Low values on 50 gram glucose challenge test or oral 100 gram glucose tolerance test are associated with good perinatal outcome

Abdominal subcutaneous fat thickness combined with a 50-g glucose challenge test at 24-28 weeks of pregnancy in predicting gestational diabetes mellitus

BACKGROUND

This investigation aimed to analyse the efficacy of abdominal subcutaneous fat thickness (ASFT) value >18.1 mm combined with a 50-g glucose challenge test (GCT) between 24-28 weeks of gestation in predicting gestational diabetes mellitus (GDM) cases.

METHODS

This cross-sectional study was carried out from February 2021 to December 2022. All pregnant women received a 50-g GCT at 24-28 weeks of pregnancy for the GDM screening. Pregnant women with a blood glucose value between 140-190 mg/dl experienced 100 g OGTT. Even if 50-g GCT was normal, 100-g OGTT was offered to patients with an ASFT value above 18.1 mm.

RESULTS

Among the 728 pregnant women we enrolled, 154 (21.2%) cases were screened as positive. The number of patients who first screened positive and determined to be GDM after the 100-g oral glucose tolerance test (OGTT) was 43 (5.9%). A total of 67 cases (9.2%) had an ASFT measurement above 18.1 mm. Two cases with a negative 50-g GCT and ASFT <18.1 mm were diagnosed as GDM in the later weeks of pregnancy. A 50-g GCT combined with ASFT measurement above 18.1 mm predicted GDM with a sensitivity of 87.9%, a specificity of 88.7%, a positive predictive value (PPV) of 36.0%, and a negative PV (NPV) of 99.7%.

CONCLUSIONS

A 50-g GCT combined with ASFT measurement that can be easily and accurately obtained during routine antenatal care in the second trimester might be a beneficial indicator for predicting GDM cases.

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.

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.

The identification and treatment of women with hyperglycaemia in pregnancy: an analysis of individual participant data, systematic reviews, meta-analyses and an economic evaluation

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with a higher risk of important adverse outcomes. Practice varies and the best strategy for identifying and treating GDM is unclear.

AIM

To estimate the clinical effectiveness and cost-effectiveness of strategies for identifying and treating women with GDM.

METHODS

We analysed individual participant data (IPD) from birth cohorts and conducted systematic reviews to estimate the association of maternal glucose levels with adverse perinatal outcomes; GDM prevalence; maternal characteristics/risk factors for GDM; and the effectiveness and costs of treatments. The cost-effectiveness of various strategies was estimated using a decision tree model, along with a value of information analysis to assess where future research might be worthwhile. Detailed systematic searches of MEDLINE^® and MEDLINE In-Process & Other Non-Indexed Citations^®, EMBASE, Cumulative Index to Nursing and Allied Health Literature Plus, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment database, NHS Economic Evaluation Database, Maternity and Infant Care database and the Cochrane Methodology Register were undertaken from inception up to October 2014.

RESULTS

We identified 58 studies examining maternal glucose levels and outcome associations. Analyses using IPD alone and the systematic review demonstrated continuous linear associations of fasting and post-load glucose levels with adverse perinatal outcomes, with no clear threshold below which there is no increased risk. Using IPD, we estimated glucose thresholds to identify infants at high risk of being born large for gestational age or with high adiposity; for South Asian (SA) women these thresholds were fasting and post-load glucose levels of 5.2 mmol/l and 7.2 mmol/l, respectively and for white British (WB) women they were 5.4 and 7.5 mmol/l, respectively. Prevalence using IPD and published data varied from 1.2% to 24.2% (depending on criteria and population) and was consistently two to three times higher in SA women than in WB women. Lowering thresholds to identify GDM, particularly in women of SA origin, identifies more women at risk, but increases costs. Maternal characteristics did not accurately identify women with GDM; there was limited evidence that in some populations risk factors may be useful for identifying low-risk women. Dietary modification additional to routine care reduced the risk of most adverse perinatal outcomes. Metformin (Glucophage,^® Teva UK Ltd, Eastbourne, UK) and insulin were more effective than glibenclamide (Aurobindo Pharma - Milpharm Ltd, South Ruislip, Middlesex, UK). For all strategies to identify and treat GDM, the costs exceeded the health benefits. A policy of no screening/testing or treatment offered the maximum expected net monetary benefit (NMB) of £1184 at a cost-effectiveness threshold of £20,000 per quality-adjusted life-year (QALY). The NMB for the three best-performing strategies in each category (screen only, then treat; screen, test, then treat; and test all, then treat) ranged between -£1197 and -£1210. Further research to reduce uncertainty around potential longer-term benefits for the mothers and offspring, find ways of improving the accuracy of identifying women with GDM, and reduce costs of identification and treatment would be worthwhile.

