Infectious processes: an infrequent cause of first trimester spontaneous abortions

A systematic assessment of infections beginning early in pregnancy is necessary to determine the true role of infections in pregnancy loss, given that infections could readily arise only after fetal demise. To this end, we have prospectively determined the frequency of infections in pregnant women who were subjects in a multi-centre US study. Insulin-dependent diabetic subjects and controlled subjects were recruited either before conception (86%) or at the latest within 21 days of conception (14%). We collected data prospectively on all important risk factors and potential confounding variables, seeing 386 diabetic subjects weekly and 432 control subjects every other week during the first trimester. At each visit we inquired about untoward events and explicitly about fever or infections. We found no clinical evidence that infection occurred more often in the 116 subjects experiencing pregnancy loss as compared to the 702 having successful pregnancies. This held both for the 2 week interval in which a given loss was recognized clinically as well as in the prior 2 week interval. Similar findings were not only observed for both the control as well as diabetic subjects but also when data were stratified by genital infection only or by systemic infection only. Our prospective data suggest that the attributable risk of infection in first trimester spontaneous abortion is small.