Antepartum fetal surveillance in patients with diabetes: when to start?

Although antepartum fetal well-being testing is an accepted practice in the management of diabetic patients, there are few data suggesting when to start. Our goal was to examine when testing should be started in the pregnant diabetic woman.

Antepartum test results and patient histories were prospectively collected on all diabetic pregnancies from January 1981 through December 1991. The data were retrospectively analyzed for when fetal compromise became evident. Fetal compromise was defined as stillbirth, first positive contraction stress test, or intervention because of an abnormal antepartum fetal test result.

Six hundred fourteen patients were enrolled in the study. There were three stillbirths, 45 (7.4%) patients had at least one positive contraction stress test, and 71 (11.6%) patients were delivered because of an abnormal fetal test result. Those with early compromise (< or = 34 weeks' gestation) could not be identified solely by diabetic class. The majority of patients (73%) requiring early intervention because of an abnormal test were class R or F diabetic patients with a growth-retarded fetus or were patients who had a concomitant diagnosis of hypertension.

Class R or F diabetic patients or diabetic patients with a growth-retarded fetus or a concomitant diagnosis of hypertension may require testing to be started as early as 26 weeks' gestation. Otherwise, testing may be safely delayed until 32 weeks' gestation.