OB Guideline 8: Antenatal Care

Initial Visit

When possible, the initial visit to the obstetrical provider should be scheduled in the first trimester. The visit should include a detailed evaluation of the patient and their history to assess and plan for the pregnancy. At a minimum, the initial assessment should encompass:

1. A detailed history, including:
   • Past and current illnesses
   • Surgeries
   • Allergies
   • Family history including genetic history, and ethnicity
   • Prior pregnancies
   • A menstrual history, with specific attention for accurate dating of the pregnancy
   • Medications and supplements currently being taken
   • Psychosocial history (mental health, depression; alcohol, tobacco and drug use; type of work; relationship status; intimate partner violence)
   • Environmental and occupational exposure history
2. Screening for current psychosocial concerns:
   • Depression: screen using a standardized, validated instrument
   • Living situation
   • Safety/intimate partner violence.
3. Counseling about:
   • Normal course of pregnancy
   • Frequency of visits, office hours
   • When and how to contact the clinician
   • Balanced nutrition, recommended weight gain based on BMI, vitamin supplementation, and foods and beverages to avoid
   • Exercise
   • Sexual activity
   • Environmental hazards
   • Health maintenance (e.g., dental health, appropriate use of seat belts)
   • HIV and recommendations for testing
   • Suggested readings
   • Recommended vaccinations: influenza, Tdap, hepatitis A&B, and Pneumovax 23, if at risk
   • Substance abuse or abuse screening, including tobacco, alcohol, and drugs, with interventions offered, as appropriate
4. Genetic counseling, including:
   • Providing information about targeted and expanded screening options
   • Offering testing for cystic fibrosis and spinal muscular atrophy (SMA) to all patients
   • Offering testing as appropriate for ethnicity including:
     • Tay Sachs testing, such as for patients of Ashkenazi Jewish , French-Canadian, or Cajun descent
     • Canavan’s disease and familial dysautonomia screening, such as for patients of Ashkenazi Jewish descent
     • Hemoglobin electrophoresis for those at risk for hemoglobin disorders, such as for patients of Asian, African, Caribbean, or Mediterranean descent
     • Others as appropriate to history, family history or ethnicity 
   • Offering counseling on methods available to screen or test for fetal aneuploidy, including non-invasive prenatal testing (NIPT) in the first trimester
5. A detailed physical examination that includes blood pressure, height, weight and breast, heart, lung, abdominal, and pelvic examinations.
6. Establish the estimated date of delivery (see Guideline 7)
7. Recommended laboratory testing, including:
   • Complete blood count (CBC) with indices
   • Blood group and Rh type determination
   • Antibody screen
   • Rubella immunity status (unless previously documented or adequate vaccination documented)
   • Hepatitis B screening
   • Hepatitis C screening
   • HIV testing (unless declined by patient)
   • Syphilis screening²
   • Varicella immunity status (if not known)
   • Urine culture
   • Baseline urine screening
   • Genetic carrier screening (as selected by patient)
   • Cervical cytology (if appropriate)
   • Gonorrhea and chlamydia screening
   • Diabetes screening (if indicated)
8. Identified medical problems and risk factors should be addressed and a problem list created.
9. Folic acid or prenatal vitamin containing adequate folic acid should be advised.

Subsequent Visits

At every routine prenatal visit, an interval history should be obtained. Assessment should be made of the patient’s weight, blood pressure, and uterine size. Urine testing for protein and glucose should be obtained if indicated. Fetal assessment should include heart sounds and movement as appropriate for gestational age. Fetal presentation should be assessed in the late third trimester.

Testing in the second and third trimesters:

• Fetal survey ultrasound may be performed at 17–20 weeks
• TB testing should be performed in the early second trimester if indicated
• CBC, glucose, and Syphilis screening, if appropriate, at 24–28 weeks
• Antibody testing should be performed in Rh negative patients at 28–30 weeks and as indicated
• STD testing should be repeated at 32–36 weeks for patients at risk
• Group B Streptococcus screening should be done, if appropriate, at 35–38 weeks (see Guideline 12)
• HIV testing should be re-offered if declined at the first visit or for patients at high risk

Counseling in the second and third trimester may include:

• Offering a fetal survey ultrasound
• Reviewing instructions on when and how to contact the clinician
• Reviewing and discussing informed consent for labor and delivery
• Reviewing and discussing the health care proxy
• Reviewing warning signs of preterm labor
• Reviewing expected fetal movements
• Preparing for childbirth including availability of childbirth classes, analgesic options, and expectations during labor and birth
• Discussing and encouraging breastfeeding, including available community supports and resources
• Selecting a pediatrician
• Newborn care topics, including circumcision, infant care classes, infant CPR classes, car seats
• Postpartum recovery including postpartum appointments, parental leave, depression, and contraception

Additional interventions:

• During flu season, influenza vaccine should be recommended to pregnant patients
• During RSV season. RSV vaccine should be recommended in the third trimester
• COVID-19 vaccine
• TdaP vaccine should be recommended in the third trimester
• Other vaccinations may be considered in pregnancy as indicated (e.g., hepatitis B vaccination for patients at risk)
• Rh immunoglobulin should be provided for Rh negative birthing person at approximately 28–30 weeks gestation, or as indicated (bleeding, trauma, or amniocentesis, external version); and postpartum as indicated

1. Massachusetts Health Quality Partners. 2025 Perinatal care guidelines. MHQP. Published September 3, 2025. Accessed December 10, 2025. https://www.mhqp.org/resources/clinical-guidelines/perinatal-careguidelines/
2. American College of Obstetricians and Gynecologists. Screening for syphilis in pregnancy. ACOG Practice Advisory. April 2024. Reaffirmed 2025. Accessed December 10, 2025. https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2024/04/screening-forsyphilis-in-pregnancy