From the Guidelines
Third trimester care should prioritize monitoring maternal and fetal health, preparing for delivery, and addressing common concerns, with prenatal visits every 2-3 weeks until 36 weeks, then weekly until delivery, as recommended by recent guidelines 1. The key points for third trimester prenatal care include:
- Monitoring maternal blood pressure, as hypertension risk increases during this period
- Measuring fundal height to assess fetal growth
- Determining fetal position to prepare for delivery
- Conducting fetal heart rate checks to ensure fetal well-being
- Routine screening for Group B Streptococcus at 35-37 weeks, with treatment using intravenous penicillin G if positive 1
- Daily monitoring of fetal movements, with immediate reporting of decreased activity
- Tdap vaccination between 27-36 weeks to provide passive immunity to the newborn Common third trimester concerns that should be addressed include:
- Heartburn, treated with lifestyle modifications and antacids
- Lower back pain, managed with proper body mechanics and support
- Leg cramps, improved with hydration and stretching
- Sleep disturbances, which can be mitigated with relaxation techniques and sleep hygiene practices Women should be aware of warning signs that require immediate attention, such as:
- Vaginal bleeding
- Severe headaches
- Visual changes
- Sudden swelling
- Contractions before 37 weeks
- Rupture of membranes
- Decreased fetal movement Birth planning, including delivery preferences and pain management options, should be discussed with healthcare providers during this period to ensure a safe delivery, with consideration of the most recent guidelines and evidence-based practices 1.
From the Research
Key Points for Third Trimester Prenatal Care
- Screening for gestational diabetes between 24 and 28 weeks is recommended for all patients 2, 3
- Testing for group B Streptococcus should be performed between 36 and 37 weeks, and intrapartum antibiotic prophylaxis should be initiated to decrease the risk of neonatal infection 2
- People at risk of preeclampsia, including those diagnosed with COVID-19 in pregnancy, should be offered 81 mg of aspirin daily starting at 12 weeks 2
- Routine immunizations for all pregnant women include influenza vaccine; tetanus toxoid, reduced diphtheria, acellular pertussis (Tdap) vaccine 2, 3
- Women with risk factors should be screened in the first trimester for gestational diabetes mellitus 3
- Induction of labor may be offered to women with chronic medical conditions before 41 weeks, based on the condition and relative risks and benefits of continued pregnancy 3
- Women without maternal or fetal indications should not be offered elective delivery before 39 weeks, but should be offered induction at 41 weeks with a recommendation for delivery before 42 weeks 3
- Routine third-trimester ultrasonography does not reduce adverse perinatal outcomes in low-risk pregnancies 4
- Third-trimester repeat HIV testing is recommended for individuals known to be at high risk of acquiring HIV, but some studies suggest that universal third-trimester repeat HIV testing may be beneficial in reducing perinatal transmission 5
- Prenatal yoga exercises may improve sleep quality in third-trimester pregnant women 6
Additional Recommendations
- Identification and treatment of periodontal disease decreases preterm delivery risk 2
- Treatment of iron deficiency anemia decreases the risk of preterm delivery, intrauterine growth restriction, and perinatal depression 2
- Ancestry-based genetic risk stratification using family history can inform genetic screening 2
- Folic acid supplementation (400 to 800 mcg daily) decreases the risk of neural tube defects 2
- All pregnant patients should be screened for asymptomatic bacteriuria, sexually transmitted infections, and immunity against rubella and varicella 2
- Universal screening for depression, anxiety, intimate partner violence, substance use, and food insecurity is recommended early in pregnancy 2