Quick Answer
STDs can pass to babies during childbirth through contact with infected blood, vaginal secretions, or lesions. Syphilis crosses the placenta anytime during pregnancy; herpes transmits during vaginal delivery if active lesions; HIV transmits through birth canal fluids; gonorrhea and chlamydia infect the baby's eyes during passage.
- Syphilis: crosses placenta at any stage — treatment with penicillin prevents congenital syphilis.
- Herpes: C-section recommended if active lesions or prodromal symptoms present at delivery.
- HIV: ART during pregnancy + IV during labor + infant prophylaxis + formula feeding = <1% transmission.
- Gonorrhea/chlamydia: treating the parent before delivery prevents neonatal conjunctivitis.
Context Most Pages Skip
The question of whether to deliver vaginally or by C-section depends on the specific infection and its activity at delivery.
What to ask your OB
By the time you deliver, you should know: your HIV/syphilis/hepatitis B status, whether you have active genital herpes, and whether you were treated for chlamydia/gonorrhea. If any of these are unknown, testing is urgent.
Sources & Further Reading
- CDC — Sexually Transmitted Infections
- CDC STI Treatment Guidelines
- WHO — Sexually transmitted infections fact sheet
- MedlinePlus — Sexually Transmitted Diseases
Figures reflect CDC surveillance and WHO estimates; they are population statistics, not personal risk predictions.