Continuous glucose monitoring in individuals undergoing gestational diabetes screening

BACKGROUND

Among guidelines on gestational diabetes mellitus, there is an incongruity about the threshold of maternal hyperglycemia to diagnose gestational diabetes mellitus.

OBJECTIVE

This study aimed to ascertain the association between continuous glucose monitoring metrics and adverse outcomes among individuals undergoing gestational diabetes mellitus screening.

STUDY DESIGN

This was a prospective study (from June 2020 to January 2022) of individuals who underwent 2-step gestational diabetes mellitus screening at ≤30 weeks of gestation. The participants wore a blinded continuous glucose monitoring device (Dexcom G6 Pro; Dexcom, Inc, San Diego, CA) for 10 days starting when they took the 50-g glucose challenge test. The primary outcome was a composite of adverse neonatal outcomes (large for gestational age, shoulder dystocia or neonatal injury, respiratory distress, need for intravenous glucose treatment for hypoglycemia, or fetal or neonatal death). The secondary neonatal outcomes included preterm birth, neonatal intensive care unit admission, hypoglycemia, mechanical ventilation or continuous positive airway pressure, hyperbilirubinemia, and hospital length of stay. The secondary maternal outcomes included weight gain during pregnancy, hypertensive disorders of pregnancy, induction of labor, cesarean delivery, and postpartum complications. Time within the target range (63-140 mg/dL), time above the target range (>140 mg/dL) expressed as a percentage of all continuous glucose monitoring readings, and mean glucose level were analyzed. The Youden index was used to choose the threshold of ≥10% for the time above the target range and association with adverse outcomes.

RESULTS

Of 136 participants recruited, data were available from 92 individuals (67.6%). The 2-step method diagnosed gestational diabetes mellitus in 2 individuals (2.2%). Continuous glucose monitoring indicated that 17 individuals (18.5%) had time above the target range of ≥10%. Individuals with time above the target range of ≥10% had a significantly higher likelihood of composite adverse neonatal outcomes than individuals with time above the target range of <10% (63% vs 18%; P=.001). Furthermore, compared with neonates born to individuals with time above the target range of <10%, neonates born to individuals with time above the target range of ≥10% had an increased likelihood for hypoglycemia (14.5% vs 47%; P=.009) and had a longer length of stay (2 vs 4 days; P=.03). No difference in maternal outcomes was noted between the groups.

CONCLUSION

In this prospective study of individuals undergoing gestational diabetes mellitus screening, a cutoff of the time above the target range of ≥10% using continuous glucose monitoring was associated with a higher rate of neonatal adverse outcomes. A randomized trial of continuous glucose monitoring vs 2-step screening for gestational diabetes mellitus to lower the rate of adverse outcomes is underway (identification number: NCT05430204).

Association of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms with vitamin B12 deficiency and adverse perinatal outcomes among pregnant women of rural South India - a cross sectional longitudinal study

OBJECTIVES

To determine the occurrence of MTHFR gene polymorphisms and to study their association with vitamin B12 deficiency and adverse perinatal outcomes among a cohort of pregnant women from Kaniyambadi block, Tamil Nadu.

METHODS

120 consecutive pregnant women who were ≤20 weeks of gestational age from the 82 villages of Kaniyambadi block were recruited. Genomic DNA was isolated from the peripheral blood. PCR amplification was done followed by Sangers sequencing. Maternal and neonatal outcomes were extracted. Data was entered and analysed.

RESULTS

Our study found the occurrence of c.1298A>C variant in homozygous state in 14.2% and c.677C>T heterozygous state in 15%. Sanger sequencing of exon 7 identified another pathogenic variant c.1262G>T in heterozygous state in two of them. Both the mothers who harboured that variant had preterm delivery and one of them gave birth to a low-birth-weight neonate. In the entire cohort, 5% of the mothers had abortion, 4.2% of them had preterm delivery and 8.8% of the neonates had low birth weight. Presence of c.1298A>C or c.677C>T variants were associated with vitamin B12 deficiency [Pearson Chi squared value (χ²)=7.9 and 7.6 respectively; p=0.02]. Heterozygous pathogenic variant c.1262G>T was associated with both adverse maternal [χ²=11.5; p=0.001] and neonatal [χ²=18.3; p=0.009] outcomes.

CONCLUSIONS

MTHFR gene polymorphisms could be associated with several adverse perinatal outcomes and vitamin B12 deficiency. Further larger studies are needed to prove the pathogenicity of c.1262G>T variant on pregnancy.

