What are the necessary steps and medications for a prenatal visit for a woman of childbearing age with a relatively healthy medical history who is planning to become pregnant or is already pregnant?

Prenatal Care: Step-by-Step Protocol

Initial Visit (Ideally by 10 Weeks Gestation)

Begin prenatal care at or before 10 weeks gestation, as early initiation significantly improves maternal and fetal outcomes. 1

History Taking

Obtain the following specific information:

• Reproductive history: Previous pregnancy complications (preterm birth, preeclampsia, fetal loss, birth defects, low birth weight), number of prior pregnancies and outcomes, and any history of cesarean section 2, 3
• Medical conditions: Diabetes, hypertension, thyroid disease, autoimmune disorders, rheumatic heart disease, thromboembolism, seizure disorders, and psychiatric illness 2, 4
• Current medications: Identify and discontinue FDA pregnancy category X medications (isotretinoin, warfarin, certain antiseizure medications) and most category D medications unless maternal benefits outweigh fetal risks 2
• Family history: Genetic disorders, chromosomal abnormalities, neural tube defects, and ethnic background for carrier screening (cystic fibrosis, sickle cell, Tay-Sachs, thalassemia) 2, 4
• Substance use: Tobacco, alcohol, and recreational drugs using structured screening tools 2
• Psychosocial factors: Depression, anxiety, intimate partner violence, housing insecurity, and food insecurity 2, 3, 1

Physical Examination

Perform focused examination of:

• Periodontal assessment: Identify and treat periodontal disease, which decreases preterm delivery risk 2, 1
• Thyroid examination: Palpate for enlargement or nodules 2
• Cardiac examination: Assess for murmurs or signs of heart disease 2
• Breast examination: Evaluate for masses 2
• Pelvic examination: Assess uterine size, cervical appearance, and adnexal masses 2

Laboratory Testing - First Visit

Order the following comprehensive panel:

Hematologic:

• Complete blood count with differential and platelets 2, 5
• Blood type and Rh screen 2, 5

Metabolic:

• Comprehensive metabolic panel 5
• Urinalysis 2, 5
• Thyroid-stimulating hormone (TSH) 2, 5
• Hemoglobin A1C (if diabetes risk factors present) 2, 5

Infectious disease screening:

• HIV antibody/p24 antigen with reflex 2, 5
• Hepatitis B surface antigen 2, 5
• Hepatitis C antibody 5
• Syphilis (RPR or VDRL) 2, 5
• Rubella IgG antibody 2, 5
• Gonorrhea and chlamydia nucleic acid amplification test (cervical or urine) 2, 5

Additional testing when indicated:

• Varicella immunity (if no documented history of infection or vaccination) 2, 4
• Cervical cytology (if due per screening guidelines) 2
• QuantiFERON-TB Gold Plus (if risk factors present) 5
• Genetic carrier screening based on ethnicity and family history 2, 4

Medications to Prescribe

Prenatal vitamin with the following components: 3, 6

• Folic acid 400-800 mcg (0.4-0.8 mg) daily: Start immediately if not already taking; reduces neural tube defects by nearly 75% 3, 4, 7, 1
• Potassium iodide 150 mcg 3
• Iron (to prevent anemia) 3
• Vitamin B12 3
• Vitamin D 3
• Choline 3
• DHA (docosahexaenoic acid) 3

Low-dose aspirin 81 mg daily starting at 12-16 weeks for high-risk patients: 3, 1

• History of preeclampsia
• Chronic hypertension
• Diabetes (type 1 or 2)
• Renal disease
• Autoimmune disease
• Multifetal gestation

Immunizations at First Visit

Administer or update the following vaccines: 2, 3, 4

• Influenza vaccine (if pregnant during flu season and not previously vaccinated) 2, 3
• COVID-19 vaccine (if not up to date) 2, 3
• Hepatitis B vaccine series (if non-immune) 2, 4

Note: Rubella and varicella vaccines are live vaccines and contraindicated during pregnancy; administer postpartum if non-immune 4

Counseling and Education

Provide specific guidance on:

Nutrition: 2, 3, 4

• Consume five servings daily: two fruits and three vegetables
• Maintain adequate hydration
• Avoid fish high in mercury (shark, swordfish, king mackerel, tilefish)
• Practice safe food preparation to prevent toxoplasmosis and listeriosis

