Gestational weight gain in Chinese women -- results from a retrospective cohort in Changsha, China

Maternal Height Is an Independent Risk of Adverse Outcomes in Women with Gestational Diabetes Mellitus

INTRODUCTION

Maternal height has been shown to be associated with adverse outcomes in women with gestational diabetes mellitus (GDM). The aim of this study is to evaluate the association between maternal height and adverse outcomes stratified for gestational weight gain (GWG) and pre-pregnancy body mass index (BMI) in women with GDM.

METHODS

We conducted a retrospective study that included 2048 women diagnosed with GDM during 24-28 gestational weeks from July 1, 2017, to June 30, 2018, in Zhejiang Province, China. Demographic data, maternal characteristics and pregnancy complications were extracted from medical records. Maternal height was divided into three categories by tertiles. Chi-square was used to evaluate categorical data while one-way ANOVA was utilized to analyze continuous variables. The relationship between maternal height and adverse outcomes was examined using logistic regression.

RESULTS

We found that shorter women had higher rates of low birth weight (LBW) (p = 0.003) and primary cesarean section (primary CS) (p < 0.001) while taller women had higher rates of abnormal neonatal ponderal index (p < 0.001), postpartum hemorrhage (p = 0.044) and macrosomia (p < 0.001). In taller women who had excess GWG, maternal height was positively associated with the risk of macrosomia (aOR 1.97, 95% CI 0.95-4.10). In shorter women who had inadequate GWG, maternal height was significantly associated with LBW (aOR 2.20, 95% CI 1.13-4.29) and primary CS (aOR 2.08, 95% CI 1.38-3.12). Maternal height was a protective factor of postpartum hemorrhage (aOR 0.15, 95% CI 0.03-0.72) in shorter women with excess GWG. In women with normal pre-pregnancy BMI, maternal height was positively associated with LBW (aOR 2.00, 95% CI 1.15-3.49) and primary CS (aOR 1.71, 95% CI 1.28-2.28) in shorter women while it was negatively associated with the risk of abnormal neonatal ponderal index in both shorter and taller women compared to average height women (aOR 0.71, 95% CI 0.55-0.92; aOR 0.66, 95% CI 0.51-0.85).

CONCLUSION

The association between maternal height and adverse pregnancy outcomes varies with pre-pregnancy BMI and GWG in GDM women. Taking maternal height, pre-pregnancy BMI and GWG into account and using personalized prenatal management may reduce the risk of adverse pregnancy outcomes in GDM.

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.

A prospective analysis of optimal total weight gain ranges and trimester-specific weight gain rates for Chinese pregnant women

BACKGROUND

Gestational weight gain (GWG) criteria recommended by the Institute of Medicine may not be appropriate for Asians. Our aims are to investigate the association between GWG and adverse pregnancy outcomes, and to propose optimal total GWG and rates of GWG for Chinese women.

METHODS

Prospective data of 51,125 mother-child pairs from 27 hospitals and community health care centers from Guizhou, Yunnan and Sichuan provinces in China between 2014 and 2018 were analyzed. Generalized Additive Models were performed to determine the associations of GWG with the risk of aggregated adverse outcomes (gestational diabetes mellitus, preeclampsia, cesarean delivery, stillbirth, preterm birth, macrosomia, large for gestational age, and small for gestational age). The range that did not exceed a 2.5% increase from the lowest risk of aggregated adverse outcomes was defined as the optimal GWG range.

RESULTS

Among all participants, U-shaped prospective association was found between GWG and the risk of aggregated adverse pregnancy outcomes. The optimal GWG range of 8.2-13.0 kg was proposed for underweight, 7.3-12.5 kg for normal weight, and 2.0-9.4 kg for overweight/obese women. Meanwhile, a higher GWG rate in the first two trimesters than that in the last trimester was suggested, except for overweight/obese women. After stratified by maternal age, mothers ≥35 years were suggested to gain less weight compared to younger mothers.

CONCLUSIONS

To keep a balance between maternal health and neonatal growth, optimal GWG ranges based on Asia-specific BMI categories was suggested for Chinese women with different pre-gravid BMIs and maternal ages.

Postpartum weight retention and its association with socio-demographic and obstetrics correlates: A cross-sectional hospital-based preliminary survey in India

BACKGROUND AND AIMS

Postpartum weight retention can predispose women to an elevated risk of obesity and associated complications. The study aims to assess the magnitude of postpartum weight retention and its association with socio-demographic and obstetrics correlates.

METHODS

A cross-sectional survey was carried out in February and March 2022 via telephonic interviews. Convenience sampling technique was used for recruiting postpartum women in first three months, four to six months and beyond six months post-delivery (date of delivery January 2021 to January 2022). Chi² test and regression analysis were employed to study the association of socio-demographic and obstetrics correlates with postpartum weight retention.

