Maternal Thyroid Function and Birth Weight in Twins.

CONTEXT: Thyroid hormones are associated with birth weight in singleton pregnancy. Twin pregnancies need more thyroid hormones to maintain the normal growth and development of the fetuses compared with single pregnancy. OBJECTIVE: We aimed to investigate the association of thyroid hormones and birth weight in twins. METHODS: This was a retrospective cohort study in a Chinese population. Pregnant women who received regular antenatal health care and delivered live-born twins from 2014 to 2019 were included (n = 1626). Linear mixed model with restricted cubic splines and logistic regression models were used to estimate the association of thyroid hormones with birth weight and birth weight discordance in twins. RESULTS: We observed that both thyrotropin (TSH) and free thyroxine (FT4) were not associated with birth weight in twins overall, while when stratifying on fetal sex or chorionicity, there were nonlinear association between FT4 levels and birth weight in boys (Pnonlinear < .001) and in dichorionic (DC) twins (Pnonlinear = 0.03). Women with levels of FT4 lower than the 10th percentile had a higher risk of birth weight discordance in their offspring than women with normal FT4 levels (range, 2.5 to 97.5 percentiles) (odds ratio = 1.58; 95% CI, 1.05-2.33). CONCLUSION: Our study suggests there was an association of FT4, but not TSH, with birth weight and birth weight discordance varied by sex and chorionicity. These findings could have implications for obstetricians to be aware of the importance of FT4 levels in preventing birth weight discordance in twin pregnancy.

Response of gut microbiota to serum metabolome changes in intrahepatic cholestasis of pregnant patients.

BACKGROUND: Intrahepatic cholestasis in pregnancy (ICP) is the most common liver disease during pregnancy, and its exact etiology and course of progression are still poorly understood. AIM: To investigate the link between the gut microbiota and serum metabolome in ICP patients. METHODS: In this study, a total of 30 patients were recruited, including 15 patients with ICP (disease group) and 15 healthy pregnant patients (healthy group). The serum nontarget metabolomes from both groups were determined. Amplification of the 16S rRNA V3-V4 region was performed using fecal samples from the disease and healthy groups. By comparing the differences in the microbiota and metabolite compositions between the two groups, the relationship between the gut microbiota and serum metabolites was also investigated. RESULTS: The Kyoto Encyclopedia of Genes and Genomes analysis results showed that the primary bile acid biosynthesis, bile secretion and taurine and hypotaurine metabolism pathways were enriched in the ICP patients compared with the healthy controls. In addition, some pathways related to protein metabolism were also enriched in the ICP patients. The principal coordination analysis results showed that there was a distinct difference in the gut microbiota composition (beta diversity) between the ICP patients and healthy controls. At the phylum level, we observed that the relative abundance of Firmicutes was higher in the healthy group, while Bacteroidetes were enriched in the disease group. At the genus level, most of the bacteria depleted in ICP are able to produce short-chain fatty acids (e.g., Faecalibacterium, Blautia and Eubacterium hallii), while the bacteria enriched in ICP are associated with bile acid metabolism (e.g., Parabacteroides and Bilophila). Our results also showed that specific genera were associated with the serum metabolome. CONCLUSION: Our study showed that the serum metabolome was altered in ICP patients compared to healthy controls, with significant differences in the bile, taurine and hypotaurine metabolite pathways. Alterations in the metabolization of these pathways may lead to disturbances in the gut microbiota, which may further affect the course of progression of ICP.

Prepregnancy Overweight and Obesity Are Associated with an Increased Risk of Preterm Birth in Chinese Women.

INTRODUCTION: The association between obesity before pregnancy and preterm birth varies with age and ethnicity. OBJECTIVE: To study the association between early body mass index (BMI) and risk of preterm birth in Chinese women. METHODS: This was a hospital-based retrospective cohort study including 36,596 Chinese women who gave birth to a live singleton infant from 2015 to 2018. Women were classified as underweight (BMI <18.5), normal weight (BMI 18.5 to <23), overweight (BMI 23 to <27.5), or obese (BMI ≥27.5) according to the most recent criteria for Asian women. Multivariate log-binomial regression models were used to estimate the relative risks (RRs) and 95% confidence intervals (95% CIs) for preterm birth among different groups. RESULTS: Compared to women with normal weight, women with overweight or obesity before pregnancy had an increased risk of preterm birth; the RRs and 95% CIs were 1.22 (95% CI: 1.08-1.37) and 1.30 (95% CI: 1.01-1.69), respectively. The greatest risk of extremely preterm birth was observed in obese women. The estimators were robust when considering the maternal age and rate of gestational weight gain (GWG) during pregnancy. CONCLUSIONS: Women with overweight and obesity had an increased risk of preterm birth regardless of GWG in early pregnancy. Our study suggests that it is beneficial to lose weight before conception for both overweight and obese women who plan to become pregnant.