Role of maternal glucose metabolism in the association between maternal BMI and neonatal size and adiposity

The mediating role of maternal fasting plasma glucose level and lipid levels in the third trimester of pregnancy between pre-pregnancy BMI and offspring physical development at birth

While previous research has established correlations between pre-pregnancy body mass index (BMI), late-pregnancy blood glucose, and late-pregnancy blood lipid levels during pregnancy and offspring's physical development, the underlying mechanism of their interaction remains elusive. A birth cohort study was conducted on pregnant women, who are biologically female, delivering at a tertiary hospital in Wuhan City between May 2023 and April 2024, encompassing 1620 participants. We collected maternal socio-demographic data through questionnaires and obtained information on fasting blood glucose (FPG), lipid levels during the third trimester, and neonatal physical development from medical records. This study aims to explore the correlation between pre-pregnancy BMI and offspring physical development by conducting statistical analyses and the mediating pathway of FPG levels and lipid levels during the third trimester. The final analysis included 1378 participants with complete records. After adjusting for potential confounders, the odds of giving birth to fetal macrosomia were significantly elevated in the overweight or obese pre-pregnancy BMI group (OR = 2.997, 95% CI 1.238-7.258). Receiver operating characteristic (ROC) curve analysis showed that BMI, FPG, triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) had the best-combined prediction effect on macrosomia, and the area under the curve (AUC) was 0.833 (P < 0.05). Chain mediation analysis revealed that FPG and TG jointly mediated the associations between pre-pregnancy BMI and birth weight (BW), BMI, and head circumference, with mediated proportions of 1.96%, 1.84%, and 1.43%, respectively. Additionally, FPG and HDL-C jointly mediated the influence of maternal pre-pregnancy BMI on BW and BMI, with mediated proportions of 1.48% and 3.8%, respectively.

CONCLUSION

The findings of the study indicate that pre-pregnancy BMI is associated with offspring's physical development at birth, with the overweight or obese pre-pregnancy BMI group having an increased risk of macrosomia. The most effective prediction for macrosomia comes from a combination of BMI, FPG, TG, and HDL-C levels. Moreover, the influence of pre-pregnancy BMI on offspring's physical development is partially mediated by FPG, TG, and HDL-C.

WHAT IS KNOWN

• Previous research has established correlations between pre-pregnancy BMI and offspring's physical development. • Previous studies have demonstrated that late pregnancy blood lipid and glucose levels significantly predict fetal physical development.

WHAT IS NEW

• The combination of pre-pregnancy BMI, FPG, TG, and HDL-C is the most effective predictor of macrosomia. • FPG, TG, and HDL-C jointly mediate the effect of pre-pregnancy BMI on physical growth.

Relationship between maternal pre-pregnancy BMI and neonatal birth weight in pregnancies with gestational diabetes mellitus: a retrospective cohort study

Aim

The aim of this study was to explore the association between maternal pre-pregnancy body mass index (BMI) and neonatal birth weight in pregnancies with gestational diabetes mellitus (GDM).

Methods

This was a retrospective cohort study conducted between January 2019 and June 2020 at a university hospital in Fuzhou, China.

Results

Pre-pregnancy BMI was used to categorize 791 pregnant women as underweight (3.03%), normal weight (51.71%), overweight (32.74%), and obese (12.52%). Among the 791 babies, 11.63% were small for gestational age (SGA), 77.37% were normal weight, and 11.00% were large for gestational age (LGA). The rate of the SGA babies increased with higher pre-pregnancy BMI. The percentage of LGA babies was higher in women who were overweight or obese compared to those of normal weight. Neonatal birth weight displayed a significantly increasing trend with increasing maternal pre-pregnancy BMI when maternal pre-pregnancy BMI was less than 27.78 kg/m2 [β = 0.03, 95% CI (0.01, 0.04); p = 0.0052 < 0.05] when maternal pre-pregnancy BMI was greater than 27.78 kg/m2, neonatal birth weight decreased as maternal pre-pregnancy BMI increased [β = -0.01, 95% CI (-0.04, 0.01); p = 0.3555].