RESULTS

The final sample comprised 505 postpartum women with a mean age of 29 ± 4 years. The mean postpartum weight retention was 4.96 ± 3.64 kg, 5.38 ± 3.93 kg and 5.80 ± 3.95 kg in the first three months, four to six months and beyond six months post-delivery respectively. In the first three months, socio-economic status and gestational weight gain were associated with weight retention (p < 0.05). In four-six months, type of family, education qualification, and gestational weight gain were associated with weight retention (p < 0.05). Beyond six months post-delivery, gestational weight gain was associated with postpartum weight retention (p < 0.05).

CONCLUSION

The findings provide preliminary data on the magnitude of weight retention in Indian postpartum women. Postpartum women are at an increased risk of weight retention with the overall shift to a higher body mass index category as compared to the pre-pregnancy period. It is crucial to timely screen women at risk and implement weight management strategies.

Patterns of gestational weight gain among women with obesity and its correlation with hypertensive disorders of pregnancy in Chinese women

Gestational weight management in obese women is critical in clinical work. Adverse pregnancy outcomes are associated with improper gestational weight gain (GWG). However, the pattern of GWG (PGWG) and its correlation with hypertensive disorders of pregnancy (HDP) in obesity are still unclear in China. This retrospective cohort study evaluates clinical data from 799 women through multivariate analyses and trajectory analyses. All the participants are stratified per first trimester weight gain category into three groups (Inadequate-1st, <0.5 kg; Adequate-1st, 0.5-2.0 kg; Excessive-1st, >2.0 kg) and PGWG refers to the weekly weight gain during each gestational period. GWG is positively associated with first trimester weight gain. 78.4% of the Excessive-1st participants have excessive total GWG, in contrast to Inadequate-1st (32.7%) and Adequate-1st (48.2%). After 20 weeks, the weekly weight gain rapidly accelerates, and 77.3% have a weekly weight gain exceeding the Institute of Medicine recommendations. Trajectory analysis of weekly weight gain based on HDP shows two separate weight gain curves after 20 weeks in women with and without a high risk of HDP. Especially in Excessive-1st participants, weekly weight gain after 20 weeks over 0.32 kg/w is positively related to the risk of HDP (<0.32 kg/w vs. 0.32-0.61 kg/w, adjusted odds ratios [aOR]: 2.999, 95% confidence interval [CI]: 1.054-8.537; <0.32 kg/w vs. >0.61 kg/w, aOR: 5.362, 95% CI: 1.719-16.729). In summary, the first trimester is critical for gestational weight management in obesity. Excessive weight gain during the first trimester and after 20 weeks predicts a high risk of HDP, which should be noted in clinical practice.

Weight Gain and Nutrition during Pregnancy: An Analysis of Clinical Practice Guidelines in the Asia-Pacific Region

Nutrition and weight gain during pregnancy can influence the life-course health of offspring. Clinical practice guidelines play an important role in ensuring appropriate nutrition and weight gain among pregnant women. This study aims to identify clinical practice guidelines on gestational weight gain and/or maternal nutrition across the Asia-Pacific region and to determine the quality of the guidelines and variability in the recommendations. Through a systematic search of grey literature from 38 Asia-Pacific countries, 23 published guidelines were obtained. Of these, 10 eligible clinical practice guidelines reporting nutrition- or/and weight-related recommendations for pregnant women were selected and reviewed. Guideline quality was determined using the Assessment of Guidelines for Research Evaluation II (AGREE II) instrument. Of the 10 guidelines, 90% were classified as low-quality in the AGREE II appraisal. Several variations were found with respect to recommendations on gestational weight gain, including those specific to Asian populations. The recommendations on dietary advice, additional energy intake, and nutritional supplementation during pregnancy were varied. Clinical practice guidelines on weight gain and nutrition in pregnancy across the Asia-Pacific region are generally of poor quality, reflecting significant variation, and need to be improved to ensure pregnant women receive appropriate advice. (PROSPERO registration no. CRD42021291395).

Gestational weight gain rates in the first and second trimesters are associated with small for gestational age among underweight women: a prospective birth cohort study

Background

Despite the well-studied effects of gestational weight gain (GWG) on offspring health, little is known about the association of trimester-specific GWG with offspring birth weight among underweight pregnant women. This study aimed to explore the association of trimester-specific GWG rate with small for gestational age (SGA) in underweight women.

