Preterm birth has been linked to certain types of vaginal infections. The goal of this study is to determine if giving women pregnant between 13-20 weeks with an elavated vaginal pH(evidence of this type of infection)Oral Clindamycin(an antibiotic)will have a lower rate of preterm birth compared to women given a placebo(starch)

The primary study objective is to definitively test whether 300 mg oral clindamycin two times per day for 5-days administered at 13-20 weeks of gestation in women with a vaginal pH≥5 reduces the incidence of preterm delivery in Karnataka, India by at least 30%. The national incidence of gestation <37 weeks in India is 14.5%, was 18% in the study area in 2011 and was 20% among women with vaginal pH≥5 in the recently completed Jawaharlal Nehru Medical Collage (JNMC) hospital-based study of clindamycin to reduce preterm birth. Using a two tailed test, α=0.05, 1-β=80%, a 17.5% rate of prematurity in women with vaginal pH≥5, a 2.5% refusal and a 7.5% loss to follow-up, assuming 86% of women presenting for antenatal care are 13-20 weeks gestation and 1% otherwise ineligible, and a multiple comparisons adjustment, 1,726 women, half in the clindamycin and half in the placebo group, need to be enrolled to test the primary hypothesis. The effects of clindamycin on spontaneous preterm birth, miscarriage, low birthweight (LBW), neonatal mortality (NMR), maternal and neonatal complications through 42 days postpartum, the utility of vaginal pH≥5 to identify women at risk for preterm delivery and the costs of preterm birth prevented by oral clindamycin treatment and compliance with the 5-day treatment regimen will also be assessed. This will be the first investigation to test whether oral clindamycin prevents preterm birth in a community-based, developing country setting, where most global newborn deaths occur.

Inclusion Criteria:

• Women with a singleton Intrauterine pregnancy between 13-20 weeks
• Maternal age of 18 or older or if < 18 assent of the women's parent/guardian
• Vaginal PH > 5.0

Exclusion Criteria:

• Use of antibiotics within the 14 days prior to randomization
• Known sensitivity to antibiotics
• Uterine anomalies
• Major fetal anomalies
• Medical conditions that may result in iatrogenic prematurity(e.g.diabetes, Lupus, Hypertension)