests to order, when to order them, and how to counsel your patient. Mastering the prenatal visit workflow will prepare you for the high-yield OB management cases that appear consistently on Step 3 exams. This guide walks you through the complete prenatal protocol.
First Trimester: Initial Prenatal Visit (8-12 weeks)
Essential Baseline Labs
Order these labs at the initial visit—they establish your baseline and guide management throughout pregnancy:
• Blood type and Rh status: Critical for managing Rh-negative pregnancy and blood bank compatibility
• Complete Blood Count (CBC): Screen for anemia (Hgb <10.5 g/dL in first trimester may indicate need for iron supplementation or investigation of other causes)
• Antibody screen: Detect red cell alloimmunization
• Infectious disease screening:
◦ Rubella IgG (immunity; if seronegative, counsel on MMR postpartum)
◦ Hepatitis B surface antigen (HBsAg)
◦ Hepatitis C antibody
◦ HIV-1/2 antibody (and repeat in third trimester if high-risk)
◦ Rapid plasma reagin (RPR) or syphilis serology
• Urinalysis (UA): Baseline; screen for protein, glucose, nitrites, leukocyte esterase
• Urine culture: Screen for asymptomatic bacteriuria (present in 2-10% of pregnancies; untreated, increases risk of pyelonephritis and preterm birth)
• Pap smear (if due): Concurrent with prenatal evaluation
> Study Tip: The StudyCCS question bank includes 15+ prenatal visit cases where you must order the correct labs at each trimester encounter. Real-time scoring shows exactly where you earn and lose points on test selection.
Counseling at Initial Visit
• Prenatal vitamins: Folic acid 400 mcg daily (or 5 mg if history of neural tube defect); many recommend 600-800 mcg DFE from prenatal vitamin
• Iron supplementation: Not routine until second trimester (avoid GI upset in first trimester); 27 mg/day ferrous sulfate standard dosing
• Lifestyle: Eliminate alcohol, tobacco, and illicit drugs; discuss caffeine (data suggest <200 mg/day safe)
• Nutrition: Emphasize balanced diet with attention to calcium, DHA, and choline
• Work/Activity: Reassure that most activities safe; avoid high-impact sports or contact sports
• Sexual activity: Safe throughout uncomplicated pregnancy
Second Trimester: 16-20 Week Anatomy Scan and Screening
First Trimester Combined Screening (11-14 weeks) — Often Completed by OB
If your CCS case involves first-trimester screening completion:
• Nuchal translucency (NT) ultrasound: Measures fluid thickness at back of fetal neck; combined with maternal serum markers to assess Down syndrome, Edward syndrome, and Patau syndrome risk
• Maternal serum markers: PAPP-A (pregnancy-associated plasma protein A) and free beta-hCG
> Practice Alert: Prenatal screening and test result counseling are highest-yield CCS topics. The StudyCCS question bank includes cases where you must counsel patients on abnormal screening results and arrange appropriate follow-up testing.
Second Trimester Quad Screen (15-22 weeks)
If not done in first trimester, offer quad screen:
• Alpha-fetoprotein (AFP): Elevated in Down syndrome (trisomy 21), elevated in neural tube defects
• Free beta-hCG: Elevated in Down syndrome
• Unconjugated estriol (uE3): Decreased in Down syndrome
• Inhibin A: Elevated in Down syndrome
If abnormal results (e.g., 1 in 50 risk or higher for aneuploidy):
• Order cell-free fetal DNA testing (cfDNA) or noninvasive prenatal testing (NIPT) for further risk stratification
• If high-risk persists on NIPT or patient declines NIPT, offer amniocentesis (15-18 weeks) for definitive diagnosis
18-20 Week Anatomic Survey
• Confirm dates if discrepant with last menstrual period (LMP)
• Assess biometry (femur length, head circumference)
• Visualize all organ systems
• Assess amniotic fluid volume, placental location
• Screen for structural anomalies
Management of incidental findings:
• Soft markers (echogenic intracardiac focus, choroid plexus cyst): usually benign; may increase risk if multiple markers present
• Structural anomalies (cleft lip, heart defect, renal abnormality): arrange detailed fetal echocardiography, involve maternal-fetal medicine (MFM), deliver at tertiary care center
