What are the recommended schedule and components of prenatal visits during pregnancy?

Prenatal Care Schedule and Components

Initiate prenatal care at or before 10 weeks gestation, as early care significantly improves maternal and infant outcomes, with the first visit being the most comprehensive and subsequent visits following a risk-stratified schedule. 1

Initial Prenatal Visit (Ideally ≤10 weeks)

Medical History and Risk Assessment

• Obtain complete medical history including reproductive history, previous pregnancy complications, chronic medical conditions, current medications, and family history for genetic risk stratification 2, 3
• Screen for psychosocial risk factors including housing insecurity, social support, intimate partner violence, substance use (alcohol, tobacco, drugs), depression, anxiety, and food insecurity 3, 1
• Document reproductive life plan and assess for high-risk conditions requiring specialized care 2, 3

Physical Examination

• Perform focused examination including periodontal assessment (periodontal disease increases preterm delivery risk), thyroid, cardiac, breast, and pelvic examinations 2, 3, 1
• Measure baseline blood pressure and document pre-pregnancy or current body mass index (BMI >25 kg/m² increases risk of gestational diabetes, hypertension, miscarriage, and stillbirth) 1

Laboratory Testing

• Universal screening: Complete blood count, urinalysis, blood type and Rh screen, rubella immunity, hepatitis B surface antigen, syphilis (RPR or VDRL), HIV 2, 3, 4
• Risk-based screening: Gonorrhea and chlamydia for women <25 years or at increased risk, varicella immunity if uncertain, thyroid-stimulating hormone (especially for women with diabetes or thyroid symptoms), cervical cytology if due 2, 3, 4
• Genetic screening: Offer chromosomal/genetic disorder screening based on family history, ethnic background, and maternal age ≥35 years 3, 1
• Screen for asymptomatic bacteriuria (decreases preterm delivery and intrauterine growth restriction risk) 1

Interventions and Counseling

• Prescribe prenatal vitamins containing 400-800 mcg folic acid (reduces neural tube defects) and 150 mcg potassium iodide, ideally started preconception 2, 3, 1
• Treat iron deficiency anemia if identified (decreases preterm delivery, intrauterine growth restriction, and perinatal depression risk) 1
• Administer influenza vaccine if pregnant during flu season and not previously vaccinated 3, 1
• Counsel on nutrition emphasizing "five-a-day" (two servings fruit, three servings vegetables), adequate hydration, healthy weight management, and safe food preparation 3
• Recommend regular moderate exercise appropriate for pregnancy 2, 3
• Strongly advise complete avoidance of alcohol, tobacco, recreational drugs, teratogenic medications (ACE inhibitors, statins, isotretinoin, warfarin, certain antiseizure medications), hot tubs, and hyperthermia 2, 3
• Establish medical home with emergency contact instructions and after-hours care access 3

Subsequent Visit Schedule

Standard Schedule (Low-Risk Pregnancies)

The traditional schedule of 12-14 visits (monthly until 28 weeks, biweekly until 36 weeks, then weekly until delivery) has remained unchanged since 1930 despite lack of supporting evidence, and alternative risk-stratified schedules are being evaluated 2

Key Interval Visits and Screening

12-16 weeks:

• Initiate low-dose aspirin (81-150 mg daily) for women at high risk of preeclampsia (chronic hypertension, previous preeclampsia, diabetes, renal disease, autoimmune disease, multiple gestation) 3, 1

15-20 weeks:

• Offer maternal serum alpha-fetoprotein and anatomy ultrasound screening 3

24-28 weeks:

• Universal screening for gestational diabetes using 1-hour glucose challenge test or 2-hour oral glucose tolerance test 2, 3, 1
• Administer Rho(D) immune globulin at 28 weeks for RhD-negative patients (decreases alloimmunization risk) 1

27-36 weeks:

• Administer Tdap vaccine (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) to provide infant protection against pertussis; optimal timing is during each pregnancy regardless of previous vaccination 2, 3, 1

36-37 weeks:

• Test for group B Streptococcus colonization; initiate intrapartum antibiotic prophylaxis if positive to decrease neonatal infection risk 3, 1

Third trimester (high-risk pregnancies):

• Perform ultrasound for fetal growth assessment 3
• Initiate antepartum fetal surveillance at 32-34 weeks for high-risk conditions 3

Ongoing Monitoring Throughout Pregnancy

• Monitor blood pressure and screen for proteinuria at each visit (preeclampsia surveillance) 3, 1
• For women with preexisting diabetes: perform dilated eye examination before pregnancy or in first trimester, then every trimester and for 1 year postpartum 2, 3
• For women with diabetes: monitor fasting and postprandial glucose with targets of fasting <95 mg/dL and either 1-hour postprandial <140 mg/dL or 2-hour postprandial <120 mg/dL 2, 3
• Rescreen for syphilis in third trimester and at delivery for high-risk women; no infant should be discharged without maternal syphilis status determination 4

Special Populations Requiring Enhanced Care

Women with Preexisting Diabetes

• Achieve A1C <6.5% prior to conception (reduces congenital anomalies, preeclampsia, preterm birth) 2, 3
• Involve multidisciplinary team including endocrinologist, maternal-fetal medicine specialist, registered dietitian, and diabetes educator 2, 3
• Plan delivery timing: 39 0/7 to 39 6/7 weeks with good glycemic control; 36 0/7 to 38 6/7 weeks with poor control or vascular complications 3

Advanced Maternal Age (≥35 years)

• Increased risk for gestational diabetes, hypertension, miscarriage, intrauterine growth restriction, aneuploidy, birth defects, and stillbirth requires enhanced surveillance 1

Critical Pitfalls to Avoid

• Failing to initiate care before 10 weeks misses the critical window for optimal outcomes and early interventions 1, 5
• Inadequate preconception counseling for women with chronic conditions (diabetes, hypertension, thyroid disease) increases maternal and fetal complications 2, 3
• Missing psychosocial risk screening at the initial visit overlooks social determinants of health that significantly impact outcomes 3, 1
• Forgetting to rescreen high-risk women for syphilis in third trimester and at delivery can result in missed congenital syphilis 4
• Delaying Tdap administration beyond 36 weeks or omitting it entirely leaves infants vulnerable to pertussis in early life 2, 1
• Not treating periodontal disease when identified misses an opportunity to decrease preterm delivery risk 1
• Failing to administer Rho(D) immune globulin at 28 weeks to RhD-negative patients increases alloimmunization risk 1