NATURAL INTERPREGNANCY INTERVALS OF FERTILE COUPLES - A LONGITUDINAL SURVEY OF GRAND GRAND MULTIPAROUS WOMEN

Objective: To characterize the natural fecundity of grand grand multip arous women (greater than or equal to 10 deliveries) in relation to ag e, number of pregnancies, body mass index, and chronic diseases. Desig n: A retrospective longitudinal analysis of interpregnancy intervals o f married couples who had never used any kind of contraception. Patien ts, Participants: The interpregnancy intervals (months from delivery o r spontaneous abortion to the next conception) of 96 grand grand multi parous women with a total of 1,327 pregnancies were evaluated from the first to the latest pregnancy (14 +/- 1.7; mean +/- SD). Because of t he lack of reliable data on conception times, 109 pregnancies had to b e excluded. The number of interpregnancy intervals remaining for evalu ation was thus 1,218. Results: The mean interpregnancy intervals in th e material of 1,218 pregnancies was 8.5 +/- 4.9 months, being signific antly shorter after an abortion (5.3 +/- 4.8 months) or stillbirth (6. 0 +/- 4.7 months) than after a delivery (8.9 +/- 5.6 months). The inte rpregnancy interval was significantly longer in women over 30 years of age than in the younger women, approximately 7 months in the latter a nd exceeding 10 months around the age of 40 years. Body mass index and chronic medical illness did not influence the interpregnancy interval s. The incidence of spontaneous abortions increased after the age of 3 0 years. It was 6% until 30 years, 10% between 31 and 35 years, and 25 % after 40 years. Conclusions: In this retrospective longitudinal revi ew, the reproductive capacity of fertile couples remains rather sound until premenopausal age. The data suggest that a woman's delivery capa city could be 25 births between 16 and 45 years of age.