Prospective delivery of reliably dated term infants of diabetic mothers without determination of fetal lung maturity: comparison to historical control.

OBJECTIVE

To determine whether omitting fetal lung maturity (FLM) testing prior to delivery in term pregnancies complicated by gestational (GDM) and pregestational diabetes mellitus would increase the risk of neonatal respiratory distress syndrome (RDS).

METHODS

In a 2-year study (1990-91), 1,457 pregnant women with accurately dated pregnancies were enrolled after 37 completed weeks and prospectively followed through delivery without FLM testing (study group). The prevalence of RDS and other neonatal outcomes was compared with a historical control group (n = 713, 1988-89) who had undergone determination of lecithin/sphingomyclin ratio prior to delivery at term. Logistic regression analysis was performed to determine independent predictors of RDS.

RESULTS

The study group compared to the control group had less severe diabetes: diet-controlled GDM, 35% vs. 18%, respectively; insulin-requiring GDM, 42% vs. 42%, respectively; undiagnosed type-2 diabetes, 14% vs. 31%, respectively; and pre-existing diabetes, 9.6% vs. 8.8%, respectively, p < 0.001. RDS rates in the study group (0.8%) and control group (1.0%) were not significantly different, nor were rates of resuscitation at delivery, neonatal intensive care admission or hospitalization days. Logistic regression analysis found only Cesarean delivery to be independently predictive (adjusted OR 2.21, 95% CI 2.04-2.27) of RDS. Non-predictive variables included FLM testing, diabetic classification, insulin use, poor third-trimester glycemic control, chronic hypertension, pre-eclampsia, labor, neonatal gender, gestational age or large-for-gestational-age fetuses.

CONCLUSIONS

Routine FLM testing did not change the RDS prevalence in reliably dated, term infants of diabetic mothers and should be abandoned. Delivery by Cesarean section was associated with increased RDS.