SEASONAL PATTERNS IN TUBAL PREGNANCY

An investigation of possible seasonal patterns in ectopic tubal pregna ncies was conducted. The computer data utilized were based on all ecto pic pregnancies, abortions and deliveries (total pregnancies) recorded in the Department of Obstetrics and Gynecology at the Chaim Sheba Med ical Center, Israel, between the years 1986 and 1989. Composite monthl y cohorts of ectopic tubal pregnancies and total pregnancies were cons tructed for each month of the year, and the probability of an ectopic pregnancy was estimated. A statistically significant increase in the p robability of conception rate resulted in ectopic pregnancies which oc curred during winter and spring, especially in January to June. The pr obability of ectopic tubal pregnancies was low (0.50%) in September an d high (1.81-1.42%) in December to January. When we studied primigravi dae, the same seasonal pattern was observed. The findings of our study suggest, for the first time, that there is an association between met eorological and environmental factors, and ectopic pregnancies. These factors should be considered in the epidemiology of ectopic tubal preg nancies.