What are the key aspects of antenatal (prenatal) care during pregnancy?

Key Aspects of Antenatal Care During Pregnancy

Comprehensive antenatal care should begin ideally before conception or as early as possible in pregnancy (before 10 weeks), incorporating preconception optimization, systematic screening protocols, risk stratification for complications, trimester-specific interventions, and continuous monitoring through delivery planning. 1, 2

Preconception and Early Pregnancy Care (Before 10 Weeks)

Essential Supplementation and Medication Review

• Initiate folic acid 400-800 mg daily and potassium iodide 150 mg daily immediately upon pregnancy planning or confirmation to reduce neural tube defects and support fetal thyroid development. 3, 1, 2
• Review all current medications and discontinue teratogens including ACE inhibitors, angiotensin receptor blockers, statins, warfarin, valproic acid, and isotretinoin before conception. 3, 1
• For women with diabetes, achieve A1C <6.5% before conception to reduce congenital malformations from 1.4-10.9% to 1.0-1.7%. 3, 1

Initial Laboratory and Screening Tests

• Obtain complete blood count, blood type and Rh screen, rubella and varicella immunity status, syphilis serology, hepatitis B surface antigen, HIV testing (opt-out screening), gonorrhea and chlamydia screening, and urinalysis with urine culture. 3, 2
• Screen for thyroid disease with TSH measurement, particularly in women with diabetes or symptoms of thyroid dysfunction. 3
• Perform cervical cytology if due per routine screening guidelines. 3
• Test hemoglobin around 30 weeks gestation rather than early pregnancy, as high hemoglobin is a danger signal for adverse outcomes. 4

Immunization Updates

• Administer hepatitis B, rubella, varicella, and human papillomavirus vaccines as needed before conception (live vaccines contraindicated during pregnancy). 3
• Provide tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine during each pregnancy between 27-36 weeks. 2, 5
• Administer influenza vaccine during any trimester and COVID-19 vaccination regardless of trimester. 2, 5

Psychosocial and Lifestyle Assessment

• Screen universally for depression, anxiety, intimate partner violence, substance abuse (tobacco, alcohol, drugs including marijuana), and food insecurity at the initial visit and throughout pregnancy. 3, 2
• Use validated screening tools such as CAGE or T-ACE questionnaires for alcohol and substance abuse. 3
• Counsel on complete cessation of tobacco, alcohol, and all recreational drugs as these increase risks of preterm birth, low birthweight, and fetal anomalies. 3, 1, 2

Risk Stratification for Preeclampsia (12-16 Weeks)

Initiate low-dose aspirin 81 mg daily between 12-16 weeks (optimally before 16 weeks) and continue until 36 weeks for women with any major risk factor or ≥2 minor risk factors. 3, 1, 6, 2

Major Risk Factors (Any One Requires Aspirin)

• History of preeclampsia in prior pregnancy
• Chronic hypertension
• Pregestational diabetes (type 1 or type 2)
• Chronic kidney disease
• Antiphospholipid syndrome
• BMI ≥35 kg/m² 1, 7

Minor Risk Factors (≥2 Require Aspirin)

• Advanced maternal age (≥35 years)
• First-degree family history of preeclampsia
• Nulliparity or new paternity
• Short duration of sexual relationship with current partner
• Connective tissue disorders
• African American race 7

Second Trimester Care (14-28 Weeks)

Structural and Functional Assessments

• Perform detailed fetal anatomy ultrasound between 16-22 weeks to detect congenital anomalies including neural tube defects, cardiac defects, renal anomalies, and skeletal abnormalities. 3, 1, 6
• Schedule fetal echocardiogram between 16-22 weeks for women with pregestational diabetes due to increased risk of cardiac malformations and hypertrophic cardiomyopathy. 3, 1, 6

