Betamethasone alteration of the one-hour glucose challenge test in pregnancy

To determine if betamethasone administration alters the one-hour (50-g) glucose challenge test (GCT) and, if so, to determine the duration of this effect.

Pregnant women with singleton gestations eligible to receive antenatal betamethasone (24-34 weeks) with no evidence of infection, diabetes mellitus, hepatic or pancreatic disease, betamimetic therapy or prolonged steroid use were invited to participate. Betamethasone (12 mg) was administered intramuscularly upon admission and repeated in 24 hours. After an 8-hour fast, a 50-g GCT was administered 24 hours (day 1) and 72 hours (day 3) after the second betamethasone injection. Plasma glucose samples were drawn one hour after the glucose challenge. Statistical analysis utilized the McNemar exact test.

Seven patients, all with normal GCTs 7-10 days outside the study period, were enrolled. Six had abnormal GCT results on day 1 (P = .03). Three had abnormal results on day 3.

Betamethasone administration results in abnormal one-hour GCTs in pregnant women.