Association between familial autoimmune diseases and recurrent spontaneous abortions.

Problem: To examine the aggregation of autoimmune disease in the families of women experiencing recurrent spontaneous abortions.
Method: The 95 participants in this case-control study were recruited from Magee Womens Hospital, Pittsburgh, Pennsylvania from June 1988 to May 1991. The women having recurrent spontaneous abortions (N = 45) reported at least three early fetal losses, and the controls (N = 50) reported a minimum of three pregnancies with at least two live births and no more than one induced or involuntary pregnancy loss. Data from the participants and from their first-degree and second-degree relatives were obtained by questionnaire and verified by a repeated interview, if necessary.
Results: The prevalence of arthritis, thyroid disease, and diabetes mellitus was increased among the relatives of women having recurrent spontaneous abortions compared to normally fertile couples. Several autoimmune diseases occurred concurrently in family members of patients, but not in the family members of normally fertile couples.
Conclusions: Autoimmune diseases occur more frequently in the families of women who have experienced recurrent spontaneous abortions. Both types of diseases involve genes in the class II region of the major histocompatibility complex.