Quick Answer

STDs during pregnancy affect both the parent and baby: untreated chlamydia and gonorrhea can cause preterm labor and eye infections in newborns, syphilis can cross the placenta at any stage, herpes can cause neonatal infection during delivery, and HIV transmits through pregnancy or birth without treatment. All of these are preventable with prenatal screening.

  • Chlamydia/gonorrhea: preterm birth risk; neonatal conjunctivitis (eye infection) visible within days of birth.
  • Syphilis: crosses the placenta causing congenital syphilis — stillbirth, bone deformities, neurologic damage.
  • Herpes: neonatal herpes is rare but devastating — transmission at delivery if active lesions.
  • HIV: vertical transmission rate drops from ~25% to <1% with appropriate ART.

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Prenatal STI screening is standard of care precisely because interventions work. Penicillin cures syphilis in pregnancy, antivirals prevent neonatal herpes, ART virtually eliminates HIV transmission, and antibiotics clear chlamydia/gonorrhea before delivery complications occur.

Screening schedule

First prenatal visit: HIV, syphilis, hepatitis B, chlamydia, gonorrhea. Third trimester re-screen for syphilis and HIV if high risk. Hepatitis C if risk factors present. Missing these tests is the main preventable cause of bad outcomes.

⚕️ This page is educational and does not replace advice from a licensed clinician. If you may have been exposed to an STI, get tested — most infections are manageable, and many are fully curable.

Sources & Further Reading

Figures reflect CDC surveillance and WHO estimates; they are population statistics, not personal risk predictions.