The impact of first trimester fasting glucose level on adverse perinatal outcome

Early screening for gestational diabetes mellitus: a meta-analysis of randomized controlled trials

OBJECTIVE

Current evidence is conflicting on whether early screening and treatment for gestational diabetes mellitus improve pregnancy outcomes. Thus, this systematic review and meta-analysis of randomized controlled trials aimed to assess the rate of adverse pregnancy outcomes among participants with early screening and treatment for gestational diabetes mellitus vs those with routine care.

DATA SOURCES

A systematic review of the literature was conducted using MEDLINE, Scopus, ClinicalTrials.gov, EMBASE, ScienceDirect, the Cochrane Library at the Central Register of Controlled Trials, and SciELO from inception to November 2021.

STUDY ELIGIBILITY CRITERIA

Studies were eligible for inclusion if they described randomized controlled trials comparing early screening with routine care for gestational diabetes mellitus to assess the effects of early screening and treatment on pregnancy outcomes.

METHODS

All randomized controlled trials comparing early vs standard screening of gestational diabetes mellitus assessing the effect of early screening (defined as a screening at <20 weeks of gestation) vs routine screening (defined as a screening at ≥20 weeks of gestation) on pregnancy outcomes were included. The primary outcome was defined as large for gestational age, as defined by the trial. The secondary maternal and neonatal outcomes were also evaluated. Subgroup analyses were performed on the basis of screening strategy and methods.

RESULTS

After exclusion, 8 randomized clinical trials (1920 participants) of early screening and treatment vs standard care were included. There were a total of 746 participants with early gestational diabetes mellitus. The risk of large for gestational age at birth did not differ between early screening and treatment for gestational diabetes mellitus and routine care among all included trials (8.1 vs 9.0%; relative risk, 0.94; 95% confidence interval, 0.73-1.22). Trials with a protocol of universal screening of participants at their first prenatal visit (>80% screened with HbA1c) and receiving early treatment if the screening test returned positive had a lower risk of large for gestational age (2.3 vs 9.1%; relative risk, 0.29; 95% confidence interval, 0.09-0.90) than those who had routine screening and care.

CONCLUSION

Overall, early screening and treatment of gestational diabetes mellitus did not reduce the risk of large for gestational age at birth. However, trials that screened all participants at their first visit and treated early, most for an HbA1c of 5.7% to 6.4%, had a reduced risk of large for gestational age at birth compared with routine care, suggesting a possible benefit of screening all pregnant patients. However, future well-designed trials are needed to confirm these findings.

Comparison of Gut Microbiota and Metabolic Status of Sows With Different Litter Sizes During Pregnancy

The experiment was conducted to compare the differences of gut microbiota and metabolic status of sows with different litter sizes on days 30 and 110 of gestation, and uncover the relationship between the composition of maternal gut microbiota during gestation and sow reproductive performance. Twenty-six Large White × Landrace crossbred multiparous sows (2nd parity) with similar back fat thickness and body weight were assigned to two groups [high-reproductive performance group (HP group) and low-reproductive performance group (LP group)] according to their litter sizes and fed a common gestation diet. Results showed that compared with LP sows, HP sows had significantly lower plasma levels of triglyceride (TG) on gestation d 30 (P < 0.05), but had significantly higher plasma levels of TG, non-esterified fatty acid, tumor necrosis factor-α, and immunoglobulin M on gestation d 110 (P < 0.05). Consistently, HP sows revealed increased alpha diversity and butyrate-producing genera, as well as fecal butyrate concentration, on gestation d 30; HP sows showed significantly different microbiota community structure with LP sows (P < 0.05) and had markedly higher abundance of Firmicutes (genera Christensenellaceae_R-7_group and Terrisporobacter) which were positively related with litter size on gestation d 110 than LP sows (P < 0.05). In addition, plasma biochemical parameters, plasma cytokines, and fecal microbiota shifted dramatically from gestation d 30 to d 110. Therefore, our findings demonstrated that microbial abundances and community structures differed significantly between sows with different litter sizes and gestation stages, which was associated with changes in plasma biochemical parameters, inflammatory factors, and immunoglobulin. Moreover, these findings revealed that there was a significant correlation between litter size and gut microbiota of sows, and provided a microbial perspective to improve sow reproductive performance in pig production.

