Can Chlamydia Infection Cause Miscarriage?

Women With Untreated Chlamydia Have a Higher Risk of Pregnancy Problems

pregnant women in waiting room
Blend Images - Jose Luis Pelaez Inc/Getty Images

A chlamydia diagnosis might have you wondering: Does chlamydia cause miscarriage?

Chlamydia is one of the most common sexually transmitted diseases (STD) out there, with as many as 3 to 4 million new infections each year. But what are the risks of chlamydia infection during pregnancy?

Does Chlamydia Cause Miscarriage?

There is some evidence that chlamydia infection could play a role in miscarriages: 

  • In 2007, researchers uncovered a possible biological mechanism by which Chlamydia trachomatosis, the strain that causes the STD known as chlamydia, could cause a miscarriage by attacking early pregnancy cells, although more research is needed to flesh out the concept.
  • And in a 2008 review, researchers concluded that several microorganisms similar to chlamydia may be related to miscarriage. 
  • Then, in 2011, a Swiss study of blood, vaginal fluid and placenta samples from women found a higher rate of signs of chlamydia in women who miscarried than in women who carried their babies to term. This supports the idea that there is an increased risk of miscarriage in women who are infected with chlamydia.

Other Problems Caused by Chlamydia 

To add to that, according to the Centers for Disease Control and Prevention (CDC), untreated chlamydia can increase the risk of:

  • preterm delivery
  • premature rupture of the membranes surrounding the baby in the uterus
  • low birth weight 

Your baby may also become infected with chlamydia during birth if you're not being treated for it, and this can cause eye and lung infections.

Having had a chlamydia infection in the past may also double the risk of ectopic pregnancy, in part by increasing the risk of pelvic inflammatory disease.

Unfortunately, an ectopic pregnancy is not a viable pregnancy. A prior infection may also cause fertility problems. 

Chlamydia During Pregnancy

Not surprisingly, this evidence suggests that it is a good idea to protect yourself from chlamydia before and during pregnancy, and to have it promptly treated if you do acquire it. Although researchers do not fully understand the relationship between chlamydia and miscarriage, getting treatment is always a good idea if you have any STD. 

You should be tested for chlamydia at your first prenatal visit and again in your third trimester if you're considered to be at high risk for the STD. Testing is done on a urine sample or a sample of vaginal fluid taken with a swab. 

Most women don't have symptoms with chlamydia. If you're pregnant and do have symptoms, you may experience:

  • abnormal vaginal discharge
  • bleeding after sex
  • itching/burning with urination

If you feel you have symptoms of chlamydia or that you may be at risk, promptly talk to your doctor about testing and treatment.

Fortunately, treatment is very simple. During pregnancy, you can be safely treated for chlamydia with a single dose of an oral antibiotic called azithromycin . After that, you should be tested to make sure the infection has cleared up within three to four weeks. You may also be tested for chlamydia again later in your pregnancy, just to be sure you haven't reacquired it. 


STDs during Pregnancy - CDC Fact Sheet. Centers for Disease Control and Prevention. February 3, 2016.

Chlamydial Infections. Centers for Disease Control and Prevention. June 4, 2015.

Baud, D., Goy, G., Jaton, K., et al. (2011). Role of Chlamydia trachomatis in Miscarriage. Emerging Infectious Diseases.

Bakken, I.J., Skjeldestad, F.E. and Nordbo, S.A. (2007). Chlamydia trachomatis infections increase the risk for ectopic pregnancy: a population-based, nested case-control study. Sexually Transmitted Diseases 

Baud, D., Regan, L. and Greub, G. (2008). Emerging role of Chlamydia and Chlamydia-like organisms in adverse pregnancy outcomes. Current Opinions in Infectious Diseases.

University of Wisconsin - Milwaukee, "Rogue bacteria involved in both heart disease and infertility." EurekAlert. Nov 19, 2007.

Continue Reading