Though recommended for pregnant women at risk of
preterm birth to improve perinatal outcomes, antenatal
corticosteroid (ACS) treatment can cause maternal
hyperglycemia, especially in cases of
glucose intolerance. A standardized protocol for preventing
hyperglycemia during ACS treatment remains to be established. We herein retrospectively investigated the time-dependent changes in
insulin dose required for maternal
glycemic control during ACS treatment in
gestational diabetes (GDM). Twelve singleton pregnant women with GDM who received 12 mg of
betamethasone intramuscularly twice 24 hours apart were included in this analysis. Of those, eight also received
ritodrine hydrochloride for
preterm labor. The
blood glucose levels were maintained at 70-120 mg/dL with continuous
intravenous infusion of
insulin and nothing by mouth for 48 hours after the first
betamethasone administration. After the first dose of
betamethasone, the
insulin dosage needed for
glycemic control gradually increased and reached a maximum (6.6 ± 5.8 units/hr)
at 10 hours, then, decreased to 4.1 ± 1.5 units/hr at 24 hours. Similar changes in the
insulin requirement were found after the second
betamethasone dose (the maximum
insulin dosage: 5.5 ± 1.6 units/hr at 9 hours following the second administration). Women treated with
ritodrine hydrochloride needed more
insulin, than those without
ritodrine hydrochloride treatment (130.8 ± 15.0 vs. 76.8 ± 15.2 units/day, respectively, p < 0.05). Our data indicated that the requirement for
insulin is highest 9-10 hours after each dose of
betamethasone. When GDM is treated with ACS, levels of
blood glucose should be carefully monitored, especially in patients treated with
ritodrine hydrochloride.