Third Trimester: Glucose Tolerance Testing and Late Prenatal Management
Gestational Diabetes Mellitus (GDM) Screening (24-28 weeks)
Standard approach:
• 1-hour glucose tolerance test (GTT): All pregnant patients; threshold 140 mg/dL (90% specificity)
• If 1-hour GTT ≥140 mg/dL: Order 3-hour fasting glucose tolerance test
◦ Fasting glucose >95 mg/dL, 1-hour >180, 2-hour >155, 3-hour >140 (need 2 abnormal values for diagnosis of GDM)
Management of GDM:
• Refer to nutrition/dietitian for medical nutrition therapy (MNT)
• Daily home glucose monitoring (fasting and 2-hour postprandial)
• If lifestyle modification inadequate (fasting >95 or 2-hour postprandial >120 mg/dL), initiate insulin or metformin
• Monitor fetal growth (20-25% increased risk of macrosomia and shoulder dystocia)
• Repeat glucose tolerance test at 6 weeks postpartum (GDM resolves, but 50% progress to type 2 DM within 10 years)
Group B Streptococcus (GBS) Screening (35-37 weeks)
• Rectovaginal swab: Culture for GBS
• If positive: Administer intrapartum penicillin G benzathine 5 million units IV load, then 2.5 million units IV q4h during labor
• If penicillin allergy:
◦ Non-severe (rash only): Cefazolin 2g IV load, then 1g IV q8h
◦ Severe (anaphylaxis, angioedema): Vancomycin 1g IV q12h or clindamycin 900mg IV q8h (if susceptible)
• If GBS bacteriuria during pregnancy: Treat (indicates risk for ascending infection) and administer IAP
• If unknown GBS status at delivery: Administer IAP
> Study Tip: GBS screening and intrapartum antibiotic prophylaxis protocols are frequently tested on CCS. The StudyCCS question bank includes labor cases where you must decide timing and dosing of GBS coverage.
Blood Pressure Monitoring and Preeclampsia Surveillance
At every visit, measure blood pressure:
• Baseline in first trimester: Establish patient-specific baseline (pregnant patients have lower BP than non-pregnant)
• Gestational hypertension: Systolic ≥140 or diastolic ≥90 on two occasions after 20 weeks (no proteinuria)
• Preeclampsia: Hypertension + proteinuria (≥0.3 g/24 hours) OR symptoms (headache, RUQ pain, visual changes, cerebral/pulmonary edema)
Management of hypertension in pregnancy:
• First-line agents: Labetalol (safe in all trimesters), nifedipine extended-release (NIFEDIPINE ER)
• Avoid: ACE inhibitors, ARBs (teratogenic in first trimester; renal injury in second/third trimester)
• If preeclampsia with severe features: Admit for magnesium sulfate (seizure prophylaxis), delivery planning (may be indicated)
Rh-Negative Pregnancy Management
RhoGAM Administration Schedule
• First trimester (threatened abortion, ectopic, molar pregnancy): 50-100 mcg IM
• Second or third trimester antepartum: 300 mcg IM at 28 weeks; if sensitizing event (amniocentesis, CVS, trauma, bleeding), give 300 mcg or calculated dose
• Postpartum: Administer within 72 hours if infant is Rh-positive or blood type unknown
Indirect Coombs Test
Perform at initial visit and at 28 weeks (and prior to RhoGAM administration) to detect alloimmunization. If positive before 28 weeks → MFM referral for titration and possible amniocentesis.
Vaccination in Pregnancy
Safe Vaccines (Inactivated)
• Influenza vaccine: All pregnant patients every pregnancy (protects mother and neonate via passive immunity)
• Tdap: One dose per pregnancy (preferably third trimester to maximize antibody transfer)
• COVID-19 vaccine: Safe and recommended; can be given at any trimester
Contraindicated (Live Vaccines)
• MMR, varicella, rotavirus, live attenuated influenza vaccine (LAIV): Defer until postpartum
Anemia Management
Iron deficiency is most common cause:
• Diagnosis: Hemoglobin <10.5 g/dL in first/second trimester, <10 g/dL in third trimester
• First-line: Iron supplementation (ferrous sulfate 325 mg daily is standard; may increase to BID if tolerated)
• If inadequate response: Screen for other causes (B12 deficiency, folate deficiency, hemolysis, chronic disease)
• If severe anemia (Hgb <7 g/dL) and delivery imminent: Transfusion consideration in consultation with obstetrics
Common Third Trimester Issues
Gestational Hypertension and Preeclampsia
See BP monitoring section above; deliver at 37 weeks (or earlier if severe features).