Gestational Diabetes Screening

• Screen all pregnant women for gestational diabetes between 24-28 weeks using 75-gram oral glucose tolerance test or two-step approach (50-gram screening followed by 100-gram diagnostic test if abnormal). 2, 5
• Screen earlier (at initial visit) for women with risk factors including BMI ≥25 kg/m², prior gestational diabetes, family history of diabetes, or high-risk ethnicity. 2

Ongoing Monitoring

• Continue low-dose aspirin for preeclampsia prophylaxis through 36 weeks. 1, 6
• Monitor blood pressure at each visit and assess for preeclampsia symptoms including new headache, visual disturbances, epigastric pain, and reduced fetal movements after 20 weeks. 1

Third Trimester Care (28-40 Weeks)

Infectious Disease Screening

• Test for group B Streptococcus colonization between 36-37 weeks via vaginal-rectal swab and provide intrapartum antibiotic prophylaxis if positive to prevent neonatal sepsis. 2
• Repeat HIV testing in third trimester for women in high-prevalence areas or with ongoing risk factors. 3

Fetal Surveillance for High-Risk Pregnancies

• Initiate antepartum fetal surveillance at 32-34 weeks for women with pregestational diabetes, chronic hypertension, prior stillbirth, fetal growth restriction, or other high-risk conditions using nonstress testing, biophysical profile, or modified biophysical profile. 3, 6, 7
• Perform serial ultrasounds for fetal growth assessment in women with diabetes, hypertension, or suspected growth abnormalities. 3, 6

Special Considerations for Diabetes

• For women with pregestational diabetes, establish multidisciplinary care including endocrinologist, maternal-fetal medicine specialist, registered dietitian nutritionist, and diabetes educator. 3, 7
• Monitor fasting glucose <95 mg/dL and either 1-hour postprandial <140 mg/dL or 2-hour postprandial <120 mg/dL. 1
• Perform dilated eye examinations each trimester and for 1 year postpartum due to risk of diabetic retinopathy progression. 3, 7

Delivery Planning (36-40 Weeks)

Timing of Delivery

• For women with good glycemic control and no vascular complications, plan delivery at 39 0/7 to 39 6/7 weeks. 3, 6
• For women with poor glycemic control, vascular complications, or prior stillbirth, consider delivery between 36 0/7 to 38 6/7 weeks based on individual risk assessment. 3, 6
• Consider cesarean delivery if estimated fetal weight ≥4500 grams to reduce risk of shoulder dystocia and birth trauma. 3
• Offer induction of labor at 41 weeks for all women, with recommendation for delivery before 42 weeks. 5

Nutritional and Lifestyle Counseling Throughout Pregnancy

Dietary Recommendations

• Promote balanced nutrition with at least 2 servings of fruit and 3 servings of vegetables daily ("five-a-day" approach). 1
• Provide comprehensive nutrition assessment addressing BMI extremes (obesity or underweight), meal planning, correction of dietary deficiencies, caffeine intake limitation, and safe food preparation techniques. 3, 1
• Supplement with calcium 1200 mg daily if dietary intake is inadequate. 7

Physical Activity and Safety

• Recommend regular moderate exercise such as brisk walking, swimming, or prenatal yoga appropriate for pregnancy stage. 3, 1
• Counsel on avoidance of hyperthermia (hot tubs, saunas) and ensuring adequate sleep. 3

Common Pitfalls to Avoid

• Failing to initiate aspirin prophylaxis before 16 weeks in high-risk women significantly reduces its effectiveness in preventing preeclampsia. 1, 7
• Delaying preconception counseling until after conception misses the critical window for optimizing glycemic control and preventing teratogen exposure during organogenesis (5-8 weeks gestation). 3
• Overlooking mental health screening at every visit can miss opportunities for early intervention in depression, anxiety, and intimate partner violence. 1, 6
• Inadequate preparation for delivery in women with high-risk conditions (diabetes, placenta accreta spectrum) without multidisciplinary planning increases maternal and neonatal morbidity. 6, 7
• Routine iron supplementation in well-nourished populations is unnecessary, but iron and folate should be provided in areas of high anemia prevalence. 4