Chapter 29. Fetal Assessment and Prenatal Diagnosis

Rhesus type, antibody screen

Screen for antibodies that may result in hemolytic disease of the newborn. Rh- women should receive anti(D)-immune globulin prophylaxis (current recommendations are at 28 wk and at delivery, as well as with any invasive procedure in which maternal–fetal circulation can mix such as amniocentesis or CVS)

CBC

Screen for anemia, hemoglobinopathies

Rubella immunity screen

Nonimmune patients should be immunized postpartum (not during pregnancy!)

RPR

Treatment of mother and infant may be indicated for positive serologies (see chapter 38)

HepBsAg

Immunoprophylaxis at delivery for positive serologies

UA and urine culture

Treatment of asymptomatic bacteria indicated in pregnancy due to increased risk of perinatal morbidity, preterm labor

Cervical cytology

If not done within 6 months of pregnancy

Chlamydia and gonorrhea endocervical specimen

Repeat testing if initial results are positive, in women <25 yr old, and high-risk women

HIV

ACOG recommends universal screening with an “opt-out” strategy

OGTT

24–28 wk

Should be done in first trimester in women with risk factors (obesity, prior history of GDM, prior macrosomic infant)

Repeat STD screening (RPR, HepBsAg, Chlamydia and gonorrhea)

Third trimester

Only women at continued risk and those who acquired a new risk factor during pregnancy

CBC, antibody screening

Early third trimester

Vaginal and rectal swab for GBS

35–37 wk

Also in the event of PPROM as outlined below

Disease

Test

Comments

Bacterial vaginosis

Not recommended for routine screening

HCV

HCV antibody screening

No recommended screening date; done at first prenatal visit

Screen only patients at high risk for disease (IVDU, blood products, liver disease)

HSV

Not recommended for routine screening

Thyroid dysfunction

TSH, free T4

Controversial; ACOG and Endocrine Society recommend testing only for women who are symptomatic, have a personal or family history of disease, or are otherwise at high-risk

Because of the possible adverse impact on neurologic development of undetected hypothyroidism, others recommend universal screening

Tuberculosis

PPD placement

Pregnant women should be tested in accordance with guidelines established for nonpregnant patients.

Toxoplasmosis

Toxoplasmosis IgG and IgM serologies

Routine screening of pregnant women is controversial and often not performed in the US

Varicella

Varicella serologies

Test all pregnant women; provide counseling for seronegative women and postpartum varicella vaccine