Clindamycin benefits pregnant women with BV: early treatment optimal

OB/GYN News,  Feb 15, 2004  by Damian McNamara

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PLAYA HERRADURA, COSTA RICA --Clindamycin use was associated with a significant reduction in the rates of late miscarriage and preterm birth in women with asymptomatic abnormal vaginal flora or bacterial vaginosis in a randomized, controlled study in a general obstetric population.

Second trimester loss occurred in 0.8% of 241 women with bacterial vaginosis (BV) treated with clindamycin, compared with 4.2% of 238 women given placebo. Other differences in pregnancy outcomes that were statistically significant using a univariate analysis included spontaneous preterm delivery (4.6% vs. 11%) and live term deliveries (91% vs. 83%), Dr. Phillip Hay said at a conference on vaginitis sponsored by Imedex.

Differences in induced preterm delivery (3.3% clindamycin group versus 1.3% placebo group) were not statistically significant. There was one intrauterine death in each group (0.4%). There were no serious adverse events in either group, said Dr. Hay, senior lecturer, department of genitourinary medicine, St. George's Hospital Medical School in London. Some of the results of the study were previously published (Lancet 361[9362]:983-88, 2003).

The greatest apparent benefit of treatment was for women with a Nugent's score of 10, signifying the worst B7 A subanalysis of only those women showed 89% had a live, term delivery versus 61% of women taking a placebo. The difference, however, was not statistically significant because of small numbers. Likewise, there was not enough statistical power in the cohort to show a statistically significant difference by ethnicity.

Previous findings suggest that timing of treatment is important to thwart second trimester loss, which is a more common experience in women with BV than in uninfected women.

"Second trimester miscarriage is more definitively associated with BV--1% of all pregnancies but 4% of BV pregnancies. We tried to treat as early as possible to prevent second trimester loss," he noted.

Dr. Hay and his colleagues attempted to retain placental tissue from all preterm births and a subset of term births. This subanalysis showed no difference in chorinamnionitis or inflammation between the two groups.

Optimum management of BV in pregnancy is still not known, Dr. Hay said. "Early treatment has to be one of the keys with this, at 12 to 13 weeks' gestation.'" In this study he and his colleagues started clindamycin 300 mg twice a day at an average of 15.8 weeks' gestation.

Metronidazole is standard for vaginal treatment, but it kills only about 50% of Gardnerella vaginalis, clindamycin kills up to 95% of G. vaginalis, but it also is more active against beneficial lactobacilli. Although the researchers studied clindamycin, other agents could also be effective, and "we are not recommending one drug over another at this point," Dr. Hay said.

Widespread treatment for BV in a low-risk obstetric population is probably not warranted, according to a review of studies from 1994 to 2001 that showed no significant improvement in preterm labor (Infect. Dis. Obstet. Gynecol. 11[2]:123-29, 2003). Dr. Hay concurred, and said screening and treatment should be targeted to high-risk women with a history of preterm labor or other risk factors for adverse pregnancy outcomes.

The researchers assessed posttreatment status in 231 women in each group. Only 6% of women in the clindamycin group still had BV, compared with 78% in the placebo group, a significant difference.

A longitudinal follow-up up to 36 weeks postdelivery showed there was less relapse in the clindamycin group.

DAMIAN MCNAMARA

Miami Bureau

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