High Maternal Triglyceride Levels Mediate the Association between Pre-Pregnancy Overweight/Obesity and Macrosomia among Singleton Term Non-Diabetic Pregnancies: A Prospective Cohort Study in Central China

Maternal Obesity Alters Placental and Umbilical Cord Plasma Oxidative Stress, a Cross-Sectional Study

Maternal obesity has been shown to impair the oxidative status in the placenta and newborns, potentially leading to adverse pregnancy outcomes and long-term effects on the programming of offspring metabolic status. This study aimed to investigate the impact of maternal obesity on maternal and umbilical cord plasma oxidative status, as well as placental oxidative adaptation. Maternal obesity (n = 20), defined as a pre-pregnancy BMI ≥ 25 kg/m2, and maternal leanness (n = 20), defined as a pre-pregnancy BMI < 23 kg/m2, were the group categories used in this study. Both groups were matched according to gestational age at delivery. Maternal blood, umbilical cord blood, and placental tissue were collected to assess nutritional content (cholesterol, triglyceride, and protein), oxidative stress markers (MDA and protein carbonyl), and antioxidant activity (SOD and catalase). Placental protein expression (SOD2, catalase, UCP2, and Nrf2) was evaluated using Western blot analysis. Catalase activity in maternal plasma significantly increased in the maternal obesity group (p = 0.0200), with a trend toward increased MDA and protein carbonyl levels. In umbilical cord plasma, triglyceride, protein carbonyl, and catalase activity were significantly elevated in the maternal obesity group compared with the lean controls (p = 0.0482, 0.0291, and 0.0347, respectively). Placental protein expression analysis revealed significantly decreased SOD2 (p = 0.0011) and catalase (p < 0.0001), along with Nrf2 downregulation (p < 0.0001). An increase in mitochondrial antioxidant UCP2 expression was observed (p = 0.0117). The neonatal protein carbonyl levels positively correlated with placental protein carbonyl (r = 0.7405, p < 0.0001) and negatively correlated with maternal catalase activity (r = -0.4332, p = 0.0052). This study thus provides evidence that maternal obesity is associated with placental and fetal oxidative stress, alongside a concurrent increase in placental antioxidant UCP2 expression.

Association between Maternal Body Composition in Second Trimester and Risk of Fetal Macrosomia: A Population-Based Retrospective Study in China

(1) Background: Female body composition undergoes significant changes to support fetal growth and development during pregnancy. This study investigated the association of maternal body composition in the second trimester and macrosomia and explored whether body-composition-related indicators could be used to predict macrosomia. (2) Methods: This study was conducted in China from December 2016 to December 2021. Women with singleton pregnancies, gestational ages between 37 and 42 weeks, and an absence of pregnancy complications were included. In the second trimester, bioelectric impedance analysis (BIA) was used to measure body-composition-related indicators. Logistic regression analysis was performed to explore the risk factors for macrosomia. The predictive performance of maternal body composition and clinical indicators for macrosomia were assessed using the area under the receiver-operating-characteristics curve (AUC). (3) Results: This retrospective study involved 43,020 pregnant women; we collected 2008 cases of macrosomia. Gravidity, gestational age, body mass index (BMI), gestational weight gain (GWG), total body water, fat mass, fat-free mass (FFM), skeletal muscle mass, and visceral fat level were risk factors for macrosomia (p < 0.05 for all). In the prediction model, the AUC of FFM for predicting macrosomia was the largest (0.742). (4) Conclusions: Body-composition-related indicators associated with macrosomia and body composition measurements in the second trimester can predict the risk of macrosomia, enabling clinicians to implement interventions earlier to reduce adverse perinatal outcomes.

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.

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.

Gestational Diabetes Mellitus and High Triglyceride Levels Mediate the Association between Pre-Pregnancy Overweight/Obesity and Macrosomia: A Prospective Cohort Study in Central China

The purpose of this study is to investigate whether the link between pre-pregnancy overweight/obesity and risk of macrosomia is mediated by both gestational diabetes mellitus (GDM) and high maternal triglyceride (mTG) levels. This prospective study finally included 29,415 singleton term pregnancies. The outcome of interest was macrosomia (≥4000 g). High mTG levels were denoted as values ≥90th percentile. GDM was diagnosed using a standard 75 g 2 h oral glucose tolerance test. The mediation analysis was conducted using log-binomial regression while controlling for maternal age, education, parity, gestational weight gain, gestational hypertension, smoking, drinking and infant sex. Overall, 15.9% of pregnant women were diagnosed with GDM, and 4.3% were macrosomia. Mediation analysis suggested that overweight had a total effect of 0.009 (95% CI, 0.006–0.013) on macrosomia, with a direct effect of 0.008 (95% CI, 0.004–0.012) and an indirect effect of 0.001 (95% CI, 0.001–0.002), with an estimated proportion of 11.1% mediated by GDM and high mTG levels together. Furthermore, we also discovered a total effect of obesity on macrosomia of 0.038 (95% CI, 0.030–0.047), consisting of a direct effect of 0.037 (95% CI, 0.028–0.045) and an indirect effect of 0.002 (95% CI, 0.001–0.002), with an estimated proportion of 5.3% mediated by GDM and high mTG levels combined. Both GDM and high mTG levels enhanced the risk of macrosomia independently and served as significant mediators in the relationship between pre-pregnancy overweight/obesity and macrosomia.