Comparison of the 2009 Institute of Medicine and 2021 Chinese guidelines for gestational weight gain: A retrospective population-based cohort study.

OBJECTIVE: To analyze the associations between gestational weight gain (GWG) and perinatal outcomes based on the GWG guidelines of the Chinese Nutrition Society (CNS) and the Institute of Medicine (IOM). METHODS: This was a retrospective study with 9075 low-risk singleton pregnant women. Logistic regression model was used to analyze associations between GWG categories and perinatal outcomes. Sensitivity analyses were performed based on pre-pregnancy body mass index (calculated as weight in kilograms divided by the square of height in meters). RESULTS: Excessive GWG as defined by the two guidelines was associated with a higher risk of adverse perinatal outcomes. Inadequate GWG was associated with higher risks of small for gestational age (adjusted odds ratio [aOR] 1.34, 95% confidence interval [CI] 1.10-1.64) and preterm birth (aOR 1.70, 95% CI 1.22-2.36), but a lower risk of large for gestational age (LGA) (aOR 0.77, 95% CI 0.63-0.95) according to the IOM guidelines. When using the CNS guidelines, inadequate GWG was associated with only a lower risk of preterm birth (aOR 1.80, 95% CI 1.19-2.70). Sensitivity analyses suggested that excessive GWG was associated with a higher risk of LGA in underweight women. CONCLUSIONS: Both guidelines could demonstrate the relationship between GWG and adverse perinatal outcomes. The CNS guidelines were more suitable for the Chinese population with underweight or normal weight before pregnancy, whereas IOM was more suitable for pregnant women with inadequate GWG.

Fetal growth velocity references from a Chinese population-based fetal growth study.

BACKGROUND: Fetal growth velocity standards have yet to be established for the Chinese population. This study aimed to establish such standards suitable for the Chinese population. METHODS: We performed a multicenter, population-based longitudinal cohort study including 9075 low-risk singleton pregnant women. Data were collected from the clinical records of 24 hospitals in 18 provinces of China. Demographic characteristics, reproductive history, fetal ultrasound measurements, and perinatal outcome data were collected. The fetal ultrasound measurements included biparietal diameter (BPD), abdominal circumference (AC), head circumference (HC), and femur diaphysis length (FDL). We used linear mixed models with cubic splines to model the trajectory of four ultrasound parameters and estimate fetal weight. Fetal growth velocity was determined by calculating the first derivative of fetal size curves. We also used logistic regression to estimate the association between fetal growth velocities in the bottom 10th percentile and adverse perinatal outcomes. RESULTS: Fetal growth velocity was not consistent over time or among individuals. The estimated fetal weight (EFW) steadily increased beginning at 12 gestational weeks and peaked at 35 gestational weeks. The maximum velocity was 211.71 g/week, and there was a steady decrease in velocity from 35 to 40 gestational weeks. The four ultrasound measurements increased in the early second trimester; BPD and HC peaked at 13 gestational weeks, AC at 14 gestational weeks, and FDL at 15 gestational weeks. BPD and HC also increased from 19 to 24 and 19 to 21 gestational weeks, respectively. EFW velocity in the bottom 10th percentile indicated higher risks of neonatal complications (odds ratio [OR] = 2.23, 95% confidence interval [CI]: 1.79-2.78) and preterm birth < 37 weeks (OR = 3.68, 95% CI: 2.64-5.14). Sensitivity analyses showed that EFW velocity in the bottom 10th percentile was significantly associated with more adverse pregnancy outcomes for appropriate-for-gestational age neonates. CONCLUSIONS: We established fetal growth velocity curves for the Chinese population based on real-world clinical data. Our findings demonstrated that Chinese fetal growth patterns are somewhat different from those of other populations. Fetal growth velocity could provide more information to understand the risk of adverse perinatal outcomes, especially for appropriate-for-gestational age neonates.

Maternal betaine status, but not that of choline or methionine, is inversely associated with infant birth weight.

Maternal one-carbon metabolism during pregnancy is crucial for fetal development and programming by DNA methylation. However, evidence on one-carbon biomarkers other than folate is lacking. We, therefore, investigated whether maternal plasma methyl donors, that is, choline, betaine and methionine, are associated with birth outcomes. Blood samples were obtained from 115 women during gestation (median 26·3 weeks, 90 % range 22·7-33·0 weeks). Plasma choline, betaine, methionine and dimethylglycine were measured using HPLC-tandem MS. Multivariate linear and logistic regression models were used to estimate the association between plasma biomarkers and birth weight, birth length, the risk of small-for-gestational-age and large-for-gestational-age (LGA). Higher level of maternal betaine was associated with lower birth weight (-130·3 (95 % CI -244·8, -15·9) per 1 sd increment for log-transformed betaine). Higher maternal methionine was associated with lower risk of LGA, and adjusted OR, with 95 % CI for 1 sd increase in methionine concentration was 0·44 (95 % CI 0·21, 0·89). Stratified analyses according to infant sex or maternal plasma homocysteine status showed that reduction in birth weight in relation to maternal betaine was only limited to male infants or to who had higher maternal homocysteine status (≥5·1 µmol/l). Higher maternal betaine status was associated with reduced birth weight. Maternal methionine was inversely associated with LGA risk. These findings are needed to be replicated in future larger studies.