Comparison of umbilical artery Doppler and non-stress test in assessment of fetal well-being in gestational diabetes mellitus: A prospective cohort study

Background Gestational diabetes mellitus (GDM) is one of the most common medical complications of pregnancy and is related to poor perinatal outcomes. Reduction of neonatal complications of GDM is feasible by assessment of fetal well-being. Both fetal Doppler and NST are used for the screening of high-risk pregnancies. Objective We aimed to compare the non-stress test (NST) and umbilical artery (UA) Doppler assessments for evaluation of the adverse perinatal outcomes in GDM. Methods We conducted a prospective cohort study on 50 pregnant women with GDM in Jame Zanan Hospital, Tehran, Iran, from Oct 2014 to Sep 2015. A convenient sampling method was used for patient recruitment. Inclusion criteria were women with GDM, singleton pregnancies, and gestational age>32 weeks who had neither medical conditions nor fetal anomalies. Adverse perinatal outcomes were defined as Apgar scores at 1-min and 5-min <7, hypoglycemia (blood glucose <45 mg/dl), neonatal acidosis (PH<7.2), hypocalcemia (Ca<8 mg/dl), admission to the NICU for more than 24 hours, and perinatal death. Statistical analyses were performed with SPSS version 16 using Chi-square, Fisher's exact test, and independent-samples t-test. The significance level was considered at 0.05. Results Totally, 22% and 12% of women had an abnormal UA Doppler and a non-reactive NST respectively. Poor outcomes were detected in 13 women. The most frequent poor outcomes were hypoglycemia (n=9), Apgar 1-min <7 (n=8), neonate admitted in NICU (n=6), and respiratory distress syndrome (n=6). Poor outcome was more prevalent in women with non-reactive NST (p<0.001), abnormal UA Doppler (p=0.033), and those with infant birth weight >4000 gram (p=0.033). Sensitivity and specificity of the NST in predicting different poor outcomes were 76.9% and 97.3% respectively. Sensitivity and specificity of UA Doppler in predicting different poor outcomes were 30.8% and 94.6% respectively. Conclusion NST is a better predictor of adverse perinatal outcomes in GDM patients.