[Perinatal aspects of 520 twin deliveries between 1965-87 at the Ulm University Gynecologic Clinic].

1. Birth induction in twin pregnancies was substantially reduced to 6% in last few years (1984-87) as opposed to 21% between 1975 and 1980. 2. Premature rupture of the membrane increased in the last years. At a rate of 33% is occurred nearly twice as often as with singletons (18%). A waiting policy increasingly adopted in such cases resulted in 21% of the twin group and 9% of the singleton group being born as late as 48 hours and beyond after membrane rupture. 3. The frequency of Caesarean sections performed in twin pregnancies rose dramatically over the last 22 years: 16%, 36%, 43%, 45%. With singletons, the tendency is reverse: 6%, 22%, 15%, 9%. One of the reasons why Caesarean sections are so markedly on the increase is that the frequency of immaturity in twins is steadily rising. In the past two decades the percentage of second twins less than 2500 grams birth weight rose from 35% to 71%. 4. Labour duration exceeding 12 hours increased from 8% to 21%. The same applies to the expulsion time of the first twin which rose on average from 10 to 21 minutes. 5. Manual delivery of the placenta remained at a steady rate of 25%, compared to 10% after singleton deliveries. 6. Hospitalization time exceeding two weeks decreased in the study period from 33% to 5%. 7. The perinatal mortality rate of twins could be halved in the period from 1965 to 1987, to less than 4%. The frequency of Caesarean sections, on the other hand, increased threefold to 48% now.(ABSTRACT TRUNCATED AT 250 WORDS)