The Association Between Low 50 g Glucose Challenge Test Values and Adverse Pregnancy Outcomes

The association between a low 50-gram, 1-hour glucose challenge test value and neonatal morbidity

OBJECTIVE

To evaluate the association between a low 50-gram, 1-hour glucose challenge test (GCT) value and adverse maternal and neonatal outcomes among patients receiving care at a single center tertiary care academic hospital.

METHODS

We performed a retrospective cohort study of pregnant patients with a documented result of a 50-gram, 1-hour GCT performed ≥24 weeks 0 days gestation at a single tertiary care academic hospital from 2013-2021. Patients with a low GCT value, defined as cohort specific ≤10th percentile (<82 mg/dL), were compared to patients with a GCT value ≥82 mg/dL who were not diagnosed with gestational diabetes (GDM) to examine adverse maternal and neonatal outcomes. Additionally, these comparisons were repeated across patients with low GCT (<82 mg/dL), those with a GCT ≥82 mg/dL without diagnosis of GDM (heretofore referred to as normal glycemic screening) and patients diagnosed with GDM. Our primary outcome was a composite neonatal morbidity variable, inclusive of stillbirth, neonatal death, neonatal hypoglycemia with neonatal intensive care unit (NICU) admission, neonatal hyperbilirubinemia with NICU admission, respiratory distress with NICU admission, and/or small for gestational age (SGA). Multivariable logistic regression modeling was used to examine the association of low GCT value and the composite neonatal morbidity outcome, compared to those with the normal glycemic screening.

RESULTS

Of 36,342 eligible patients, 3,789 (10.4%) had a low GCT value of <82 mg/dL, 30,729 (84.6%) had a GCT value ≥82 mg/dL and were not diagnosed with GDM, and 1,824 (5.0%) had a diagnosis of GDM. Patients with a low GCT value were significantly less likely to be diagnosed with hypertensive disorder of pregnancy (HDP) (12.4% vs 16.3%, p < .01), undergo cesarean delivery (22.8% vs 29.9%, p < .01), or experience postpartum hemorrhage (7.8% vs 9.4%, p < .01) as compared to patients with normal glycemic screening. Compared to newborns whose mothers had normal glycemic screening, newborns of mothers with a low GCT value were significantly more likely to experience the composite morbidity outcome (OR 1.17; 95% CI 1.08-1.27); this persisted after adjusting for potential confounders (aOR 1.18; 95% CI 1.09-1.29).

CONCLUSION

A low maternal GCT value after 24 weeks gestation is significantly associated with an increased risk of morbidity in the newborn, driven by higher rates of SGA. Patients with a low GCT value may have underlying maternal hypoglycemia or other glycemic dysregulation affecting fetal development and may benefit from enhanced antenatal surveillance.

Alcohol blunts pregnancy-mediated insulin resistance and reduces fetal brain glucose despite elevated fetal gluconeogenesis, and these changes associate with fetal weight outcomes

Prenatal alcohol exposure (PAE) impairs fetal growth and neurodevelopment. Although alcohol is well known to alter metabolism, its impact on these processes during pregnancy is largely unexplored. Here, we investigate how alcohol affects maternal-fetal glucose metabolism using our established mouse binge model of PAE. In the dam, alcohol reduces the hepatic abundance of glucose and glycolytic intermediates, and the gluconeogenic enzymes glucose-6-phosphtase and phosphoenolpyruvate carboxykinase. Fasting blood glucose is also reduced. In a healthy pregnancy, elevated maternal gluconeogenesis and insulin resistance ensures glucose availability for the fetus. Glucose and insulin tolerance tests reveal that alcohol impairs the dam's ability to acquire insulin resistance. Alcohol-exposed dams have enhanced glucose clearance (p < .05) in early gestation, after just two days of alcohol, and this persists through late term when fetal glucose needs are maximal. However, maternal plasma insulin levels, hepatic insulin signaling, and the abundance of glucose transporter proteins remain unchanged. In the PAE fetus, the expression of hepatic gluconeogenic genes is elevated, and there is a trend for elevated blood and liver glucose levels. In contrast, fetal brain and placental glucose levels remain low. This reduced maternal fasting glucose, reduced hepatic glucose, and elevated glucose clearance inversely correlated with fetal body and brain weight. Taken together, these data suggest that alcohol blunts the adaptive changes in maternal glucose metabolism that otherwise enhance fetal glucose availability. Compensatory attempts by the fetus to increase glucose pools via gluconeogenesis do not normalize brain glucose. These metabolic changes may contribute to the impaired fetal growth and brain development that typifies PAE.

