Further study of the inhibition of premature labor by indomethacin. Part I.

Prematurity still remains one of the unsolved problems in obstetrics and is responsible for a majority of cases of perinatal morbidity and mortality. The use of indomethacin to stop uterine contractions and prevent premature delivery is based on the observation that indomethacin inhibits the release of prostaglandin which is assumed to play a role in the induction and continuation of labor. The effect of indomethacin as an antagonist to prostaglandin was evaluated in a series of 297 women in premature labor. The gestational age at admission varied between 24 and 34 weeks of pregnancy (120 primiparas and 177 multiparas). In 83% of cases there was complete cessation of labor for a period of 1 to 12 weeks, in 10% of cases from 2 to 7 days and in 7% there was no effect. The delay of premature labor for 2 to 7 days allowed the administration of betamethasone in an attempt to improve fetal lung maturity. The total daily dose needed for successful treatment was between 200-300 mg indomethacin. Dilation of cervix beyond 4 cm was associated with successful treatment in 58% compared to 90% if cervix was dilated 3 cm or less. In comparing women with intact membranes to women with ruptured, the success rate in suppressing premature labor was significant; 88% versus 53%. In 49 patients delivery was delayed 11-12 weeks. Fifty-one babies were born in spite of therapy, and of these 15 with birth weights of 700-1500 g suffered from respiratory distress syndrome and died. All the rest (36 premature and 246 mature infants) showed no ill effects related to the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)