Impacts of tocolytics on maternal and neonatal glucose levels in women with gestational diabetes mellitus

We studied the impacts of tocolytic agents on maternal and neonatal blood glucose levels in women with gestational diabetes mellitus (GDM) who were admitted for preterm labor. This multi-center, retrospective cohort study included women with GDM who were admitted for preterm labor from twelve hospitals in South Korea. We excluded women with multiple pregnancies, women with type 2 DM, and women who received multiple types of tocolytics. The patients were divided according to the types of tocolytics; ritodrine, atosiban, and nifedipine group. We collected baseline maternal characteristics, pregnancy outcomes, maternal glucose levels during hospitalization, and neonatal glucose levels after birth. A multivariable logistic regression analysis was performed to determine associations between abnormal maternal and neonatal abnormal glucose levels and the types of tocolytics. A total of 134 women were included: 54(40.3%), 46(34.3%), and 34 (25.4%) women received ritodrine, atosiban, and nifedipine, respectively. Fasting (FPG) (111.6, 108.0, and 89.5 mg/dL, p< 0.05) and 2-hour postprandial glucose (PPG) level (145.5, 146.9, and 116.5 mg/dL, p< 0.05) were significantly higher in ritodrine, atosiban group than those in nifedipine group. Even after adjusting for covariates including steroid use, gestational age at admission, pre-pregnancy body mass index, ritodrine and atosiban were 4.9 times and 3.7 times higher in risk of high FPG (≥95mg/dL) than nifedipine group, respectively (p< 0.05). Regarding neonatal hypoglycemia (< 50mg/dL), ritodrine and atosiban group has 5.2 and 3.9 times higher risks than nifedipine group, respectively (p< 0.05). There is an increased risk of maternal hyperglycemia and neonatal hypoglycemia in women with GDM using ritodrine and atosiban tocolytics for preterm labor compared to those using nifedipine.