Lifestyle modifications: 2, 3, 4

• Complete abstinence from alcohol, tobacco, and recreational drugs (non-negotiable)
• Regular moderate exercise appropriate for pregnancy
• Avoid hot tubs and hyperthermia
• Always wear seatbelts

Weight management: 2, 4

• Target prepregnancy BMI 19.8-26.0 kg/m² for optimal outcomes
• Discuss appropriate gestational weight gain based on current BMI

Subsequent Visit Schedule

For low-risk pregnancies, schedule 8-14 visits: 3

• Every 4 weeks until 28 weeks
• Every 2 weeks from 28-36 weeks
• Weekly from 36 weeks until delivery

At each visit, assess: 3

• Blood pressure
• Fundal height (starting at 20 weeks)
• Fetal heart tones (starting at 10-12 weeks with Doppler)
• Maternal weight
• Urine protein (dipstick)

Second Trimester Testing (15-28 Weeks)

At 15-20 weeks:

• Maternal serum alpha-fetoprotein (MSAFP) or quad screen for neural tube defects and aneuploidy 2, 7
• Anatomy ultrasound at 18-20 weeks 3

At 24-28 weeks:

• Gestational diabetes screening: 1-hour 50g glucose challenge test (if ≥140 mg/dL, proceed to 3-hour 100g oral glucose tolerance test) or 2-hour 75g oral glucose tolerance test 2, 3, 5, 1
• Repeat complete blood count to screen for anemia 1

Third Trimester Testing (28+ Weeks)

At 27-36 weeks (ideally 27-32 weeks):

• Tdap vaccine (tetanus, diphtheria, acellular pertussis) - administer during every pregnancy to provide infant protection against pertussis 2, 3, 5

At 28 weeks (if Rh-negative):

• Antibody screen and administer RhoGAM 300 mcg if negative 1

At 36-37 weeks:

• Group B Streptococcus (GBS) vaginal-rectal culture: If positive, administer intrapartum antibiotic prophylaxis to decrease neonatal infection risk 1
• Repeat HIV and syphilis testing in high-risk populations 1

At 32-34 weeks for high-risk pregnancies:

• Begin antepartum fetal surveillance (non-stress tests or biophysical profiles) 3
• Ultrasound for fetal growth assessment 3

Special Populations Requiring Enhanced Care

Women with Preexisting Diabetes

Achieve A1C <6.5% prior to conception to reduce congenital anomalies, preeclampsia, and preterm birth. 2, 3

Multidisciplinary team involvement: 2, 3

• Endocrinologist
• Maternal-fetal medicine specialist
• Registered dietitian nutritionist
• Diabetes care and education specialist

Glucose monitoring targets: 2, 3

• Fasting glucose <95 mg/dL (5.3 mmol/L)
• 1-hour postprandial glucose <140 mg/dL (7.8 mmol/L) OR
• 2-hour postprandial glucose <120 mg/dL (6.7 mmol/L)

Additional screening: 2

• Dilated eye examination before pregnancy or in first trimester, then every trimester and for 1 year postpartum
• Serum creatinine and urine albumin-to-creatinine ratio
• ECG if age ≥35 years or cardiac risk factors present
• Lipid panel

Delivery timing: 3

• 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

Women with Chronic Hypertension

Target blood pressure <140/90 mm Hg using pregnancy-safe medications. 1

Discontinue ACE inhibitors and angiotensin receptor blockers immediately (FDA pregnancy category D/X). 2, 4

Initiate low-dose aspirin 81 mg daily at 12-16 weeks. 3, 1

Critical Pitfalls to Avoid

Inadequate preconception counseling for women with chronic conditions (diabetes, hypertension, thyroid disease) significantly increases maternal and fetal complications. 2, 3

Failure to screen for psychosocial risk factors (depression, intimate partner violence, substance abuse, food insecurity) misses critical opportunities for intervention. 2, 3, 1

Delaying Tdap administration beyond 36 weeks or omitting it entirely leaves infants vulnerable to pertussis in early life. 3

Administering folic acid doses >1 mg daily without ruling out vitamin B12 deficiency may mask pernicious anemia while allowing neurologic complications to progress. 6

Relying on clinical examination or home pregnancy tests alone to rule out early pregnancy is unreliable; always obtain laboratory confirmation. 8

Failing to identify and discontinue teratogenic medications (isotretinoin, warfarin, certain antiseizure medications, ACE inhibitors) before conception or in early pregnancy. 2, 4