Subfertility and risk of spontaneous abortion

Objectives. The purpose of this study was to assess the association between subfertility and spontaneous abortion. Methods. A total of 1572 women in New York and Vermont reported 3269 pregnancies between 1980 and 1990 and were able to provide an estimate of the waiting time to conception for 2967. Subfertility was defined as a delay of 1 year or more before a recognized conception was achieved. Rates of spontaneous abortion were determined among women with and without subfertility, and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated via multiple logistic regression. Results. Spontaneous abortion rates were 23.0% in pregnancies preceded by subfertility and 14.0% in pregnancies without impaired fertility (adjusted OR = 1.71. 95% CI = 1.26, 2.94). The attributable risk of spontaneous abortion associated with subfertility was 6.2%. Conclusions. Subfertile women evidence an increased number of spontaneous abortions.