The objective of this study was to investigate temporal changes in the reported rates of spontaneous abortion associated with Type 1 diabetes. Individuals from the Children's Hospital of Pittsburgh Type 1 Diabetes Registry for 1950-1964 (n=495) completed a self-report reproductive history questionnaire in 1981 that was updated in 1990. Data from both surveys, which proved to be valid and reliable, were utilized for this report. More spontaneous abortions (26.8 vs. 7.7%, P<0.001), stillbirths (4.7 vs. 1.2%, P<0.001) and induced abortions (7.0 vs. 0.9%, P<0.001) were reported for Type 1 diabetic women than for the non-diabetic partners of Type 1 diabetic men. A significant temporal decline in the rates of spontaneous abortion for Type 1 diabetic women was observed (< or = 1969: 26.4%; 1970-1979: 31.0%; 1980-1989: 15.7%; P<0.05). No differences were apparent for the non-diabetic partners of Type 1 diabetic men (< or = 1969: 4.2%; 1970-1979: 9.5%; 1980-1989: 5.7%; P>0.05). Temporal changes in medical care for women with diabetes (i.e. self-monitoring of glycemic control) may have contributed to a recent reduction in spontaneous abortions associated with maternal Type 1 diabetes.