Erythromycin therapy for subclinical intrauterine infections in threatened preterm delivery--a preliminary report.

Evidence suggests that subclinical intrauterine infections which can be indicated by elevated maternal CRP-values may cause preterm labor and that Ureaplasma urealyticum might play a role in the pathogenesis of preterm delivery. Since these organisms are sensitive to erythromycin, 43 patients with threatened preterm labor were at the time of tocolysis treated with erythromycin, or placebo in a randomized study. Treatment with erythromycin resulted in a greater mean delay of delivery for 9 days than among the placebo-treated women. This effect is statistically significant in patients with intact membranes and cervical dilatation: in contrast to the placebo group these women achieved an increased delay of 23 days before delivering. Moreover, successful erythromycin treatment was significantly associated with the isolation of ureaplasmas from vaginal swabs. Our results emphasize that in cases with cervical dilatation, vaginal microorganisms, especially ureaplasmas, are more liely to ascend and might be involved in the initiation of preterm labor. Therefore, additional treatment with erythromycin was beneficial only in these women.