Conclusion

The incidence of SGA and LGA babies was higher in the women with GDM who were overweight or obese before pregnancy. The data suggest that different management strategies should be implemented for pregnant women with a pre-pregnancy BMI below 27.78 kg/m2 and above 27.78 kg/m2, particularly in cases of GDM. These findings highlight the importance of providing information, offering preconception counseling, and delivering health education on weight management to ensure healthy pregnancies.

Mediation effect of maternal triglyceride and fasting glucose level on the relationship between maternal overweight/ obesity and fetal growth: a prospective cohort study

BACKGROUND

Previous studies have suggested that maternal overweight/obesity is asscociated with macrosomia. The present study aimed to investigate the mediation effects of fasting plasma glucose (FPG) and maternal triglyceride (mTG) in the relationship between maternal overweight/obesity and large for gestational age (LGA) among non-diabetes pregnant women.

METHODS

This prospective cohort study was conducted in Shenzhen from 2017 to 2021. A total of 19,104 singleton term non-diabetic pregnancies were enrolled form a birth cohort study. FPG and mTG were measured at 24-28 weeks. We analyzed the association of maternal prepregancy overweight/obesity with LGA and mediation effects of FPG and mTG. Multivariable logistic regression analysis and serial multiple mediation analysis were performed. The odds ratio (OR) and 95% confidence intervals (CIs) were calculated.

RESULTS

Mothers who were overweight or obese had higher odds of giving birth to LGA after adjusting potential confounders (OR:1.88, 95%CI: 1.60-2.21; OR:2.72, 95%CI: 1.93-3.84, respectively). The serial multiple mediation analysis found prepregnancy overweight can not only have a direct positive effect on LGA (effect = 0.043, 95% CI: 0.028-0.058), but also have an indirect effect on the LGA through two paths: the independent mediating role of FPG (effect = 0.004, 95% CI: 0.002-0.005); the independent mediating role of mTG (effect = 0.003,95% CI: 0.002-0.005). The chain mediating role of FPG and mTG has no indirect effect. The estimated proportions mediated by FPG and mTG were 7.8% and 5.9%. Besides, the prepregnancy obesity also has a direct effect on LGA (effect = 0.076; 95%CI: 0.037-0.118) and an indirect effect on LGA through three paths: the independent mediating role of FPG (effect = 0.006; 95%CI: 0.004-0.009); the independent mediating role of mTG (effect = 0.006; 95%CI: 0.003-0.008), and the chain mediating role of FPG and mTG (effect = 0.001; 95%CI: 0.000-0.001). The estimated proportions were 6.7%, 6.7%, and 1.1%, respectively.

CONCLUSION

This study found that in nondiabetic women, maternal overweight/obesity was associated with the occurence of LGA, and this positive association was partly mediated by FPG and mTG, suggesting that FPG and mTG in overweight/obese nondiabetic mothers deserve the attention of clinicians.

Umbilical cord blood concentration of connecting peptide (C-peptide) and pregnancy outcomes

Background

C-peptide offers potential as a marker to indicate childhood metabolic outcomes. Measuring C-peptide concentration might have better future utility in the risk stratification of neonates born to overweight or diabetic mothers. Prior research has tried to bring this matter into the light; however, the clinical significance of these associations is still far from reach. Here we sought to investigate the associations between fetomaternal metabolic variables and umbilical cord blood C-peptide concentration.

Methods

For the present study, 858 pregnant women were randomly selected from among a sub-group of 35,430 Iranian pregnant women who participated in a randomized community non-inferiority trial of gestational diabetes mellitus (GDM) screening. Their umbilical cord (UC) blood C-peptide concentrations were measured, and the pregnancy variables of macrosomia/large for gestational age (LGA) and primary cesarean section (CS) delivery were assessed. The variation of C-peptide concentrations among GDM and macrosomia status was plotted. Due to the skewed distribution of C-peptide concentration in the sample, median regression analysis was used to identify potential factors related to UC C-peptide concentration.

