Epidemiology of miscarriage and its relation to other reproductive events in Finland.

Objective: This study investigates the occurrence of miscarriages over the reproductive life span of women in a population-based study.

Study Design: A questionnaire was sent in 1994 to a random sample of 3000 Finnish women aged 18 to 44 years (73% response rate). Age-adjusted percentages of women having had miscarriages, and age- and other pregnancy event-adjusted odds ratios were calculated.

Results: Fifteen percent had at least 1 miscarriage. Miscarriages were more common in the moderately educated group and among women in health and social occupations, but there was no difference according to urbanism or health. By the age of 40 to 44 years, 90% of the women had been pregnant, and for only half had all pregnancies ended in a birth. The sequence of a miscarriage or miscarriages coming first and a birth or births coming later was more common than vice versa.

Conclusion: In this population-based study miscarriages appeared incidental. Further studies on social class distribution might reveal new clues regarding etiology.