STD Testing During Pregnancy: What’s Tested and Why It Matters

STD testing in pregnancy follows a specific schedule tied to trimester and risk level — and it's more comprehensive than most pregnant women realize. All pregnant women should be tested for syphilis, HIV, chlamydia, gonorrhea, and hepatitis B at the first prenatal visit; hepatitis C is now recommended for all pregnant women; and repeat testing in the third trimester is indicated for syphilis, HIV, and gonorrhea in women with risk factors or in high-prevalence areas.

Why Prenatal STD Screening Is Critical

Untreated STDs in pregnancy cause outcomes that are entirely preventable with screening and treatment: congenital syphilis causes miscarriage, stillbirth, neonatal death, and severe neonatal disease; HIV vertical transmission to the newborn occurs without maternal ART; neonatal gonorrheal conjunctivitis (ophthalmia neonatorum) causes blindness; neonatal chlamydial pneumonia causes significant morbidity; hepatitis B transmission at delivery leads to chronic HBV in 90% of exposed neonates. The ongoing congenital syphilis crisis illustrates what happens when screening fails: over 3,700 congenital syphilis cases and 282 stillbirths in the US in 2022 — not because screening doesn't work, but because many affected women weren't receiving prenatal care.

First Prenatal Visit: What Should Be Tested

At the first prenatal appointment (ideally before 12 weeks): syphilis (RPR plus confirmatory treponemal test); HIV (4th generation Ag/Ab test); chlamydia (NAAT); gonorrhea (NAAT); hepatitis B surface antigen (HBsAg); hepatitis C antibody (anti-HCV) — recommended for all pregnant women regardless of risk factors since 2020; blood type and Rh factor; rubella immunity status; varicella immunity status. In higher-prevalence areas or for women with specific risk factors: trichomoniasis NAAT may also be added.

Third Trimester Repeat Testing: Who Needs It

Repeat testing at 28 to 36 weeks is indicated for: syphilis — for women in high-prevalence areas, women who use drugs, women with new or multiple partners, or women whose partners have multiple partners; HIV — for women at increased risk (new partner, sex work, IV drug use); gonorrhea and chlamydia — for women under 25 or with new partners since first trimester testing. All women without documented syphilis and HIV testing in the third trimester in high-prevalence jurisdictions (per CDC and state-specific recommendations).

At Delivery

Syphilis: all women should be tested at delivery if not tested in the third trimester; some state policies require testing at delivery regardless. HIV: rapid HIV testing at delivery for women with unknown HIV status or who are high-risk. Hepatitis B: HBsAg should be documented at delivery; newborns of HBsAg-positive mothers receive HBIG and hepatitis B vaccine within 12 hours of birth. GBS (Group B Streptococcus): rectal-vaginal swab at 36 to 38 weeks — this is NOT an STD test but is part of standard prenatal care and causes confusion; GBS is not sexually transmitted.

Treatment in Pregnancy

Syphilis: benzathine penicillin G is safe and effective in pregnancy; treatment before 36 weeks prevents congenital syphilis. HIV: ART throughout pregnancy prevents vertical transmission; cesarean delivery may be recommended if viral load is detectable near term. Chlamydia: azithromycin 1g single dose (doxycycline is contraindicated in pregnancy). Gonorrhea: ceftriaxone 500mg IM injection. Trichomoniasis: metronidazole 500mg twice daily for 7 days (single-dose regimen is less effective in pregnancy). All bacterial STDs diagnosed in pregnancy should be treated promptly — there is no safe waiting period.

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Frequently Asked Questions

Is STD testing mandatory during pregnancy?

In most US states, certain prenatal tests (including syphilis and HIV) are required or strongly recommended by law and public health guidelines. Syphilis testing is required at the first prenatal visit in all 50 states. Individual patients can decline tests, but providers are obligated to offer them.

Will my partner be tested too?

Partner testing is not part of routine prenatal care for the pregnant patient, but is strongly recommended if an STD is diagnosed. Untreated partners reinfect the pregnant patient, potentially undoing treatment. Expedited partner therapy (EPT) allows treatment of partners without requiring them to visit a clinic.

What if I find out I have an STD during pregnancy?

All bacterial STDs (chlamydia, gonorrhea, syphilis, trichomoniasis) diagnosed during pregnancy are curable with antibiotics safe in pregnancy. HIV is manageable with ART. Early diagnosis and treatment prevents virtually all vertical transmission and congenital disease. A positive result is not a disaster — it's the information needed to protect both you and your baby.

Related: Syphilis test in pregnancy · Chlamydia window period · STD testing near me · Get tested today

This article is for informational purposes only and does not constitute medical advice.