What assessments and interventions should be performed during a routine prenatal visit for a gravida 2, para 1 woman?

Routine Prenatal Visit for G2P1 Woman

All pregnant women should undergo comprehensive laboratory screening at the first prenatal visit, including complete blood count, blood typing with antibody screen, hepatitis B surface antigen, HIV, syphilis, rubella immunity, urinalysis, and cervical cultures with Pap smear, followed by gestational diabetes screening at 24-28 weeks and ongoing assessment of maternal weight, blood pressure, fundal height, and fetal heart rate at each visit. 1, 2

First Prenatal Visit Assessments

Essential Laboratory Testing

• Complete blood count to screen for anemia and establish baseline hematologic parameters 1, 2
• Blood typing and antibody screen (ABO and Rh) to identify potential blood incompatibilities and determine need for RhoGAM if Rh-negative 1, 2, 3
• Hepatitis B surface antigen to recognize and reduce risk of mother-to-child transmission 1, 2
• HIV antibody testing for all pregnant women 1, 2
• Syphilis serology to detect and treat maternal infection 1, 2
• Rubella antibody status to assess immunity 1, 2
• Urinalysis to screen for asymptomatic bacteriuria and proteinuria 4, 5
• Cervical cultures for gonorrhea and chlamydia with Pap smear according to routine screening guidelines 1

Risk Assessment for Gestational Diabetes

• Perform immediate glucose testing if high-risk features present: marked obesity (BMI ≥30), previous gestational diabetes, strong family history of diabetes, prior macrosomic infant (>4.05 kg), high-risk ethnicity (Hispanic, Native American, South/East Asian, African American, Pacific Islander), or polycystic ovary syndrome 4, 6
• If not high-risk, plan for standard screening at 24-28 weeks using 50-gram glucose challenge test or oral glucose tolerance test 4, 1, 6
• Low-risk women (age <25 years, normal pre-pregnancy weight, no family history, not high-risk ethnicity) may not require screening 4, 6

Genetic Screening and Counseling

• Offer combined first trimester screening (11-14 weeks) including nuchal translucency ultrasound, pregnancy-associated plasma protein A, and free beta-hCG, which achieves 85-90% detection rate for Down syndrome 2
• Assess family history for genetic disorders, chromosomal abnormalities, or ethnic-specific conditions (cystic fibrosis, sickle cell disease, Thalassemia) and offer carrier screening as indicated 4, 5
• Women ≥35 years should be offered amniocentesis or chorionic villus sampling for definitive diagnosis 2

Clinical Assessments at Each Visit

• Maternal weight to monitor appropriate gestational weight gain 4, 5
• Blood pressure to screen for hypertensive disorders 4, 5
• Fundal height measurement starting at 20 weeks to assess fetal growth 5
• Fetal heart rate auscultation starting when audible by Doppler (10-12 weeks) 5

Second Trimester Interventions (14-28 weeks)

Low-Dose Aspirin Prophylaxis

• Initiate 81 mg aspirin daily between 12-28 weeks (optimally before 16 weeks) for women at increased risk of preeclampsia, including chronic hypertension, pregestational diabetes, renal disease, autoimmune disease, or prior preeclampsia 4

Anatomic Survey

• Detailed fetal anatomy ultrasound at 18-22 weeks to screen for structural abnormalities 4
• Fetal echocardiogram if pregestational diabetes present 4

Maternal Serum Alpha-Fetoprotein Screening

• Offer MSAFP screening at 16-18 weeks for detection of open neural tube defects (75-90% detection rate) and anencephaly (95% detection rate) if not done with first trimester screening 1, 2
• Alternatively, quadruple marker test (AFP, hCG, unconjugated estriol, inhibin A) can be offered at 16-18 weeks for combined aneuploidy and neural tube defect screening 2

Gestational Diabetes Screening

• All women should undergo screening at 24-28 weeks using either one-step approach (75-gram OGTT) or two-step approach (50-gram glucose challenge test followed by 100-gram OGTT if threshold exceeded) 4, 1, 6
• Women with high-risk features who tested negative at first visit should be retested at 24-28 weeks 4, 6

Third Trimester Interventions (28-40 weeks)

Repeat Laboratory Testing

• Repeat complete blood count at 28 weeks to reassess for anemia 4
• Repeat HIV and syphilis screening at 28-32 weeks in high-risk populations 4
• Group B Streptococcus screening at 35-37 weeks via vaginal-rectal swab 4

RhoGAM Administration

• Administer RhoGAM at 28 weeks if mother is Rh-negative and antibody screen is negative 3
• Repeat dose within 72 hours postpartum if infant is Rh-positive 3

Fetal Surveillance

• Antepartum fetal surveillance starting at 32-34 weeks (nonstress test, amniotic fluid assessment, or biophysical profile) if pregestational diabetes or other high-risk conditions present 4
• Serial fetal growth ultrasounds if growth restriction suspected or high-risk conditions present 4

Delivery Planning

• Ultrasound for fetal growth assessment in third trimester to guide delivery timing and mode 4
• Consider cesarean delivery if estimated fetal weight ≥4500 grams in diabetic women 4

Common Pitfalls to Avoid

• Failing to screen for hepatitis B in first trimester, which is crucial for preventing vertical transmission and ensuring appropriate neonatal prophylaxis 1, 2
• Delaying glucose screening in high-risk women beyond first visit, as early detection allows for timely intervention to reduce complications 4, 6
• Missing RhoGAM administration at 28 weeks in Rh-negative women, which can lead to alloimmunization and hemolytic disease in future pregnancies 3
• Not recognizing that a weakly positive Du test late in pregnancy may indicate large fetomaternal hemorrhage requiring more than standard RhoGAM dose 3
• Overlooking the need for expanded baseline testing in women with chronic hypertension (liver enzymes, renal function, uric acid) or pregestational diabetes (A1C, TSH, creatinine, urine albumin-to-creatinine ratio), which are essential for detecting superimposed complications 4, 1