Pregnancy outcomes associated with an abnormal 50-g glucose screen during pregnancy: a systematic review and Meta-analysis.

OBJECTIVE: To assess the association between an abnormal 1-h 50-g glucose challenge test (GCT) followed by a normal 3-h 100-g glucose tolerance test (GTT) on fetal macrosomia and other adverse outcomes. DATA SOURCES: MEDLINE, Cochrane, clinicaltrials.gov, and Google Scholar were searched from inception to March 2019. METHODS OF STUDY SELECTION: Any studies reporting adverse perinatal and/or maternal outcomes in women with an abnormal 50-g 1-h glucose challenge test (GCT) followed by a normal 3-h, 100-g glucose tolerance test (GTT) were included. Studies were critically appraised by three independent reviewers. Outcomes included fetal macrosomia, cesarean delivery, preeclampsia, birth weight, neonatal hypoglycemia, shoulder dystocia, NICU admission, respiratory morbidity, and low Apgar score. A random-effects model was employed to calculate pooled odds ratios (OR) for each outcome with their 95% confidence intervals (CI) and 95% predictive intervals (PI). TABULATION, INTEGRATION, AND RESULTS: We identified 30 studies comprising 18,067 patients with a normal 3-h GTT after an abnormal 1-h GCT (study group) and 117,091 patients with a normal 1-h, 50-g GCT (comparison group). Patients in the study group had an increased risk of macrosomia (OR 1.68, 95% CI 1.48-1.91, 27 studies, 132,027 patients), cesarean delivery (OR 1.39, 95% CI 1.30-1.48, 24 studies, 128,495 women), preeclampsia (OR 1.48, 95% CI 1.15-1.91, 17 studies, 110,930 patients), hypoglycemia (OR 1.43, CI 1.07-1.91) and shoulder dystocia (OR 1.52, 95% CI 1.09-2.12, 9 studies, 41,229 patients). Neonatal birth weight was significantly higher in the study group. The incidence of NICU admission, low Apgar score, and respiratory morbidity was similar in the two groups. Controlling for body mass index and 1-h glucose screen cut off did not alter these results. CONCLUSION: Even in the absence of gestational diabetes, patients who fail the GCT test are at mildly increased risk of maternal and neonatal morbidity including macrosomia, cesarean delivery, preeclampsia, and shoulder dystocia.

A Low 50-gram, 1-hour Glucose Challenge Test Value Predicts Neonatal Birth Weight Less than the 10th Percentile: A Systematic Review and Meta-Analysis.

OBJECTIVE: This study aimed to perform a systematic review with meta-analysis to investigate if women with a low 50-g, 1-hour glucose challenge test (GCT) value are at risk for having neonates with a birth weight less than the 10th percentile. STUDY DESIGN: A computerized literature search was conducted to identify studies that compared outcomes of pregnant women with a low GCT value versus women with a normal GCT value during routine screening for gestational diabetes. RESULTS: Sixteen cohort studies were included for analysis. Women with a low GCT value were noted to have a 43% increased odds of having neonates with birth weight less than the 10th percentile (odds ratio [OR]: 1.43; 95% confidence interval [CI]: 1.28-1.60) and 30% increased odds of having neonates with a birth weight less than 2,500 g (OR: 1.3; 95% CI: 1.0-1.7) when compared with women with a normal GCT value. The rates of preterm delivery, neonatal intensive care unit (NICU) admission, pregnancy-induced hypertension (PIH)/preeclampsia, respiratory distress, NICU, and Apgar scores less than 7 were similar in the two groups. CONCLUSION: A low GCT value defined as less than 90 mg/dL identifies pregnancies at elevated risk for having neonates with a birth weight less than the 10th percentile.

Assessing White's classification of pregestational diabetes in a contemporary diabetic population.

OBJECTIVE: To assess the validity of White's classification, including the role of chronic hypertension, in a contemporary diabetic population. METHODS: We performed a retrospective cohort study of all singleton pregnancies with pre-existing diabetes mellitus from 2008 to 2013. Adverse outcomes were compared across classes B, C, D, and vascular disease (R, F, H) and further stratified by the presence or absence of chronic hypertension. Outcomes examined were a composite perinatal outcome (stillbirth, neonatal death, shoulder dystocia, birth injury, seizures, requiring chest compressions or intubation at delivery, blood pressure support), small for gestational age (SGA), large for gestational age (LGA), macrosomia, shoulder dystocia, preterm delivery at less than 37 weeks of gestation, preeclampsia, and cesarean delivery. RESULTS: Of the 475 patients, the 1980 White's classification was significantly associated with SGA, LGA, macrosomia, preterm delivery, preeclampsia, and cesarean delivery (P≤.01). Within each White's class based on age or time since diagnosis alone, hypertension was significantly associated with a higher incidence of preeclampsia in class B (16% without hypertension compared with 32% with hypertension, P<.01) and C (22% compared with 40%, P=.04), SGA in C (4.7% compared with 21%, P<.01), preterm delivery in B (25% compared with 46%, P<.01) and C (35% compared with 58%, P=.01), and the composite neonatal outcome in B (7.9% compared with 17%, P=.03). The incidence of adverse outcomes in classes B and C with hypertension resembles the incidence of adverse outcomes in those with diabetes one class higher. CONCLUSION: The 1980 White's classification system, taking into consideration the presence of chronic hypertension, remains a useful system for counseling pregestational diabetic women regarding adverse pregnancy outcomes. LEVEL OF EVIDENCE: II.