Infertility and Early Pregnancy Loss

Abstract

The inability to achieve a recognized pregnancy may result from either failure of conception or implantation or an early postimplantation loss. Recently, a highly sensitive and specific assay for urinary human chorionic gonadotrophin (hCG) has enabled researchers to detect subclinical pregnancy losses. We used this assay to detect early pregnancy in a cohort of working women with and without fertility problems. One hundred forty eight female volunteers completed interviews, daily diaries an collected daily urine specimens for an average of seven months. The urine specimens were assayed for ovarian steroid hormones and hCG. Generalized estimating equations were used to estimate variance-corrected relative risks. There were 679 menstrual cycles at risk for pregnancy contributed by 124 of the women. Women with evidence of subfertility before or during the study period had a rate of early pregnancy loss of 70 percent compared to 21 percent of women without fertility problems (relative risk 2.63, 95%confidence interval 1.82-3.83. The risk of pregnancy loss associated with subfertility increased with age, and remained the same in women treated with clomiphene citrate. These results suggest that subfertile women have increased subclinical pregnancy losses regardless of fertility treatment, and the association between reduced fertility and advancing age may in part be related to early pregnancy loss.