Quick answer: Chlamydia during pregnancy is common, usually causes no symptoms, and is safely curable with antibiotics — most often a single dose of azithromycin, which is the preferred option in pregnancy. Left untreated, it can raise the risk of preterm birth, low birth weight, and passing the infection to your baby during delivery (causing eye or lung infections). The good news: routine prenatal screening catches it, treatment is safe and effective, and a follow-up "test of cure" confirms it's gone. If you've just tested positive while pregnant, you're doing everything right by reading this.

Why testing happens in pregnancy

Chlamydia is the most common bacterial STI, and because it's usually silent, most people don't know they have it. That's why testing for chlamydia is a standard part of prenatal care — typically at your first prenatal visit, and again later in pregnancy if you're under 25 or have other risk factors. It's not a judgment; it's routine care that protects both you and your baby.

The risks if it's left untreated

Untreated chlamydia in pregnancy is linked to:

  • Preterm birth (delivering early)
  • Premature rupture of membranes (your water breaking early)
  • Low birth weight
  • Passing the infection to your baby during a vaginal delivery, which can cause:
    • Conjunctivitis (eye infection) — usually 1–2 weeks after birth
    • Pneumonia (lung infection) — usually within a few months

Here's the reassuring part: these risks come from untreated infection over time. Caught and treated during pregnancy, chlamydia is very unlikely to harm your baby.

Which treatment is safe in pregnancy?

The antibiotics used outside pregnancy aren't all safe during it — but there's a well-established, safe option:

  • Azithromycin (a single 1 g dose) is the preferred treatment in pregnancy. It's effective and considered safe.
  • Amoxicillin is an alternative in some cases.
  • Doxycycline is avoided in pregnancy (it's the go-to for non-pregnant adults, but not used during pregnancy).

Your clinician will choose based on your situation. Whatever you take, finish it as directed. For more on how the antibiotics compare, see our guide to chlamydia treatment.

Why a "test of cure" matters here

Outside of pregnancy, a routine re-test to confirm the infection cleared usually isn't needed. In pregnancy, it is. A test of cure — repeat testing about 4 weeks after treatment — is recommended to make sure the infection is gone, because the stakes for your baby are higher. Many clinicians also re-test again later in pregnancy, since reinfection is possible.

What about your partner?

Your recent sexual partners need treatment too — otherwise you can be reinfected, which restarts the risk. Avoid sex until 7 days after both you and your partner have completed treatment. Many clinics can help notify partners discreetly.

Frequently asked questions

Can chlamydia cause a miscarriage? Chlamydia is more strongly linked to preterm birth and low birth weight than to miscarriage, but any untreated infection in pregnancy is worth treating promptly. Early treatment removes the risk.

Is the treatment safe for my baby? Yes — azithromycin is the preferred option specifically because it's considered safe in pregnancy. The bigger risk to your baby is leaving the infection untreated, not the antibiotic.

Can I still have a vaginal birth? Usually yes. The concern is passing the infection during delivery — which treatment (confirmed by a test of cure) prevents. Your care team will guide you.

Will my baby be tested? If there's any concern, newborns can be monitored for eye or lung infections and treated quickly if needed. Treating you during pregnancy is what prevents this in the first place.

Testing positive for anything while pregnant can feel scary — but chlamydia is one of the most straightforward parts of prenatal care to handle. It's common, it's curable, and treating it protects your baby. If you want to talk it through with people who get it, our community is here for you.