Quick Answer

Several STDs increase miscarriage risk: syphilis causes stillbirth in up to 40% of untreated cases, bacterial vaginosis doubles the risk of second-trimester loss, and untreated chlamydia/gonorrhea may contribute through inflammation. Early prenatal screening and treatment reduce these risks to near-zero.

  • Syphilis: the most dangerous to pregnancy — up to 40% of untreated infections result in stillbirth.
  • BV: associated with 2x risk of second-trimester miscarriage and preterm delivery.
  • Chlamydia/gonorrhea: weaker evidence, but PID during pregnancy raises risks.
  • Treatment works: penicillin for syphilis, metronidazole for BV, ceftriaxone/azithromycin for chlamydia/gonorrhea.

Context Most Pages Skip

The mechanism is inflammation and placental damage. Untreated infections create a hostile uterine environment that can trigger contractions, premature rupture of membranes, or direct fetal infection.

After miscarriage

If you experienced a miscarriage and were not screened for STIs, consider testing now. Knowing whether an infection contributed helps guide future pregnancy planning and treatment.

⚕️ 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.