Value of early glucose tolerance testing in women who had gestational diabetes in their previous pregnancy.

The patterns of glucose tolerance, clinical characteristics, and follow-up results of 1,027 pregnant women who had gestational diabetes diagnosed in their previous pregnancy, were analyzed. Glucose tolerance testing was performed before 24 weeks (mean 16.6 +/- 4.5 weeks) in 180 women (group 1); when the result was normal the test was repeated at 26-30 weeks' gestation. In this group the incidence of recurrent gestational diabetes was 49.4%, and early testing diagnosed 61.8% of cases. Group 2 consisted of 685 women in whom glucose tolerance was tested only at 26-30 weeks' gestation. In this group the incidence of recurrent gestational diabetes was 34.0%. Group 3 consisted of 162 women in whom glucose tolerance was not tested in the subsequent pregnancy. Perinatal mortality rates in Groups 1 to 3 were 2.2%, 0.6% and 3.1% respectively in the pregnancy subsequent to that in which gestational diabetes was first diagnosed. The risk of emerging diabetes mellitus on follow-up was greater in women in whom gestational diabetes was diagnosed early than in those diagnosed at the usual time (33.3% versus 12.5%, p < 0.05). Analysis of the 13 perinatal deaths in Groups 1-3 revealed 5 that were potentially avoidable; none of the 3 women with recurrent gestational diabetes in the early tested group who had perinatal deaths received insulin in their subsequent pregnancies. Although perinatal deaths are unavoidable in some high-risk pregnancies associated with gestational diabetes, this study suggests that early diagnosis of gestational diabetes may allow further reduction of perinatal mortality.(ABSTRACT TRUNCATED AT 250 WORDS)