Chlamydia is a common STD among both men and women. It can damage a woman’s reproductive system, making it difficult or impossible to get pregnant. Chlamydia can also cause a pregnancy to occur outside the womb or the infection to pass to your baby during delivery, causing an eye infection or pneumonia in your newborn. You should receive testing for chlamydia at your first prenatal visit. A positive result of Chlamydia trachomatis IgG indicates past, current, or chronic infection, while positive IgM antibodies indicate recent infection.