Clinical High-Yield · 10 min read · April 28, 2026
Obstetrics and prenatal care is a consistently tested section on the FNP boards, and it rewards organized, systematic preparation. The boards test a predictable set of content: the prenatal lab schedule, the management of gestational diabetes and preeclampsia, and the essentials of postpartum care. Here's the high-yield content organized by trimester.
The initial prenatal visit (ideally at 8–10 weeks) includes a comprehensive lab panel. Know which tests are done and why.
Routine first-trimester labs:
Rh sensitization: Rh-negative women with an Rh-positive partner receive RhoGAM (Rh immunoglobulin) at 28 weeks and within 72 hours of delivery. Also given after any potentially sensitizing event: miscarriage, ectopic pregnancy, amniocentesis, abdominal trauma.
Folic acid: 400–800 mcg/day starting at least 1 month before conception and continuing through the first trimester prevents neural tube defects. Women with a prior NTD-affected pregnancy take 4 mg/day.
Medications to avoid in pregnancy: The boards test teratogens. Key ones: isotretinoin (severe birth defects — requires iPLEDGE program), valproate (neural tube defects), ACE inhibitors (fetal renal dysplasia in 2nd/3rd trimester), warfarin (embryopathy in 1st trimester, fetal hemorrhage in 3rd trimester), tetracyclines (tooth discoloration), fluoroquinolones (cartilage damage — avoid), methotrexate (abortifacient and teratogen).
15–20 weeks: Quad screen (maternal serum AFP, hCG, estriol, inhibin A) screens for trisomy 21, trisomy 18, and neural tube defects. AFP interpretation: elevated AFP → neural tube defect or abdominal wall defect; decreased AFP → trisomy 21 or 18.
18–20 weeks: Anatomy ultrasound — evaluates fetal anatomy, placental location, amniotic fluid volume, and fetal growth.
Amniocentesis: Offered to women ≥35 years (advanced maternal age) or those with abnormal screening. Performed at 15–20 weeks. Diagnoses chromosomal abnormalities, NTDs (elevated AFP in amniotic fluid), and some genetic disorders.
Board Pearl: The boards test the difference between screening tests (which give a risk estimate) and diagnostic tests (which give a definitive answer). Nuchal translucency + PAPP-A + free β-hCG is a screening test. Amniocentesis and CVS (chorionic villus sampling) are diagnostic tests.
**Gestational Diabetes ...