Mycoplasma genitalium (Mg), a sexually transmitted bacterium, may cause female reproductive morbidities, including pelvic inflammatory disease (PID). As the clinical and risk profile of women with Mg is not well understood, we examined the characteristics of Mg among women. Data from 586 women with clinically suspected PID enrolled in the PID Evaluation and Clinical Health Study were analyzed. Clinical, demographic, sexual and behavioral characteristics were compared between women positive and negative for Mg in the cervix and/or endometrium by polymerase chain reaction (PCR), and between Mg positive and Chlamydia trachomatis (Ct) and/or Neisseria gonorrhoeae (Gc) (Ct/Gc) positive women. Mg positive women had similar clinical characteristics as women without Mg and as women with Ct. Compared to women with Gc, women with Mg had lower pelvic pain scores (p=0.01), and were less likely to have cervicitis (p=0.001), erythrocyte sedimentation rate >15mm/hr (p=0.002), white blood cell count >10,000mm3 (p=0.02), and oral temperature >38.3°C (p=0.08). Age <25 years (AOR 2.7, 95% CI 1.5-5.2), douching (AOR 2.3, 95% CI 1.3-4.1), and smoking (AOR 1.8, 95% CI 1.0-3.2) were associated with Mg. The demographic, sexual and behavioral characteristics were similar between Mg positive women and Ct/Gc positive women.Since Mg is associated with PID, Mg may affect pregnancy, yet the consequences of prenatal Mg are unknown. Therefore, we next conducted a nested case-control study to examine the relationship between Mg and spontaneous abortion (SAB) among women enrolled in the Early Pregnancy Study, a study of violence and SAB among pregnant women presenting at an Emergency Department. Mg was measured by PCR in urine from 82 women who experienced a SAB and 134 control women. Characteristics of cases and controls were compared and the relationship between Mg and SAB was evaluated. Mg was not associated with SAB but was associated with nulliparity (AOR 3.4, 95% CI, 1.0-11.6), self-reported difficulty conceiving (AOR 4.8, 95% CI 0.9-25.7), and history of PID (AOR 3.9, 95% CI 0.9-16.1) and Ct (AOR 3.0, 95% CI 0.8-10.5).This dissertation yields significant public health findings by describing the clinical picture of Mg-PID, identifying women at risk, and examining the consequences of prenatal Mg
