Metabolic Characteristics of Gestational Diabetes Mellitus and the Effects on Pregnancy Outcomes

Diabetes Mellitus and Pregnancy: An Insight into the Effects on the Epigenome

Worldwide, diabetes mellitus represents a growing health problem. If it occurs during pregnancy, it can increase the risk of various abnormalities in early and advanced life stages of exposed individuals due to fetal programming occurring in utero. Studies have determined that maternal conditions interfere with the genotypes and phenotypes of offspring. Researchers are now uncovering the mechanisms by which epigenetic alterations caused by diabetes affect the expression of genes and, therefore, the development of various diseases. Among the numerous possible epigenetic changes in this regard, the most studied to date are DNA methylation and hydroxymethylation, as well as histone acetylation and methylation. This review article addresses critical findings in epigenetic studies involving diabetes mellitus, including variations reported in the expression of specific genes and their transgenerational effects.

Evaluation of insulin secretion and insulin sensitivity in pregnant women: Application value of simple indices

The prevalence of gestational diabetes mellitus (GDM) is increasing annually, which poses substantial harm to the health of both mothers and children. Therefore, selection of clinically applicable and easily detectable indicators in the assessment of maternal insulin secretory function and insulin sensitivity in pregnant women undoubtedly holds great importance in evaluating the risk of GDM, guiding the choice of GDM therapy modalities, and improving the ability to provide early warning of adverse pregnancy outcomes. Compared with the classic clamp technique, many simple indices are more suited for use among pregnant women due to the low frequency of blood sampling and simple administration involved. While indices derived from fasting blood glucose and fasting insulin levels are most readily available, they are unable to provide information on the ability of insulin to manage the glucose load during pregnancy. Although the indices derived from the insulin and glucose values at each time point of the oral glucose tolerance test can provide a more comprehensive picture of the insulin sensitivity and insulin secretory function of the body, their application is constrained by the complexity of the procedure and associated high costs. Concomitantly, the findings from different studies are influenced by a variety of confounding factors, such as the gestational age during testing, race, and detection method. Furthermore, insulin secretory function and insulin sensitivity in pregnant women differ from those in non-pregnant women in that they change significantly with prolonged pregnancy; hence, there is an urgent need to develop a pregnancy-specific reference range. This article reviews the progress in the application of simple indices to help clinicians better understand their potential application in detecting GDM.

Interaction and joint association of gestational diabetes mellitus and subsequent weight gain rate on macrosomia

BACKGROUND & AIMS

Gestational diabetes mellitus (GDM) and gestational weight gain are two crucial modifiable nutritional factors during pregnancy in preventing macrosomia, warranting appropriate management of both glycemic levels and weight gain to prevent macrosomia, particularly in individuals with GDM. Unfortunately, current general weight targets appear not to apply to individuals with GDM, suggesting that weight gain, specifically following an oral glucose tolerance test (OGTT), may affect risk of macrosomia dependent on GDM status. Therefore, this study aims to evaluate the interaction and joint association of GDM and post-OGTT weight gain rate (PWGR) in relation to macrosomia.

METHODS

This was a population-based cohort study of 59,421singleton pregnant women in South China during 2017-2020. Among them, 9856 were diagnosed with GDM while 49,565 did not have the condition. All participants underwent an OGTT between 20 and 28 weeks of pregnancy, typically occurring between 24 and 28 weeks. PWGR was defined as the average rate of change in maternal weight with gestational weeks following OGTT, which was estimated using a repeated linear mixed effects model including a random intercept and slope for each individual. The relative risk (RR) of macrosomia associated with GDM and PWGR was estimated using a multivariate generalized linear model.

RESULTS

There was a significant interaction between GDM and PWGR in increasing the risk of macrosomia. The combination of GDM and a 1-SD increase in PWGR was associated with a 2.26-fold higher risk of macrosomia (95% CI 1.92 to 2.65), with the interaction of these two factors contributing to 58.0% (95% CI 31.4%-84.7%) of this association. Moreover, we observed a significant heterogeneity in susceptibility to macrosomia due to increased PWGR between GDM and non-GDM populations, with the highest PWGR quartile having respective RRs of 2.27 (95% CI 1.62 to 3.18) and 1.41 (95% CI 1.18 to 1.69) compared to the lowest quartile category, which was corresponded to 55.9% (95% CI 38.3%-68.6%) and 29.1% (95% CI 15.3%-40.8%) preventable proportions of macrosomia cases in these populations.

CONCLUSIONS

GDM and PWGR had a synergistic effect in increasing the risk of macrosomia. Furthermore, individuals with GDM exhibited a heightened susceptibility to macrosomia due to elevated PWGR. These findings emphasize the importance of appropriate weight interventions during late pregnancy and suggest the need for different weight targets between these two populations, with a stricter PWGR potentially being more effective for the GDM population.