Adjunctive clindamycin therapy for preterm labor: Results of a double-blind, placebo-controlled trial

Abstract

A double-blind, placebo-controlled, randomized trial was conducted to evaluate the efficacy, safety, and tolerance of a course of clindamycin (administered for 3 days intravenously and 4 days orally) among hospitalized women with preterm labor at ≤34 weeks' gestation who were treated with tocolytics. One hundred three woman-perinate pairs were analyzed. Univariate analysis demonstrated that pregnancies were continued longer in women treated with clindamycin than in women who received placebo (clindamycin-treated group, 35 days; placebo-treated group, 25 days; p = 0.02). Survival analysis showed that pregnancy continued at least 35.5 days in 50% of clindamycin-treated women versus 20 days for control women (p = 0.03). Obstetric and microbiologic parameters associated with treatment outcomes were also sought. Women with bacterial vaginosis more often delivered preterm (p = 0.03; relative risk, 1.4; 95% confidence interval, 1.04 to 2.0). Among women with bacterial vaginosis, trends for increased duration of pregnancy (clindamycin-treated group, 36 days; placebo-treated group, 19 days), increased birth weight (clindamycin-treated group, 2634 gm; placebo-treated group, 2256 gm), and increased mean gestational age at delivery (clindamycin-treated group, 35 weeks; placebo-treated group, 34 weeks) were associated with clindamycin treatment. Women with either group B streptococcus, Chlamydia trachomatis, Trichomonas vaginalis, or Staphylococcus aureus were more likely to have preterm premature rupture of membranes (p = 0.01). Clindamycin treatment of these women reduced the incidence of preterm premature rupture of membranes to that of uninfected subjects. Stratification by gestational age at enrollment showed clindamycin treatment to be associated with an increased interval to delivery only among mothers enrolled before 33 weeks' gestation (clindamycin-treated group, 40 days; placebo-treated group, 28 days; p < 0.05). Treatment with clindamycin appeared safe and well tolerated, with benefits limited to women who were ≤32 weeks' gestation.