Occurrence of other reproductive failures among women with recurrent spontaneous abortion.

We have previously reported an association between recurrent spontaneous abortion and ectopic pregnancy. We now report that not only ectopic pregnancy, but also other reproductive failures including hydatidiform moles, preterm births, and stillbirths are also associated with recurrent spontaneous abortion. The obstetrical histories of 455 women who had experienced two or more consecutive spontaneous abortions were studied for the occurrence of term births, preterm births, stillbirths, spontaneous abortions, ectopic pregnancies, and hydatidiform moles. The observed frequencies of these reproductive outcomes were compared with the expected frequencies of 920 term births, 80 preterm births, five stillbirths, 150 spontaneous abortions, 14.5 ectopic pregnancies and 0.5 molar pregnancies per 1,000 livebirths. The 455 women had experienced 1,968 pregnancies of which 184 were term births, 30 were preterm births, 16 were stillbirths, 1,669 were spontaneous abortions, 63 were ectopic pregnancies, and six were molar pregnancies. The ratio of observed to expected values was term births 0.1, preterm births 1.6, stillbirths 14.0, spontaneous abortion 6.6, ectopic pregnancy 2.6, and molar pregnancy 7.1. The gravid specific proportions of reproductive outcomes were constant suggesting comorbidity or common cause(s). The commonality that links these types of reproductive failure will provide insight into the mechanisms of reproductive wastage.