Factors predisposing to and outcome of gestational diabetes.

Two hundred thirteen women with abnormal glucose tolerance tests (GTTs) were diagnosed over 9 years by a screening program involving the total antenatal population. Each subject was matched for age, parity, and ethnic group with a control. The gestational diabetics were subdivided into classes A1 or A2 based on the fasting plasma glucose value of their GTT: A1 when below 6.0 mmol/L (108 mg/dL) and A2 when 6.0 mmol/L (108 mg/dL) or higher. All received treatment with dietary advice and some with insulin. Birth weight was not related to maternal age or severity of diabetes, but was related to maternal obesity. However, neonatal morbidity indices such as admission to the special care baby unit for longer than 48 hours and polycythemia (hematocrit above 65%) were related significantly to the severity of the diabetes and not to maternal age or obesity.