PROSPECTIVE-STUDY OF SPONTANEOUS FETAL LOSSES AFTER INDUCED ABORTIONS

The incidence of spontaneous abortions was observed among 31,917 women followed from their first prenatal visit. Life-table analysis showed that losses in the first trimester were not significantly affected by previous induced abortions, nor was any change in the risk of second-trimester losses detected among the 1493 parous women who reported having had induced abortions after childbirth. There was, however, an increase in the incidence of midtrimester losses among the 2019 nulliparous women with previous induced abortions; the age-adjusted rate of loss was 59.9 per 100,000 women at risk per day, as compared with 24.2 among the 12,042 control nulliparous women (P<0.001). The relative risk increased with the number of previous induced abortions and was not explained by the distribution of demographic and social variables. The risk decreased from 3.27 (95 per cent confidence limits, 1.72 to 6.23) after abortions induced before 1973, mainly by dilation and curettage, to 1.42 (0.76 to 2.65) after those done since 1973, when the more gentle technic of cervical dilation by use of laminaria was introduced. These findings indicate that there is little or no risk of spontaneous abortions after induced abortions when performed by current technics. (N Engl J Med 301:677–681, 1979) WHETHER induced abortion increases the risk of spontaneous miscarriages in future pregnancies is a question that has not yet been answered.1 Many gynecologists argue that cervical incompetence leading to midtrimester miscarriage or preterm birth may be a sequel of cervical laceration; some also believe that early miscarriage may follow infections and excessive curettage of the endometrium. Much previous research is of doubtful validity, having been done in countries where practices of abortion, obstetrics and contraception are quite different from those in the United States. Inadequate numbers, a retrospective study design and failure to standardize for demographic differences between women having. © 1979, Massachusetts Medical Society. All rights reserved.