4 Pregnancy and Prenatal Care

Purpose and timing of prenatal care

Prenatal care promotes the health of the pregnant patient and developing fetus, identifies risks early, and supports informed choices. Care is individualized: visit frequency, tests, and referrals depend on health history, pregnancy findings, patient preferences, and access to care.

Begin care as soon as pregnancy is recognized. Patients may accept or decline screening after counseling.

Routine visits and assessment

At the first visit, the clinician typically reviews menstrual and pregnancy history, medical and family history, medications and supplements, mental health, and social needs. The visit also includes estimating gestational age and the due date and assessing risk factors. Bringing a medication list and available vaccination and prior-pregnancy records can support this review.

At visits, care commonly includes checking blood pressure, reviewing symptoms and questions, monitoring weight as appropriate, and assessing fetal growth and well-being as pregnancy advances. Ultrasound and additional appointments are selected according to clinical need and patient preference. When appropriate, care may combine in-person and remote visits.

Screening and assessment

Screening looks for increased risk or a condition that may need follow-up; a screening result is not necessarily a diagnosis. Before testing, explain its purpose, timing, possible results, and next steps.

• First prenatal visit: Common tests include a complete blood count, blood type and Rh status, urine testing and culture, and infection screening such as HIV, hepatitis B and C, and syphilis. Other tests depend on history and risk. These assessments can identify anemia, Rh incompatibility, asymptomatic bacteriuria, and infections that can affect pregnancy or newborn care.

• Early pregnancy: Offer carrier screening and prenatal genetic screening options. These assess the chance of selected inherited conditions or fetal chromosomal conditions, and patients may accept or decline. Cell-free DNA is a screening test, not a diagnosis. A positive result warrants counseling and discussion of diagnostic testing, such as chorionic villus sampling or amniocentesis.

• 18–22 weeks: Offer fetal anatomic ultrasound to screen for major structural differences, regardless of the choice of chromosome screening.

• 24–28 weeks: Screen for gestational diabetes; repeat a blood count or other tests when indicated. These assessments can identify conditions for which treatment or monitoring may reduce complications.

• Around 28 weeks, if Rh-negative: Repeat antibody assessment and offer Rh(D) immune globulin when indicated to reduce the risk of Rh sensitization.

• Third trimester: Repeat infection screening when recommended by guidelines, local requirements, or individual risk. Assess blood pressure and symptoms throughout pregnancy for hypertensive disorders that may emerge later.

• 36–37 weeks: Perform a vaginal–rectal Group B streptococcus (GBS) culture to identify patients who may need antibiotics during labor to reduce the newborn’s risk of GBS disease.

Preeclampsia screening relies on blood-pressure assessment throughout pregnancy and evaluation of concerning symptoms. For patients at increased risk, the clinician may recommend low-dose aspirin after reviewing eligibility and timing. The care team may also screen for depression, anxiety, intimate partner violence, and social needs, and connect patients with support.

Nutrition, activity, and substance safety

Encourage a varied, nutrient-rich diet and a prenatal supplement appropriate to the patient. Folic acid is especially important before conception and in early pregnancy; 400–800 micrograms daily is commonly recommended for people who may become pregnant. Some conditions or medications require a different dose, so patients should consult a clinician. Discuss food safety, including avoiding unpasteurized products and thoroughly heating deli meats and hot dogs.

Discuss healthy weight gain based on pre-pregnancy body mass index, fetal growth, and individual circumstances. For most uncomplicated pregnancies, moderate activity is encouraged, with a common goal of at least 150 minutes per week. Patients should confirm activity plans with the care team, especially if they have medical conditions or pregnancy complications.

Advise patients to avoid alcohol, tobacco and nicotine products, cannabis, and non-prescribed drugs. There is no known safe amount or time for alcohol use during pregnancy. Patients should review prescription medicines, over-the-counter products, supplements, and workplace or environmental exposures with a clinician before starting or stopping them. Offer nonjudgmental help and treatment resources for substance use.

Vaccination and preparation

Review recommended vaccines with the care team. Tdap is recommended during each pregnancy, preferably at 27–36 weeks. Seasonal influenza vaccination and maternal RSV vaccination may be appropriate according to current recommendations, season, and eligibility.

Live vaccines such as MMR and varicella are generally avoided during pregnancy. Review immunity and postpartum vaccination needs. Hand hygiene, safer sex, and food-safety practices also help prevent infection.

Discuss birth preferences, breastfeeding, infant care, and postpartum planning. Ask about transportation, housing, food access, safety, language needs, and emotional support, and connect patients with appropriate resources.

Recognizing urgent warning signs

Patients should contact their maternity care team promptly for vaginal bleeding, fluid leaking, severe or persistent abdominal pain, severe headache, vision changes, fever, difficulty breathing, chest pain, or markedly reduced fetal movement after movements are regularly felt.

For a life-threatening emergency, seek emergency care. Patients should know whom to call after hours and should not wait for a routine appointment when urgent symptoms occur.