LIMITATIONS

We did not have access to IPD from populations in the UK outside of England. Few observational studies reported longer-term associations, and treatment trials have generally reported only perinatal outcomes.

CONCLUSIONS

Using the national standard cost-effectiveness threshold of £20,000 per QALY it is not cost-effective to routinely identify pregnant women for treatment of hyperglycaemia. Further research to provide evidence on longer-term outcomes, and more cost-effective ways to detect and treat GDM, would be valuable.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013004608.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Small-for-gestational age and its association with maternal blood glucose, body mass index and stature: a perinatal cohort study among Chinese women

OBJECTIVE

To examine whether maternal low blood glucose (BG), low body mass index (BMI) and small stature have a joint effect on the risk of delivery of a small-for-gestational age (SGA) infant.

DESIGN

Women from a perinatal cohort were followed up from receiving perinatal healthcare to giving birth.

SETTING

Beichen District, Tianjin, China between June 2011 and October 2012.

PARTICIPANTS

1572 women aged 19-39 years with valid values of stature, BMI and BG level at gestational diabetes mellitus screening (gestational weeks 24-28), glucose challenge test <7.8 mmol/L and singleton birth (≥37 weeks' gestation).

MAIN OUTCOME MEASURES

SGA was defined as birth weight <10th centile for gender separated gestational age of Tianjin singletons.

RESULTS

164 neonates (10.4%) were identified as SGA. From multiple logistic regression models, the ORs (95% CI) of delivery of SGA were 0.84 (0.72 to 0.98), 0.61 (0.49 to 0.74) and 0.64 (0.54 to 0.76) for every 1 SD increase in maternal BG, BMI and stature, respectively. When dichotomises, maternal BG (<6.0 vs ≥6.0 mmol/L), BMI (<24 vs ≥24 kg/m(2)) and stature (<160.0 vs ≥160.0 cm), those with BG, BMI and stature all in the lower categories had ∼8 times higher odds of delivering an SGA neonate (OR (95% CI) 8.01 (3.78 to 16.96)) relative to the reference that had BG, BMI and stature all in the high categories. The odds for an SGA delivery among women who had any 2 variables in the lower categories were ∼2-4 times higher.

CONCLUSIONS

Low maternal BG is associated with an increased risk of having an SGA infant. The risk of SGA is significantly increased when the mother is also short and has a low BMI. This may be a useful clinical tool to identify women at higher risk for having an SGA infant at delivery.

Association between Prenatal One-Hour Glucose Challenge Test Values and Delivery Mode in Nondiabetic, Pregnant Black Women

Objective. We examined the association between 1-hour glucose challenge test (GCT) values and risk of caesarean section. Study Design. A prospective cohort study recruited 203 pregnant Black women to participate. At ~28 weeks of gestation, participants underwent a routine 1-hour 50 g GCT to screen for gestational diabetes mellitus. Logistic regression was used to examine the association between 1-hour GCT value and delivery mode. Results. Of the 158 participants included, 53 (33.5%) delivered via C-section; the majority (n = 29; 54.7%) were nulliparous. Mean 1-hour GCT values were slightly, but not significantly, higher among women delivering via C-section; versus vaginally (107.8 ± 20.7 versus 102.4 ± 21.5 mg/dL, resp.; P = 0.13). After stratifying by parity and adjusting for maternal age, previous C-section, and prepregnancy body mass index, 1-hour GCT value was significantly associated with increased risk of C-section among parous women (OR per 1 mg/dL increase in GCT value = 1.05; 95% CI OR: 1.00, 1.05; P = 0.045). Conclusion. Even slightly elevated 1-hour 50 g GCT values may be associated with delivery mode among parous Black women.