Normal glucose tolerant women with low glycemia during the oral glucose tolerance test have a higher risk to deliver a low birth weight infant

Background

Data are limited on pregnancy outcomes of normal glucose tolerant (NGT) women with a low glycemic value measured during the 75g oral glucose tolerance test (OGTT). Our aim was to evaluate maternal characteristics and pregnancy outcomes of NGT women with low glycemia measured at fasting, 1-hour or 2-hour OGTT.

Methods

The Belgian Diabetes in Pregnancy-N study was a multicentric prospective cohort study with 1841 pregnant women receiving an OGTT to screen for gestational diabetes (GDM). We compared the characteristics and pregnancy outcomes in NGT women according to different groups [(<3.9mmol/L), (3.9-4.2mmol/L), (4.25-4.4mmol/L) and (>4.4mmol/L)] of lowest glycemia measured during the OGTT. Pregnancy outcomes were adjusted for confounding factors such as body mass index (BMI) and gestational weight gain.

Results

Of all NGT women, 10.7% (172) had low glycemia (<3.9 mmol/L) during the OGTT. Women in the lowest glycemic group (<3.9mmol/L) during the OGTT had compared to women in highest glycemic group (>4.4mmol/L, 29.9%, n=482), a better metabolic profile with a lower BMI, less insulin resistance and better beta-cell function. However, women in the lowest glycemic group had more often inadequate gestational weight gain [51.1% (67) vs. 29.5% (123); p<0.001]. Compared to the highest glycemia group, women in the lowest group had more often a birth weight <2.5Kg [adjusted OR 3.41, 95% CI (1.17-9.92); p=0.025].

Conclusion

Women with a glycemic value <3.9 mmol/L during the OGTT have a higher risk for a neonate with birth weight < 2.5Kg, which remained significant after adjustment for BMI and gestational weight gain.

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.

Prediction of low birth weight with hypoglycemia in glucose tolerance test

OBJECTIVE:

Determine the value of the combination of fasting glucose less than the 10th percentile (FG < p10) during 75 gram oral glucose tolerance test (75g OGTT) with maternal characteristics to predict low birth weight (LBW) established by Intergrowth-21st tables.

METHODS:

Prospective cohort study of pregnant women who was underwent 75g OGTT between 24 and 28.6 weeks. The 10th percentile fasting glucose of the population was determined at 65 mg/dL and women with risk factors that could modify fetal weight, including those related to intrauterine growth restriction, were excluded. Two groups were formed: group FG < p10 and group with normal fasting glucose. The main finding was the diagnosis of LBW. The association between FG < p10, maternal characteristics and LBW was established by multivariate logistic regression. The predictive performance of the models constructed was evaluated by receiver operating characteristic (ROC) curve and area under the curve (AUC) analysis.

RESULTS:

349 women were eligible for study, of whom 66 (18.91%) had FG < p10; neonates in this group had lower birth weights (2947.28 g and 3138.26 g, p = 0.001), higher frequencies of LBW (25% and 6.81%, p < 0.001) and of weights < 2500 g in term births (8.6% and 2.3%, p = 0.034). The basal prediction model consisted of nulliparity by achieving an AUC of 60%, while the addition of FG < p10 resulted in the significant improvement of the previous model (AUC 72%, DeLong: p = 0.005).

CONCLUSIONS:

In pregnant women without factors that could modify fetal weight, the predictive model created by combining FG < p10 during 75g OGTT with nulliparity was significantly associated with increased risk of LBW.

REGISTRATION:

ClinicalTrials.gov: NCT04144595.

Use of the 50-g glucose challenge test to predict small-for-gestational-age neonates

BACKGROUND

To determine a cutoff value for the 50-g glucose challenge test (50-g GCT) for the prediction of small-for-gestational-age (SGA) neonates.

METHODS

This retrospective cohort study was conducted among pregnant women who were screened with the 50-g GCT at Hacettepe University Hospital between 1 January 2016 and 31 March 2019. Patients with 50-g GCT values <74 mg/dL (<10th percentile) served as the study group (n = 244), while patients with 50-g GCT values between 74 to 139 mg/dL served as the control group (n = 3104). Groups were compared in terms of demographic features, clinical characteristics, and obstetric outcomes. Logistic regression analysis was used to determine independent predictors of SGA. Receiver operating characteristic curves were used to assess the performance of 50-g GCT values in predicting SGA.

RESULTS

Lower birthweight, birthweight percentile, and 5th-minute Apgar values, together with higher rates of SGA, were observed in the study group (P < .001 for all). A 50-g GCT value below the 10th percentile (odds ratio: 3.29, 95% CI: 2.31-4.69, P < .001) was a significant independent factor for SGA. A cutoff value of 89.5 mg/dL (84.9% sensitivity, 85.6% specificity) was determined for SGA.

CONCLUSIONS

Low 50-g GCT values (<89.5 mg/dL) may be an early indicator for SGA.