Effects of intra-amniotic and maternal intramuscular injection of glucocorticoid on fetal lung maturity and blood glucose level in women with gestational diabetes mellitus

Objective To compare the effects of intra-amniotic and maternal intramuscular injection of glucocorticoid on fetal lung maturity and blood glucose level in gestational diabetes mellitus (GDM) and pre-gestational diabetes mellitus (PGDM). Methods A total of 60 GDM and PGDM women, whose blood glucose control was inadequate and who needed glucocorticoid treatment for fetal lung maturity, were selected in Peking University First Hospital from January 2013 to April 2015. They received intramuscular (29 women) or intra-amniotic (31 women) injection of dexamethasone. Amniotic fluid samples were collected from the two groups during cesarean section for the oscillation test and for determining the surfactant protein-A level. Outcome of the neonates was followed up. Their blood glucose levels and after treatment, fetal lung maturity and neonatal outcomes were analyzed and compared. Two-samplettest, sum-rank,Chi-square and Fisher exact tests were used for statistical analysis. Results (1) Before treatment, the intra-amniotic injection group had a higher preprandial blood glucose level than intramuscular injection group [(5.8±0.6) vs (5.3±0.7) mmol/L,t=-2.730,P=0.008]. On the first day after treatment, preprandial blood glucose level in intramuscular injection group was (6.5±0.8) mmol/L, and elevated by (1.2±0.9) mmol/L compared with before treatment; preprandial blood glucose in intra-amniotic injection group was (6.7±1.3) mmol/L, and increased by (1.1±1.2) mmol/L. There was no statistical difference in the increment of preprandial blood glucose between the two groups (t=0.548,P=0.586). On the second day after treatment, preprandial blood glucose in intramuscular injection group was higher than before treatment (t=9.070,P=0.000), while preprandial blood glucose in intra-amniotic injection group restored to the pre-treatment level (t=0.516,P=0.612), and preprandial blood glucose in intramuscular injection group was higher than in intra-amniotic injection group [(6.9±0.9) vs (5.6±0.8) mmol/L,t=4.676,P=0.000]. On the third day after treatment, preprandial blood glucose in intramuscular injection group decreased to (5.7±0.4) mmol/L, but was still higher than before treatment (t=3.000,P=0.034), while there were no differences in intra-amniotic injection group compared with the level before treatment [(5.9±2.0) vs (5.8±0.6) mmol/L,t=-0.226,P=0.826]. The preprandial and postprandial blood glucose showed a similar trend of change in the two groups. (2) There were no differences in the mature rate [86% (24/28) vs 88% (23/26), Fisher exact test] by the oscillation test and surfactant protein-A level [(1 489.1±669.3) vs (1 495.2±535.7)μg/L,t=-0.037], the gender ratio, birth weight, and incidences of macrosomia, neonatal asphyxia, hypoglycemia and hyperbilirubinemia between intramuscular injection group and intra-amniotic injection group (allP>0.05). No neonatal respiration distress syndrome occurred in the two groups. Conclusions Intra-amniotic injection and intramuscular injection of dexamethasone have the same effects on elevating maternal blood glucose level, but the duration of the effects of intra-amniotic injection is shorter. Key words: Fetal organ maturity; Lung; Glucocorticoids; Injections; Injections, intramuscular; Diabetes, gestational; Blood glucose