The association between low 50 g glucose challenge test result and fetal growth restriction

OBJECTIVE

To determine whether a low-GCT result is predictive of low birthweight and to identify the lower GCT threshold for prediction of fetal growth restriction.

METHODS

A retrospective cohort study of 12,899 women who underwent a GCT (24-28 weeks). Women with a low-GCT result (<10th percentile (70 mg/dL) were compared to women with normal-GCT result (70-140 mg/dL). ROC analysis was used to determine the optimal lower GCT threshold for the prediction of growth restriction.

RESULTS

Women in the low GCT had significant lower rates of cesarean delivery (18.7% versus 22.5%), shoulder dystocia (0.0% versus 0.3%), mean birthweight (3096 ± 576 versus 3163 ± 545) and birthweight percentile (49.1 ± 27.0 versus 53.1 ± 26.7) and significant higher rates of birthweight <2500 g (11.3% versus 8.5%), below the 10th percentile (8.3% versus 6.5%) and 3rd percentile (2.3% versus 1.4%). Low GCT was independently associated with an increased risk for birthweight <2500 g (OR = 1.6, 1.2-2.0), birthweight <10th percentile (OR = 1.3, 1.1-1.6), birthweight <3rd percentile (OR = 1.7, 1.2-2.5) and neonatal hypoglycemia (OR = 1.4, 1.02-2.0). The optimal GCT threshold for the prediction of birthweight <10th percentile was 88.5 mg/dL (sensitivity 48.5%, specificity 58.1%).

CONCLUSION

Low-GCT result is independently associated with low birthweight and can be used in combination with additional factors for the prediction of fetal growth restriction.

Mild gestational hyperglycemia and the metabolic syndrome in later life

BACKGROUND

Diabetes and obesity, components of the metabolic syndrome, are common longterm complications in women with previous gestational diabetes (pGDM). Long-term follow-up of women with mild gestational hyperglycemia is lacking.

METHODS

Fifty women with previous positive oral glucose challenge test and negative oral glucose tolerance test (pOGCT+OGTT-), 161 with previous normal glucose tolerance (pNGT), and 182 pGDM were studied after 6.5 years from the index pregnancy.

RESULTS

Patients with pGDM showed a worse metabolic pattern than pNGT. Women with pOGCT+OGTT- had significantly higher levels of fasting glucose, homeostasis model assessment (HOMA), percentage of impaired fasting glucose, and low age and high-density lipoprotein (HDL)-cholesterol than pNGT subjects. Prevalence of the metabolic syndrome (MS) was, respectively, sixfold and twofold higher in pGDM and pOGCT+OGTT- than in pNGT. In a Cox proportional hazard model, after multiple adjustments, pGDM was significantly associated with subsequent hyperglycemia (hazard ratio [HR] = 4.2; 95% CI 1.6-11.1), low HDL-cholesterol (HR = 1.7, 1.1-2.8), hypertriglyceridemia (HR = 4.2, 1.2-14.9), hypertension (HR = 2.2, 1.3-3.6), MS (HR = 3.7, 1.3-10.8), while pOGCT+OGTT- was associated with subsequent hyperglycemia (HR = 4.3, 1.3-14.7), and low HDL-cholesterol (HR = 2.0, 1.0-3.8). The metabolic syndrome was present in 52.6% of obese pGDM, 50% of obese pOGCT+OGTT-, and 28.6% of obese pNGT women; the corresponding HRs were, respectively, HR = 2.20, 0.74-6.57 (pGDM), and HR = 3.56, 1.10-11.5 (pOGCT+OGTT-).

CONCLUSIONS

Women who failed the OGCT, but not the OGTT, showed a subsequent worse metabolic pattern than pNGT subjects, independently of confounding factors. In the presence of obesity, the prevalence of the metabolic syndrome was similar to that of obese pGDM women, and almost twofold higher than in obese pNGT controls.