The STI Tests Built Into Prenatal Care

What STIs are on the standard prenatal panel?

The routine prenatal panel screens every pregnant person for HIV, syphilis, and hepatitis B at the first prenatal visit, regardless of stated risk. Chlamydia and gonorrhea are added for anyone aged under 25 or with other risk factors, and hepatitis C screening is now recommended in every pregnancy too. These are the infections national guidelines fold into early pregnancy care because each is treatable and each can pass to the baby. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.2Ref 2Centers for Disease Control and Prevention (2024).Getting Tested for STIs.That pregnancy screening is recommended, that most STIs are asymptomatic (supporting screening over symptom-watching), and that self-collection options exist for chlamydia and gonorrhea samples.

Most of the panel is a single blood draw. Blood tests cover HIV, syphilis, and hepatitis B and C. A urine sample or vaginal swab covers chlamydia and gonorrhea. Almost all of these infections are silent — the reason they are screened for rather than waited on is that the asymptomatic sti majority would otherwise go undetected until a complication appeared. 2Ref 2Centers for Disease Control and Prevention (2024).Getting Tested for STIs.That pregnancy screening is recommended, that most STIs are asymptomatic (supporting screening over symptom-watching), and that self-collection options exist for chlamydia and gonorrhea samples. Because the blood tests are bundled into a single draw, adding syphilis, HIV, and hepatitis rarely means an extra needle — they run from the same tubes; only the chlamydia and gonorrhea sample is separate, since it comes from urine or a swab rather than blood. 2Ref 2Centers for Disease Control and Prevention (2024).Getting Tested for STIs.That pregnancy screening is recommended, that most STIs are asymptomatic (supporting screening over symptom-watching), and that self-collection options exist for chlamydia and gonorrhea samples.

The prenatal panel is built to find silent infections early enough to treat them before they reach the baby.

Why syphilis is tested, sometimes more than once

Syphilis is on the panel because it can cross the placenta and cause congenital syphilis — infection passed to the fetus that can lead to stillbirth, newborn death, or serious lasting harm, and that is preventable when the pregnant person is treated in time. 3Ref 3Centers for Disease Control and Prevention (2024).About Congenital Syphilis.That syphilis can pass to a fetus during pregnancy, causing stillbirth, infant death, or severe outcomes, and that treatment during pregnancy prevents it — the rationale for testing and retesting syphilis. National rates have climbed, which is part of why testing rules have tightened. 3Ref 3Centers for Disease Control and Prevention (2024).About Congenital Syphilis.That syphilis can pass to a fetus during pregnancy, causing stillbirth, infant death, or severe outcomes, and that treatment during pregnancy prevents it — the rationale for testing and retesting syphilis.

Everyone is tested at the first visit. People at higher risk, or who live where syphilis is common, are generally retested early in the third trimester (around 28 weeks) and again at delivery, so a new infection later in pregnancy is not missed. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence. The deeper story of stds during pregnancy risks to baby belongs to the clinical guide on stis in pregnancy; here the point is narrower — syphilis is the test most likely to be drawn more than once. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.

How the HIV test in pregnancy works

The HIV test in pregnancy is usually a laboratory antigen/antibody blood test — the same fourth-generation test used outside pregnancy — offered on an opt-out basis at the first visit. It detects the p24 antigen plus HIV antibodies and becomes reliable roughly 18 to 45 days after an exposure. 4Ref 4Centers for Disease Control and Prevention (2024).Clinical Testing Guidance for HIV.That the laboratory antigen/antibody HIV test detects p24 antigen plus antibodies and becomes reliable roughly 18 to 45 days after exposure, so an early negative does not rule out a recent infection. A negative early test does not rule out a very recent infection, which is one reason higher-risk pregnancies are retested in the third trimester. 4Ref 4Centers for Disease Control and Prevention (2024).Clinical Testing Guidance for HIV.That the laboratory antigen/antibody HIV test detects p24 antigen plus antibodies and becomes reliable roughly 18 to 45 days after exposure, so an early negative does not rule out a recent infection.1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.