Serum vitamin D-binding protein (VDBP) concentration and rs7041 genotype may be associated with preterm labor

PURPOSE

Vitamin D deficiency is common during pregnancy and may cause complications such as preterm labor (PTL). This study was aimed to investigate the effect of the vitamin D-binding protein (VDBP) rs7041 genotype, which has a significant effect on vitamin D metabolism and PTL.

METHODS

This cross-sectional study was conducted with 32 pregnant women who had spontaneous PTL and 54 pregnant women who had no specific findings as a control group. Serum total vitamin D 25-hydroxy vitamin D (25(OH)D) levels were measured using the Elecsys Vitamin D Total Kit. VDBP was measured using a VDBP Quantikine ELISA Kit. The levels of bioavailable 25(OH)D were calculated based on the total 25(OH)D and VDBP concentrations. DNA was extracted using the DNeasy Blood and Tissue Kit. Single nucleotide polymorphisms (rs7041) in GC were analyzed using a TaqMan SNP Genotyping Assay Kit. The unpaired t-test, Chi-squared, and ANCOVA tests were performed. Firth's penalized logistic regression was applied. The area under the curve (AUC) was calculated and the cutoff value was determined. All statistical analyses were performed using R version 4.0.3 (R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

Total 25(OH)D levels were not significantly different between the two groups. Bioavailable 25(OH)D was significantly decreased in PTL women (p= .011), and VDBP was significantly increased in PTL women (p= .004) compared to the controls. Bioavailable 25(OH)D was lower in women with GT/TG and TT rs7041 genotypes than in those with GG, with statistical significance in women with the TT allele (p= .048). VDBP was higher in women with GT/TG and TT than those with GG, but there was no statistical significance. In PTL prevalence, bioavailable 25(OH)D and VDBP, the odds ratio increased by 1.463 times in GT/TG (p= .728) and increased by 1.675 times in TT compared to the GG allele (p= .640). In receiver operating characteristic (ROC) analysis for bioavailable 25(OH)D and VDBP, the AUC was 0.665 and 0685, respectively. The optimum cutoff of bioavailable 25(OH)D and VDBP levels for the diagnosis of PTL was calculated as 0.6 ng/mL and 523 µg/mL, respectively.

CONCLUSIONS

Pregnant women with the VDBP rs7041(c.1296 T > G) T allele genotype had reduced serum levels of bioavailable 25(OH)D and were more likely to develop PTL. Therefore, if the T allele is found in the VDBP rs7041 SNP genotyping test before or during pregnancy, more careful prenatal care may be required because of the increased risk of PTL.

Association between apgar score at 5 minutes and adverse outcomes among Low-Risk pregnancies

Objective: Among low-risk pregnancies, we aimed to ascertain the association between 5-minute Apgar score and adverse outcomes of newborn-maternal dyad.Study design: We conducted a retrospective cohort study using the U.S. vital statistics datasets (2012-2016), including live births from low-risk women with non-anomalous singleton gestations who delivered at 37-41 weeks. Apgar score was categorized as low (0-3), moderate (4-6), and normal (7-10). The primary outcome was composite neonatal adverse outcome (any of the following: assisted ventilation > 6 h, neonatal seizure, or neonatal death). The secondary outcomes were infant mortality and composite maternal adverse outcome (any of the following: admission to the intensive care unit, blood transfusion, uterine rupture, or unplanned hysterectomy). Multivariable Poisson regression analyses were used to estimate the association between 5-minute Apgar score and adverse outcomes (using adjusted relative risk [aRR] and 95% confidence intervals [CI]).Results: Of 19.9 million live births delivered between 2012 and 2016, 11.7 million (58.7%) met inclusion criteria; 98.9% had a normal 5-minute Apgar score, 0.9% had a moderate score, and 0.2% had a low score. The overall composite neonatal adverse outcome was 3.2 per 1,000 live births and the rates were significantly higher among those with a moderate (aRR 20.8; 95% CI 20.2-21.4) or low score (aRR 43.1; 95% CI 41.6-44.5) than normal score. The overall composite maternal adverse outcome was 2.45 per 1,000 live births and it was significantly higher in deliveries with a moderate (aRR 3.1; 95% CI 2.9-3.3) and low (aRR 4.6; 95% CI 4.2-5.0) 5-minute Apgar score than those with a normal score. Infant mortality also showed a similar pattern.Conclusion: Though approximate 1% of live births had a 5-minute Apgar score below 7 among low-risk pregnancies, a decreased score was associated with a significantly higher risk of neonatal and maternal adverse outcomes, as well as infant mortality.