Results

In the univariate model, positive GDM status was associated with a 0.3 (95% CI: 0.06 − 0.54, p = 0.01) increase in the median coefficient of UC blood C-peptide concentration. Moreover, one unit (kg) increase in the birth weight was associated with a 0.25 (95% CI: 0.03 − 0.47, p = 0.03) increase in the median coefficient of UC blood C-peptide concentration. In the multivariate model, after adjusting for maternal age, maternal BMI, and macrosomia status, the positive status of GDM and macrosomia were significantly associated with an increase in the median coefficient of UC blood C-peptide concentration (Coef.= 0.27, 95% CI: 0.13 − 0.42, p < 0.001; and Coef.= 0.34, 95% CI: 0.06 − 0.63, p = 0.02, respectively).

Conclusion

UC blood concentration of C-peptide is significantly associated with the incidence of maternal GDM and neonatal macrosomia. Using stratification for maternal BMI and gestational weight gain (GWG) and investigating molecular markers like Leptin and IGF-1 in the future might lay the ground to better understand the link between metabolic disturbances of pregnancy and UC blood C-peptide concentration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05081-4.

Maternal C-Peptide and Insulin Sensitivity, but Not BMI, Associate with Fatty Acids in the First Trimester of Pregnancy

Maternal obesity in pregnancy is a pro-inflammatory condition exposing the fetus to an adverse environment. Here, we tested associations of maternal obesity (primary exposures: BMI, leptin) and metabolic parameters (secondary exposures: glucose, C-peptide, and insulin sensitivity) with total serum concentrations of fatty acids in the first trimester of human pregnancy. This cross-sectional study included 123 non-smoking women with singleton pregnancy. In maternal serum, cotinine, leptin, and C-peptide (ELISA), glucose (hexokinase-based test) and fatty acids (gas chromatography) were quantified, and the insulin sensitivity index (ISHOMA) was calculated. Concentrations of fatty acid classes and total fatty acids did not differ between BMI or leptin categories. However, n-3 polyunsaturated fatty acids (PUFA) were decreased in the category with the highest C-peptide concentration (n-3 PUFA: CI -35.82--6.28, p < 0.006) and in the lowest ISHOMA category (n-3 PUFA: CI -36.48--5.61, p < 0.008). In a subcohort, in which fetal sex was determined (RT-qPCR of placental tissue), C-peptide was significantly associated with docosahexaenoic acid (DHA) in mothers bearing a female (n = 46), but not male (n = 37) fetus. In conclusion, pregnant women with high fasting C-peptide and low ISHOMA had decreased n-3 PUFA, and DHA was lower with higher C-peptide only in mothers bearing a female fetus.

Gestational diabesity and foetoplacental vascular dysfunction

Gestational diabetes mellitus (GDM) shows a deficiency in the metabolism of D-glucose and other nutrients, thereby negatively affecting the foetoplacental vascular endothelium. Maternal hyperglycaemia and hyperinsulinemia play an important role in the aetiology of GDM. A combination of these and other factors predisposes women to developing GDM with pre-pregnancy normal weight, viz. classic GDM. However, women with GDM and prepregnancy obesity (gestational diabesity, GDty) or overweight (GDMow) show a different metabolic status than women with classic GDM. GDty and GDMow are associated with altered l-arginine/nitric oxide and insulin/adenosine axis signalling in the human foetoplacental microvascular and macrovascular endothelium. These alterations differ from those observed in classic GDM. Here, we have reviewed the consequences of GDty and GDMow in the modulation of foetoplacental endothelial cell function, highlighting studies describing the modulation of intracellular pH homeostasis and the potential implications of NO generation and adenosine signalling in GDty-associated foetal vascular insulin resistance. Moreover, with an increase in the rate of obesity in women of childbearing age worldwide, the prevalence of GDty is expected to increase in the next decades. Therefore, we emphasize that women with GDty and GDMow should be characterized with a different metabolic state from that of women with classic GDM to develop a more specific therapeutic approach for protecting the mother and foetus.