Methods

The GWG rate of underweight pregnant women (pre-pregnancy body mass index [BMI] lower than 18.5 kg/m²) of the Born in Guangzhou Cohort Study was calculated as the weight gain during a specific trimester divided by the corresponding duration of week. Total GWG was calculated as the weight difference between pre-pregnancy and delivery, and was categorized into inadequate, adequate, and excessive weight gain based on the 2009 Institute of Medicine (IOM) weight gain recommendation. The INTERGROWTH-21^st standards were used to define SGA. Logistic regression models were used to examine the associations of total GWG and trimester-specific GWG rates with SGA. Associations between trimester-specific GWG rates and SGA were also analyzed separately based on different total GWG categories (i.e. inadequate and adequate/excessive GWG).

Results

Of the 3839 participants, SGA births occurred in 397 (10.3%), and mean GWG was 14.9 kg (SD 3.9). A lower risk of SGA was observed among women with higher GWG rate (per 0.5 kg/week increase) during the first (adjusted OR [aOR] 0.74, 95%CI 0.57, 0.96) and second (adjusted OR [aOR] 0.40, 95%CI 0.30, 0.55) but not third trimester. Similar association between higher GWG rate during the second trimester and a decreased risk of SGA were observed among women with inadequate (< 12.5 kg) and adequate/excessive (≥12.5 kg) total GWG, respectively. Compared to women with adequate GWG rate, women with inadequate GWG rate during the second trimester had a significantly increased risk of SGA (aOR 1.58, 95% CI 1.14, 2.20).

Conclusions

Second-trimester GWG might be the key driver for the association between inadequate GWG and increased risk of SGA births in underweight women.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04433-4.

Gestational weight gain and pregnancy outcomes: Findings from North Indian pregnancy cohort

Despite the high prevalence of inadequate gestational weight gain (GWG) and adverse pregnancy outcomes, very few studies have addressed the association between GWG and pregnancy outcomes in South Asia. Our objectives were to estimate the prevalence of GWG during the second and third trimesters within, below and above the Institute of Medicine (IOM) guidelines, and to estimate the effect of the rate and adequacy of GWG on gestational age at the time of delivery, weight, length, length‐for‐age z‐score (LAZ), weight‐for‐length z‐score (WLZ) and adverse pregnancy outcomes, namely prematurity, small‐for‐gestational age (SGA), low birth weight (LBW), stunting and wasting at birth. We analysed data from the intervention group of the Women and Infants Integrated Interventions for Growth Study (WINGS), which is an ongoing individually randomized factorial design study. Of the 1332 women analysed, 40.2% [95% confidence interval (CI) 37.5 to 42.8] had GWG below the IOM guidelines. For every 100‐g/week increase in GWG, birth weight increased by 61 g, birth length by 0.16 cm, LAZ score by 0.08 SD, WLZ score by 0.14 SD, and gestational age at birth by 0.48 days. Women with GWG below the IOM guidelines had a higher relative risk of adverse pregnancy outcomes (44% for LBW, 27% for SGA, 32% for stunting and 42% for wasting at birth) than women who had GWG within the IOM guidelines, except for prematurity. The association between GWG and LAZ scores at birth was modified by early pregnancy body mass index (BMI). GWG is a strong predictor of newborn anthropometric outcomes and duration of gestation but not prematurity.

Placental mtDNA copy number and methylation in association with macrosomia in healthy pregnancy

INTRODUCTION

Fetal growth and development depend on metabolic energy from placental mitochondria. However, the impact of placental mitochondria on the occurrence of macrosomia remains unclear. We aimed to explore the association between macrosomia without gestational diabetes mellitus (non-GDM) and changes in placental mitochondrial DNA (mtDNA) copy number and methylation.

METHODS

Fifty-four newborns with macrosomia and 54 normal birthweight controls were enrolled in this study. Placental mtDNA copy number and mRNA expression of nuclear genes related to mitochondrial replication or ATP synthesis-related genes were measured by real-time quantitative polymerase chain reaction (qPCR). Methylation levels of the non-coding regulatory region D-loop and ATP synthesis-related genes were detected by targeted bisulfite sequencing.

RESULTS

Newborns with macrosomia had lower placental mtDNA copy number and higher methylation rates of the CpG15 site in the D-loop region (D-CpG15) and CpG6 site in the cytochrome C oxidase III (COX3) gene (COX3-CpG6) than normal birth weight newborns. After adjusting for potential covariates (gestational age, prepregnancy BMI, and infant sex), decreased placental mtDNA copy number (adjusted odds ratio [aOR] = 2.09, 95% confidence interval [CI] 1.03-4.25), elevated methylation rate of D-CpG15 (aOR = 2.06, 95% CI 1.03-4.09) and COX3-CpG6 (aOR = 2.13, 95% CI 1.08-4.20) remained significantly associated with a higher risk of macrosomia.

