Updated for 2026
WHNP prenatal care: routine prenatal screening and obstetric complication management
Prenatal care is a core WHNP competency. Certification exams test the routine prenatal visit schedule and components, first and second trimester genetic and anatomic screening, management of common obstetric complications including preeclampsia, gestational diabetes, and preterm labour, and ACOG evidence-based guidelines.
Educational purpose: This content is for exam preparation and professional development only. It is not intended for clinical decision-making. Always follow current guidelines, institutional policies, and scope of practice.
Routine prenatal care schedule and components
Prenatal visit frequency (ACOG): Every 4 weeks until 28 weeks; every 2–3 weeks from 28–36 weeks; weekly from 36 weeks to delivery. Low-risk pregnancies may use fewer visits in some protocols, but most US practices follow traditional schedule.
Initial prenatal visit (<12 weeks): Complete history, blood group and Rh type, antibody screen, CBC, rubella immunity, hepatitis B surface antigen, VDRL/RPR, HIV (with consent per state law), chlamydia/gonorrhoea NAAT, TSH (if symptomatic or high-risk), urine culture, Pap smear (if due), carrier screening counselling. Initiate folic acid 0.4–0.8 mg daily (started preconceptionally if possible); 4 mg if prior neural tube defect history.
First trimester genetic screening (10–13 weeks): Combined screening: nuchal translucency (NT) ultrasound + PAPP-A + free β-hCG = 82–87% detection rate for trisomy 21. Cell-free fetal DNA (cfDNA/NIPT): highest sensitivity and specificity (99%+ for trisomy 21, 18, 13); positive predictive value depends on baseline risk. Offer to all pregnant patients (ACOG 2022). Positive cfDNA requires diagnostic confirmation: CVS (10–13 weeks) or amniocentesis (15–20 weeks).
Second trimester screening: Maternal serum quad screen (AFP, hCG, estriol, inhibin A) at 15–20 weeks if cfDNA not done. Anatomy ultrasound at 18–22 weeks — evaluation of all organ systems, placenta, amniotic fluid, cervical length. GBS culture at 35–37 weeks.
Preeclampsia — ACOG diagnostic criteria and management
Preeclampsia diagnosis (ACOG 2019): Gestational hypertension (BP ≥140/90 on 2 occasions ≥4 hours apart, after 20 weeks) PLUS at least one of: proteinuria (≥300 mg/24h, protein:creatinine ratio ≥0.3, or 2+ on dipstick), thrombocytopaenia (<100,000), renal insufficiency (creatinine >1.1 or doubled), impaired liver function (LFTs twice normal), pulmonary oedema, headache not responsive to analgesia, visual disturbances.
Severe features: Systolic ≥160 or diastolic ≥110 on 2 occasions ≥4 hours apart (or severe BP once if treatment given), thrombocytopaenia <100,000, LFTs ≥2× ULN with RUQ/epigastric pain, progressive renal insufficiency, pulmonary oedema, new-onset headache not responding to analgesia, visual disturbances.
Management: Antihypertensive treatment for severe-range BP (>160/110): IV labetalol or hydralazine; oral nifedipine immediate-release. Magnesium sulfate for seizure prophylaxis in preeclampsia with severe features (loading dose 4–6 g IV over 15–20 minutes, maintenance 1–2 g/hr). Monitor for magnesium toxicity: loss of deep tendon reflexes (>9 mEq/L), respiratory depression (>12 mEq/L). Antidote: calcium gluconate IV. Definitive treatment: delivery — gestational age determines timing.
HELLP syndrome: Severe preeclampsia variant: Haemolysis + Elevated Liver enzymes + Low Platelets. Obstetric emergency. Management: magnesium sulfate, antihypertensives, delivery.
Frequently asked questions
- What is the ACOG recommendation for aspirin use in preeclampsia prevention?
- USPSTF (2021) and ACOG recommend low-dose aspirin (81 mg/day) as preventive treatment for preeclampsia in high-risk women. Initiate at 12–28 weeks (optimally before 16 weeks) and continue until delivery. High-risk criteria for recommendation: History of preeclampsia (especially early onset or severe), multifetal gestation, renal disease, autoimmune disease (SLE, antiphospholipid syndrome), type 1 or 2 diabetes, chronic hypertension. Moderate-risk criteria (consider aspirin with ≥2 factors): nulliparity, obesity (BMI >30), family history of preeclampsia, Black race (due to structural racism and health inequities that increase risk), age ≥35, socioeconomic factors, prior adverse pregnancy outcomes. Combined calcium supplementation (1–2 g/day) reduces risk in women with low calcium intake. Aspirin acts by inhibiting thromboxane A2 while sparing prostacyclin — improving uteroplacental blood flow.
Clinically reviewed by NurseNest Clinical Review Team · Last updated 2026-06-10 · For educational purposes only · Review policy