A single early negative can also miss an infection acquired during the pregnancy itself, which is the other reason higher-risk pregnancies are checked again later. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence. If someone arrives in labor never having been screened, a rapid test may be run and then confirmed with a laboratory test. The goal across all of these is the same — to identify HIV early in pregnancy, when there is the most time to act on it.

Chlamydia and gonorrhea: who is screened and rescreened

Chlamydia and gonorrhea are screened in pregnant people under 25, and in those 25 and older who have risk factors, at the first prenatal visit. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.5Ref 5Centers for Disease Control and Prevention (2024).About Chlamydia.That chlamydia is a common, frequently asymptomatic bacterial STI that can cause complications if untreated — supporting screening rather than symptom-watching during pregnancy. Anyone screened who is under 25 is generally retested in the third trimester, following the same sti screening frequency logic used outside pregnancy, because reinfection is common and both infections are usually symptomless. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.

Chlamydia is one of the most common reportable infections and is frequently 'silent,' which is exactly why a screening test rather than symptom-watching is used. 5Ref 5Centers for Disease Control and Prevention (2024).About Chlamydia.That chlamydia is a common, frequently asymptomatic bacterial STI that can cause complications if untreated — supporting screening rather than symptom-watching during pregnancy. The sample is a first-catch urine or a vaginal swab, and a self-collected swab is an accepted option. If you are not sure these were included, asking for the full panel at your visit is reasonable — the components genuinely vary by age and history. 2Ref 2Centers for Disease Control and Prevention (2024).Getting Tested for STIs.That pregnancy screening is recommended, that most STIs are asymptomatic (supporting screening over symptom-watching), and that self-collection options exist for chlamydia and gonorrhea samples.

What is not routinely on the prenatal STI panel

Not every STI is part of routine prenatal screening, and knowing the gaps lets you ask a precise question instead of assuming. Three that people often expect to be included — genital herpes, trichomoniasis, and HPV — are generally handled differently, tested for a specific reason rather than screened in everyone.

• Genital herpes. National guidance does not recommend routine blood (serologic) herpes testing for people without symptoms, including during pregnancy, because the blood test yields too many false positives to work as a screen. 6Ref 6Centers for Disease Control and Prevention (2024).Screening for Genital Herpes.That routine serologic (blood) herpes screening is not recommended for asymptomatic people, including in pregnancy, and that herpes testing is reserved for lesions or a clear clinical reason. Herpes is tested when there are sores or a clear clinical reason. 6Ref 6Centers for Disease Control and Prevention (2024).Screening for Genital Herpes.That routine serologic (blood) herpes screening is not recommended for asymptomatic people, including in pregnancy, and that herpes testing is reserved for lesions or a clear clinical reason.
• Trichomoniasis. Not screened routinely; it is generally tested when there are symptoms or when a person is living with HIV. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.
• HPV and the Pap test. Cervical cancer screening follows its own age-based schedule and is a separate thing from the STI panel, even when it happens at the same visit.

The same reasoning explains why a panel is not simply run for everything: a screen is worth doing where a positive would change care and where the test is accurate enough to trust, which is exactly why routine herpes blood testing is left off. 6Ref 6Centers for Disease Control and Prevention (2024).Screening for Genital Herpes.That routine serologic (blood) herpes screening is not recommended for asymptomatic people, including in pregnancy, and that herpes testing is reserved for lesions or a clear clinical reason. A prenatal panel is a defined set, not a scan for every possible infection. That is not a gap in care — it is how screening is designed to work.

When each prenatal STI test is repeated

Most of the panel is drawn once, at the first visit. What gets repeated depends on age, risk, and local prevalence — the same reasoning that sets sti screening frequency outside pregnancy, applied to the months you are pregnant. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.

HIV, syphilis, and hepatitis B are screened in every pregnancy, not only the higher-risk ones. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.

If you change partners during pregnancy or have a new exposure, that is worth mentioning, because it can change what is retested and when. 1Ref 1Centers for Disease Control and Prevention (2021).STI Screening Recommendations.Pregnancy screening recommendations: universal first-visit testing for HIV, syphilis, and hepatitis; chlamydia and gonorrhea screening for those under 25 or at risk; and third-trimester and delivery retesting based on age, risk, and local prevalence.