Chlamydia During Pregnancy: Screening, Safe Treatment & Risks

• About 70–80% of women with chlamydia have no symptoms, so screening — not how you feel — is the only reliable way to catch it in pregnancy.
• The pregnancy-safe treatment is a single 1 g dose of azithromycin, endorsed by NACO, FOGSI, ACOG and the CDC. Doxycycline (the usual non-pregnancy drug) is not used in pregnancy.
• Untreated chlamydia roughly doubles the risk of preterm birth and can be passed to the baby during vaginal birth, causing eye infection (conjunctivitis) or pneumonia.
• Your partner must be treated too — otherwise reinfection is common and undoes the benefit of your treatment.
• A test-of-cure 3–4 weeks after treatment is recommended in pregnancy, and testing is free at NACO STI clinics across India.

Chlamydia is an infection caused by the bacterium Chlamydia trachomatis. The type relevant to pregnancy (genital chlamydia) infects the cervix, urethra and sometimes the upper reproductive tract. It spreads through vaginal, anal or oral sex with an infected partner.

Worldwide, the WHO estimates roughly 4% of women aged 15–49 have chlamydia, with wide regional variation. In India, studies from major antenatal and STI clinics put the prevalence among pregnant women at around 2–8%, and it frequently travels with other infections such as Gonorrhea in Women: Symptoms, Testing and Treatment in India, Trichomoniasis (Trich) in Indian Women: Symptoms, Tests, Cure and bacterial vaginosis.

Some groups carry higher risk: women under 25, those with a new or multiple sexual partners, women whose partner has an STI, and women presenting with abnormal discharge or signs of pelvic infection. But risk factors only tell part of the story — because chlamydia is so often silent, many infections are found only through routine testing.

For a deeper, non-pregnancy overview of the infection, see our full guide to chlamydia in Indian women.

• A change in vaginal discharge — often yellowish, cloudy or mucus-like, sometimes with a mild odour (unlike normal pregnancy discharge, which is usually clear or white and odourless)
• Burning or pain when you pass urine (dysuria), which can feel like a urinary infection
• Light bleeding after sex (post-coital bleeding) or unexpected spotting
• Pelvic discomfort or lower abdominal pain
• Pain during sex (dyspareunia)

Untreated chlamydia is linked to several pregnancy complications. The evidence comes from cohort studies and treatment trials reviewed by bodies such as ACOG, the CDC, RCOG, NICE and FOGSI.

The most important is preterm birth. Studies suggest women with untreated chlamydia have roughly 1.5–2 times the risk of delivering before 37 weeks, likely through low-grade inflammation of the membranes and reproductive tract. Early treatment reduces — though may not fully erase — this risk, which is why catching it early matters.

Chlamydia is also associated with premature rupture of membranes (your water breaking early), low birth weight, and chorioamnionitis (infection of the membranes and amniotic fluid). After delivery, it raises the chance of postpartum endometritis (a uterine infection), especially after a caesarean.

This matters a great deal in India, which has one of the highest preterm birth rates in the world (around 13%). NACO and FOGSI both highlight chlamydia screening and treatment as a practical, cost-effective way to improve newborn outcomes — even in resource-limited clinics.

If a mother has untreated chlamydia at delivery, the baby can pick it up while passing through the birth canal — this happens in roughly half of such vaginal births. The two main newborn problems are:

Neonatal conjunctivitis (eye infection). This is the most common, appearing in about 30–50% of exposed babies, usually 5–14 days after birth — later than gonococcal eye infection. Signs are sticky discharge, redness and swollen eyelids, often in both eyes. It needs oral antibiotics (azithromycin or erythromycin), not just eye drops, because the bacteria also colonise the nose and throat. If your newborn develops persistent eye discharge or a sticky eye, have it checked rather than assuming it's a blocked tear duct.

Neonatal pneumonia. Less common (about 5–20% of exposed babies) but more serious, this usually develops between 1 and 3 months of age, with a staccato cough, fast breathing, congestion and poor feeding (fever is often mild or absent). It's treated with oral antibiotics, and most babies recover fully.

Importantly, a caesarean does not reliably prevent transmission — especially if the waters have already broken — and is not recommended as a way to protect the baby. Routine newborn eye ointment (commonly erythromycin or tetracycline in India) is aimed mainly at preventing the faster, more sight-threatening gonococcal eye infection and works poorly against chlamydia. The single best protection is treating the infection in the mother during pregnancy.

• Best timing: at the first antenatal visit, and again in the third trimester for women treated earlier or at ongoing risk.
• Self-collected vaginal swabs are validated and as accurate as clinician-collected ones — useful if you're uncomfortable with an internal exam.
• A test-of-cure 3–4 weeks after treatment is specifically recommended in pregnancy (unlike routine non-pregnancy chlamydia care).
• Testing is free and confidential at NACO-designated STI/RTI clinics — see our guide to STI testing options and costs in India.

• Use condoms consistently and correctly to prevent new infections during and after pregnancy, especially if you're not in a mutually monogamous relationship.
• Get a full STI screen at diagnosis — about 25–50% of women with chlamydia also have another STI, so testing for gonorrhoea, trichomoniasis, Syphilis in Women: Stages, Tests and Penicillin Cure, HIV and hepatitis B is standard.
• If you were treated early in pregnancy, expect a repeat test in the third trimester to catch any new or recurrent infection before delivery.

The best protection is to prevent or detect chlamydia early. If you're planning a pregnancy, an STI check is a valuable part of preconception planning — it lets any infection be cleared before you conceive. If pregnancy comes as a surprise, first-trimester antenatal screening does the same job.

Day to day, the proven measures are consistent condom use, mutual monogamy with an uninfected partner, limiting partner numbers, and regular STI testing if you're sexually active. India's public-health system supports this through NACO and state AIDS control societies, with designated STI/RTI clinics offering free or low-cost testing and treatment. Antenatal STI care is woven into the Reproductive and Child Health programme, including the free monthly check-ups under Pradhan Mantri Surakshit Matritva Abhiyan (PMSMA).

Why push so hard on detection? Because the long-term cost of untreated chlamydia is steep. PID following chlamydia carries roughly a 15–30% risk of tubal infertility, raises ectopic pregnancy risk many-fold, and leaves about 1 in 5 affected women with chronic pelvic pain. In a context where fertility carries deep personal and social weight, finding and treating chlamydia in pregnancy is one of the highest-value things antenatal care can do. (And if any discharge or pelvic symptom is worrying you now, our guide to normal vs abnormal discharge in pregnancy can help you tell what needs a doctor.)

• Abnormal vaginal discharge, bleeding after sex, or burning when you urinate
• Pelvic or lower abdominal pain, or pain during sex
• A known STI in you or your partner, or a new partner during pregnancy
• Signs of preterm labour: regular tightening or cramping before 37 weeks
• A gush or steady leak of fluid (possible early rupture of membranes), or fever with foul-smelling discharge — seek urgent care
• After birth: your newborn develops eye discharge, redness or swelling, or (in the first months) a persistent cough, fast breathing or poor feeding

• WHO — Chlamydia (fact sheet)
• CDC — STI Treatment Guidelines: Chlamydial Infections
• NACO — National Guidelines for the Management of Sexually Transmitted Infections / RTIs
• ACOG — Sexually Transmitted Infections (pregnancy guidance)
• NICE CKS — Chlamydia (uncomplicated genital): management