Early Pregnancy Screening for Women at High-Risk of GDM Results in Reduced Neonatal Morbidity and Similar Maternal Outcomes to Routine Screening

Abstract

The Australasian Diabetes in Pregnancy Society recommends screening high-risk women for gestational diabetes mellitus (GDM) before 24 weeks gestation, under the assumption that an earlier diagnosis and opportunity to achieve normoglycemia will minimize adverse outcomes. However, little evidence exists for this recommendation. The study objective was to compare the pregnancy outcomes of high-risk women diagnosed with GDM before 24 weeks gestation and routinely diagnosed women after 24 weeks gestation. A retrospective audit was conducted of all pregnancies diagnosed with GDM using International Association of Diabetes and Pregnancy Study Groups criteria over 12 months at a tertiary Australian hospital. Adverse perinatal outcomes were compared between “Early GDM” diagnosed before 24 weeks (n=133) and “Late GDM” diagnosed from 24 weeks (n=636). Early GDM had a significantly lower newborn composite outcome frequency (hypoglycemia, birth trauma, NICU/SCN admission, stillbirth, neonatal death, respiratory distress, and phototherapy) compared to Late GDM (20.3% vs. 30.0%, p=0.02). Primary cesarean, hypertensive disorders, postpartum hemorrhage, birthweight >90th percentile, macrosomia, and preterm birth frequencies were not significantly different between groups. Therefore, high-risk women diagnosed with GDM in early pregnancy were not more likely to have an adverse outcome compared to routinely diagnosed women. As they are a high-risk group, this may indicate a possible benefit to the early diagnosis of GDM.

Screening for Gestational Diabetes Mellitus in Early Pregnancy: What Is the Evidence?

“…An Australian study demonstrated also that early diagnosis and intervention had no effect on pregnancy outcomes [ 21 ]. This was confirmed by a recent Australian study showing no differences in pregnancy outcomes between early-onset GDM and late-onset GDM [ 30 ].…”

“…In general, most studies show that women with early GDM are at high risk for adverse pregnancy outcomes but treatment of GDM early in pregnancy compared to later in pregnancy does not always translate into improved outcomes. Seven studies reported an improved pregnancy outcome by treatment of early-onset GDM [ 7 , 9 , 10 , 29 , 30 , 31 , 34 ]. Barahona et al [ 9 ] showed that diagnosing GDM early in pregnancy is a predictor of adverse maternal and neonatal outcomes, such as pregnancy-induced hypertension, insulin treatment during pregnancy, preterm birth, hyperbilirubinemia and perinatal mortality.…”

“…However, five studies described no beneficial effect of early diagnosing or treatment of GDM on maternal or neonatal outcomes [ 15 , 20 , 22 , 25 , 30 ]. Both Alluni et al [ 15 ] and Bianchi et al [ 25 ] showed that patients diagnosed and treated for early-onset GDM were more prone to be insulin-treated during pregnancy but showed no differences in neonatal outcomes such as small-for-gestational age (SGA) infants, cesarean sections, macrosomia, and LGA.…”

Metabolomic Biomarkers in Gestational Diabetes Mellitus: A Review of the Evidence

“…There is some evidence in support of a reduction in neonatal morbidity by achieving normoglycemia earlier in pregnancy with the adoption of early screening. For most healthy women, there is a lack of evidence linking early screening to improvements in neonatal outcomes [ 49 ]. However, high risk women are more likely to benefit from an early diagnosis of GDM.…”

“…However, high risk women are more likely to benefit from an early diagnosis of GDM. In a retrospective cohort study performed by Clarke et al [ 49 ], women with an “early GDM” diagnosis (at an average of 17 weeks’ gestation) had better composite neonatal outcomes than their later-diagnosed peers, despite arguably representing a higher-risk cohort. The authors suggest that this may have resulted from earlier intervention and point to this approximate gestation as a beneficial screening point, as interventions can be made prior to the development of a functional fetal endocrine pancreas [ 50 ].…”