Preterm Labor (20-37 weeks)
• Signs: Regular uterine contractions + cervical change OR cervical dilation >2 cm
• Management: Admission, fetal monitoring, tocolytics (nifedipine, terbutaline), betamethasone for fetal lung maturity if 24-34 weeks
• Antibiotics: Ampicillin + gentamicin + clindamycin if rupture of membranes (ROM)
Rupture of Membranes
• Confirm with fern test, pooling, nitrazine paper
• If <34 weeks: Admission, sterile precautions, betamethasone, antibiotics (ampicillin + gentamicin; add clindamycin)
• If >34 weeks: Deliver (risk of infection outweighs benefit of extending pregnancy)
Complete Order Set for Each Trimester Visit
First Trimester (8-12 weeks)
Labs: Blood type, Rh, CBC, syphilis serology, HIV, Hepatitis B/C, Rubella IgG, Pap smear (if due), UA, urine culture
Ultrasound: Dating ultrasound + nuchal translucency (if offering first-trimester screening)
Prescriptions: Prenatal vitamin (folic acid 400-600 mcg), address medications
Counseling: Lifestyle, nutrition, exercise, supplement use
Second Trimester (16-22 weeks)
Labs: Quad screen if not done first trimester; repeat CBC if anemia concern
Ultrasound: 18-20 week anatomy scan
Prescriptions: Iron supplementation if not already started; continue prenatal vitamin
Counseling: Results of screening, nutrition, activity, danger signs
Third Trimester (28 weeks)
Labs: CBC (repeat), consider repeat HIV if high-risk, RhoGAM if Rh-negative
Screening: GDM screen (1-hour GTT); if positive, arrange 3-hour GTT
Vaccines: Influenza and Tdap (if not given in earlier visits)
Counseling: Fetal kick counts, danger signs, delivery planning
Third Trimester (35-37 weeks)
Labs: GBS rectovaginal culture; CBC if anemia concern
Ultrasound: Assessment of presentation (vertex vs breach/transverse)
Counseling: Signs of labor, delivery plan, postpartum care, breastfeeding education
2-Minute Screen
In the prenatal clinic, prioritize:
1. Vital signs: BP (gestational hypertension?), weight gain (excessive or inadequate?)
2. Fundal height: Consistent with dates? Excessive (polyhydramnios, macrosomia) or small (oligohydramnios, IUGR)?
3. Edema: Symmetric lower extremity or facial/hand swelling (preeclampsia)?
4. Fetal heart rate: Present and reassuring?
5. Symptoms: Any vaginal bleeding, abdominal pain, headache, visual changes, shortness of breath?
Don't-Miss Diagnoses
• Preeclampsia with Severe Features: Seizure and maternal/fetal death risk; requires ICU admission and delivery planning
• Gestational Diabetes: Uncontrolled hyperglycemia increases macrosomia, shoulder dystocia, and neonatal hypoglycemia risk
• Group B Streptococcus Infection (Untreated): Risk of neonatal sepsis, meningitis, death; intrapartum antibiotics reduce risk by 85%
• Rh Sensitization: Hemolytic disease of fetus and newborn if undetected and untreated; requires intensive monitoring
• Preterm Labor: 10% of deliveries; betamethasone and antibiotics significantly reduce neonatal mortality
• Abruption/Preterm Premature Rupture of Membranes (PPROM): Vaginal bleeding or fluid leakage—always evaluate
Related Articles
• CCS Well-Child Visit: Pediatric Preventive Care Cases on Step 3
• CCS Acute Kidney Injury: Floor Management & Workup
• CCS Heart Failure: Acute Decompensation vs Chronic Management
Ready to practice? The StudyCCS question bank includes 25+ prenatal visit cases covering all three trimesters, screening dilemmas, and delivery planning with real-time scoring. Test your skills on initial labs, GDM management, and GBS protocols today.