Pre-pregnancy body mass index, gestational diabetes mellitus, and gestational weight gain: individual and combined effects on fetal growth.

Background: Pre-pregnancy body mass index (BMI), gestational diabetes mellitus (GDM), and gestational weight gain (GWG) are interlinked and may play a complex role in fetal growth. We aimed to examine the relationship between pre-pregnancy BMI, GDM, GWG, and fetal growth outcomes and explore the contribution of GDM and GWG to the relationship between Pre-pregnancy obesity/overweight and large-for-gestational-age (LGA) in a prospective cohort. Methods: We prospectively recruited women in the first trimester and having one-step GDM screened with a 75-g oral glucose tolerance test between 24 and 28 weeks of gestation (n = 802). Outcomes included LGA, small-for-gestational-age (SGA), and preterm birth. To assess the individual and cumulative associations between pre-pregnancy BMI, GDM, GWG, and these outcomes, we used multivariate logistic regression analysis. Furthermore, we employed structural equation modeling (SEM) to investigate the mediating role of GDM and excessive GWG in the correlation between pre-pregnancy overweight/obesity and LGA. Results: Pre-pregnancy obesity, GDM, and excessive GWG were all independently associated with increased odds of LGA. Inadequate GWG was associated with higher odds of preterm birth. Compared with women unexposed to pre-pregnancy overweight/obesity, GDM, or excessive GWG, women exposed any two conditions had higher odds for LGA (AOR 3.18, 95% CI 1.25-8.11) and women with coexistence of all had the highest odds for LGA (AOR 8.09, 95% CI 2.18-29.97). The mediation analysis showed that GDM explained 18.60% (p < 0.05) of the total effect of pre-pregnancy overweight/obesity on LGA, and GWG explained 17.44% (p < 0.05) of the total effect. Conclusion: Pre-pregnancy obesity/overweight, GDM, and excessive GWG are associated with higher odds of fetal growth disturbances as individual factors and when they co-exist. The effect of pre-pregnancy overweight/obesity on LGA is partially achieved through GDM and excessive GWG.

The association of maternal fat-soluble antioxidants in early pregnancy with gestational diabetes mellitus: a prospective cohort study.

INTRODUCTION: Oxidative stress is linked to the development of gestational diabetes mellitus (GDM). Maternal antioxidant vitamins in early pregnancy may play a role in GDM occurrence. We aimed to investigate the associations of vitamins A and E in early pregnancy with the risk of GDM and to explore whether these antioxidant vitamins can be biomarkers for the early prediction of GDM. METHODS: We carried out a prospective cohort study conducted in Beijing and enrolled pregnant women (n = 667) with vitamins A and E measurements at 9 weeks (IQR 8-10) of gestation and having one-step GDM screened with a 75-g oral glucose tolerance test between 24 and 28 weeks of gestation. RESULTS: The vitamin A levels in early pregnancy were significantly higher in women with GDM than in those without GDM (p < 0.0001) and positively correlated with fasting blood glucose. In multivariate models, vitamin A levels were significantly associated with GDM (OR, 1.46; 95% CI: 1.14-1.88; p = 0.0032) per SD. A significant trend of risk effect on GDM risk across quartiles of vitamin A was observed (ptrend = 0.016). No significant association of serum vitamin E with GDM was observed overall. However, a noted trend of protective effect on GDM risk across quartiles of vitamin E/cholesterol ratio was observed (ptrend = 0.043). In ROC analysis, the multivariate model consisting of vitamin A and other risk factors showed the best predictive performance (AUC: 0.760; 95% CI: 0.705-0.815; p < 0.001). CONCLUSIONS: Higher levels of vitamin A in early pregnancy were significantly associated with an increased risk of GDM. Vitamin A has the potential to be a biomarker indicating pathogenesis of GDM.

Effect of vitamin A on the relationship between maternal thyroid hormones in early pregnancy and fetal growth: A prospective cohort study.

Background: Fetal growth patterns are influenced by maternal thyroid function and vitamin A level during pregnancy. Vitamin A presents interactions with thyroid tissues and hormonal systems. We examined whether vitamin A status modified the associations of maternal thyroid hormones in early pregnancy and fetal growth outcomes among euthyroid pregnant women in a prospective cohort study (n = 637). Methods: We performed multiple linear regression and multinomial logistic regression analysis to investigate the effects of thyroid hormones in early pregnancy on fetal growth according to different levels of serum vitamin A based on median value. Results: A 1 pmol/L increase in maternal free triiodothyronine (FT3) levels was associated with an increased birth weight of 0.080 kg (p = 0.023) in women with lower maternal vitamin A levels in early pregnancy. Increased maternal free thyroxine (FT4) was associated with decreased odds for both small size for gestational age (SGA) [odds ratios (OR) = 0.66, 95% confidence interval (CI): 0.45-0.95] and large size for gestational age (LGA) (OR = 0.66, 95% CI: 0.45-0.98) in women with higher vitamin A level in early pregnancy after adjustment for maternal prepregnancy body mass index, gestational weight gain, maternal employed, parity, gestational week at sampling, and gestational diabetes mellitus. Conclusions: In Chinese pregnant women without overt thyroid dysfunction, maternal FT4 in early pregnancy was positively associated with optimal fetal growth among women with higher serum vitamin A concentrations.