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

The incidence of gestational diabetes mellitus (GDM) is increasing worldwide. This has a significant effect on the health of the mother and offspring. There is no doubt that screening for GDM between 24 and 28 weeks is important to reduce the risk of adverse pregnancy outcomes. However, there is no consensus about diagnosis and treatment of GDM in early pregnancy. In this narrative review on the current evidence on screening for GDM in early pregnancy, we included 37 cohort studies and eight randomized controlled trials (RCTs). Observational studies have shown that a high proportion (15–70%) of women with GDM can be detected early in pregnancy depending on the setting, criteria used and screening strategy. Data from observational studies on the potential benefit of screening and treatment of GDM in early pregnancy show conflicting results. In addition, there is substantial heterogeneity in age and BMI across the different study populations. Smaller RCTs could not show benefit but several large RCTs are ongoing. RCTs are also necessary to determine the appropriate cut-off for HbA1c in pregnancy as there is limited evidence showing that an HbA1c ≥6.5% has a low sensitivity to detect overt diabetes in early pregnancy.

Risk Factors Screening for Gestational Diabetes Mellitus Heterogeneity in Chinese Pregnant Women: A Case-Control Study

PURPOSE

To study the risk factors of gestational diabetes mellitus (GDM) heterogeneity, and to evaluate the correlation between the risk factors and obesity.

METHODS

We performed a case-control study of 452 women with GDM and 516 women with normal glucose tolerance (NGT) at the first and second trimester. We defined GDM women as GDM-resistance subtype, GDM-dysfunction subtype, and GDM-mixed subtype, according to their simultaneous insulin-release test with predominant insulin-sensitivity defect, insulin-secretion defect, or both defects.

RESULTS

We found that higher maternal age, family history of diabetes, the elevated level of fasting blood glucose in the first trimester (≥5.1 mmol/L) were risk factors of all GDM subtypes. Pre-pregnancy overweight/obesity and the increased gestational weight gain (GWG) in the first-trimester are risk factors of the GDM-resistance subtype. Indicators including younger age at first menstruation, the elevated levels of alanine aminotransferase (ALT), total bile acid (TBA), triglyceride (TG), and the decreased level of high-density lipoprotein cholesterol (HDL-C) are risk factors of the GDM-resistance subtype. However, the associations between those risk factors and GDM-resistance subtype attenuated after adjusted by pre-pregnancy body mass index (pre-BMI) and gestational weight gain (GWG) in the first trimester. Nonalcoholic fatty liver disease (NAFLD) and the improved level of TG are independent risk factors for the GDM-resistance subtype and the GDM-mixed subtype, respectively.

CONCLUSION

Women with GDM exhibited heterogeneity based on glycemic physiology and their risk factors are not all the same. Some obesity-related risk factors are specific to the GDM-resistance subtype, which are mediated by pre-pregnancy overweight/obesity and the elevated GWG the first-trimester.

In ovo hyperglycemia causes congenital limb defects in chicken embryos via disruption of cell proliferation and apoptosis

While the correlation between diabetes during pregnancy and birth defects is well-established, how hyperglycemia causes developmental abnormalities remains unclear. In this study, we developed a novel "hyperglycemic" chicken embryonic model by administrating various doses of glucose to fertilized eggs at embryonic stages HH16 or HH24. When the embryos were collected at HH35, the LD50 was 1.57 g/Kg under HH16 treatment and 0.93 g/Kg under HH24 treatment, indicating that "hyperglycemic" environments can be lethal for the embryos. When exposed to a dose equal to or higher than 1 g/Kg glucose at HH16 or HH24, more than 40% of the surviving chicken embryos displayed heart defects and/or limb defects. The limb defects were associated with proliferation defects of both the wing and leg buds indicated by reduced numbers of p-H3S10 labeled cells. These limb defects were also associated with ectopic apoptosis in the leg bud and expression changes of key apoptotic genes. Furthermore, glucose treatment induced decreased expression of genes involved in Shh-signaling, chondrogenesis, and digit patterning in the limb bud. In summary, our data demonstrated that a high-glucose environment induces congenital heart and limb defects associated with disrupted cell proliferation and apoptosis, possibly through depressed Shh-signaling.