Epidemiology of spontaneous abortions--the effect of previous abortions

J R Soc Health. 1987 Feb;107(1):31-3. doi: 10.1177/146642408710700114.

Abstract

PIP: 1050 women who became pregnant between September 1980 and September 1981 were followed from their 1st prenatal visit until the termination of their pregnancy to confirm the suspected effects of previous abortions, especially spontaneous abortions on subsequent pregnancies. The pregnant women were included sequentially in the study, and they comprised 550 referrals to the Oklahoma Memorial Hospital Women's Clinic and 500 inpatients of 5 private doctors' clinics. The latter also were selected sequentially. To control for some demographic variables, the 5 private doctors' clinics were those located in the middle class neighborhoods within the Oklahoma City metropolis; the 550 referrals were restricted to women referred from these private clinics. A detailed questionnaire was given to each patient at her 1st visit. The information gathered included medical and obstetric history and habits, number of previous induced and spontaneous abortions, ectopic pregnancies, stillbirths, and type of previous therapeutic abortion techniques. Spontaneous abortion was restricted to any losses prior to the 20th week of gestation; fetal wastage comprised all losses after 20 weeks of gestation plus stillbirths. Both fetal wastage and spontaneous abortions were grouped together as nonlive births (NLB). During the study period, 1050 women were followed until pregnancy termination, and 79% of these ended in full-term uncomplicated delivery. Spontaneous abortions accounted for 15.9%, and 5.1% were classified as fetal wastage. 208 patients reported having had spontaneous abortions; 109 reported having had previous therapeutic abortions. The odds that a non-live birth would occur among previous spontaneous aborters was over 2 times greater than the odds that a live-birth would occur. The history of previous therapeutic abortions and pregnancy outcome yielded a nonsignificant relative risk of 0.5. The relative risk of 1.7 for having a non-live birth given a previous spontaneous abortion suggests a positive association between previous spontaneous abortions and the incidence of non-live births. The relative risk of 2.7 for 3+ previous spontaneous abortions suggests an association, but the distribution of previous therapeutic abortions with pregnancy outcome failed to show any positive association.

MeSH terms

  • Abortion, Habitual / epidemiology*
  • Abortion, Induced*
  • Abortion, Spontaneous / epidemiology*
  • Female
  • Humans
  • Oklahoma
  • Pregnancy
  • Risk