DISCUSSION

Reduced mtDNA copy number and increased methylation levels of specific loci at mtDNA would increase the risk of macrosomia. However, the detailed molecular mechanism needs further identification.

Optimal gestational weight gain for Chinese women - analysis from a longitudinal cohort with childhood follow-up

BACKGROUND

Maternal gestational weight gain (GWG) influences not only on pregnancy outcome but also impacts on mothers' and children's long-term health. However, there is no consensus on recommendations of optimal GWG in Asians or the Chinese population.

METHODS

We performed a secondary analysis of the birth outcome of Chinese women who had joined the "Hyperglycemia and Adverse Pregnancy Outcome" study in Hong Kong and their children's cardiometabolic risk at 7-year of age. Optimal ranges of GWG were derived from models based on the probabilities of small for gestational age and large for gestational age (model 1), lean and fat infants (model 2) and the integration of model 1 and 2 (model 3), and were compared with that recommended by the Institute of Medicine (IOM) on children's cardiometabolic risk.

FINDINGS

GWG range derived from model 2 is associated with 8 cardiometabolic risk factors, while that from models 1 and 3 are associated with 1 and 7 of them respectively. Mothers whose GWG lie within the recommended range increases from 40.8% according to the IOM recommendation to 50.2% according to that derived from model 2.

INTERPRETATION

Optimal GWG derived from model 2 (i.e. 14.0-18.5 kg, 9.0-16.5 kg and 5.0-11.0 kg for underweight, normal weight and overweight Chinese women, respectively) appeared to be associated with the lowest cardiometabolic risk in the offspring.

FUNDING

General Research Fund of the Research Grants Council of the Hong Kong SAR, China (grants CUHK 473408 and, in part, CUHK 471713).

Short maternal stature and gestational weight gain among refugee and migrant women birthing appropriate for gestational age term newborns: a retrospective cohort on the Myanmar-Thailand border, 2004-2016

Introduction

To examine the interactions between short maternal stature, body mass index (BMI) and gestational weight gain (GWG) among appropriate for gestational age (AGA) term newborns in a population of refugees and migrants in Southeast Asia.

Methods

This is a retrospective cohort study from 2004 to 2016, including women delivering term, singleton newborns, with first trimester height, weight and gestation dated by ultrasound and a last body weight measured within 4 weeks of birth. AGA newborns were those not classified as small for gestational age or large for gestational age by either INTERGROWTH-21st or Gestation Related Optimal Weight standards. The influence of maternal stature on GWG in delivering an AGA newborn was analysed, with GWG compared with existing National Academy of Medicine (NAM) recommendations.

Results

4340 women delivered AGA newborns. Mean maternal height (SD) was 151.5 cm (5.13), with 58.5% of women considered too short by INTERGROWTH-21st standards. Only one in four women (26.5%, 1150/4340) had GWG within NAM recommendations. Women of shorter stature had a significantly lower mean GWG compared with taller women in underweight and normal BMI categories (p<0.001 for both BMI categories). Mean GWG of overweight and obese women did not differ by height (p=1.0 and p=0.85, respectively) and fell within the lower range of NAM recommendations.

Conclusion

These results suggest that short maternal stature can be an important predictor of GWG and should be considered with prepregnancy BMI. Limited-resource settings and special populations need robust GWG recommendations that reflect height and BMI.

Macrosomia and large for gestational age in Asia: One size does not fit all

Macrosomia, usually defined as infant birth weight of ≥4000 g, does not consider gestational age, sex, or country/region-specific differences in mean birth weight and maternal body weight. This issue is particularly relevant for Asia, where 60% of the world's population lives, due to variations in maternal size and birth weights across populations. Large for gestational age (LGA), defined as birth weight > 90th centile, is a more sensitive measure as it considers gestational age and sex, though it is dependent on the choice of growth charts. We aimed to review reporting of macrosomia and LGA in Asia. We reviewed the literature on prevalence and risk of macrosomia and LGA in Asia over the last 29 years. Prevalence of macrosomia ranged from 0.5% (India) to 13.9% (China) while prevalence of LGA ranged from 4.3% (Korea) to 22.1% (China), indicating substantial variation in prevalence within and between Asian countries. High pre-pregnancy body mass index, excessive gestational weight gain, and impaired glucose tolerance conferred risk of macrosomia/LGA. Incidence of macrosomia and LGA varies substantially within and between Asian countries, as do the growth charts and definitions. The latter makes it impossible to make comparisons but suggests differences in intrauterine growth between populations. Reporting LGA, using standardized country/regional growth charts, would better capture the incidence of high birth weight and allow for comparison and identification of contributing factors. Better understanding of local drivers of excessive intrauterine growth could enable development of improved strategies for prevention and management of LGA.

Incidence and trend of preterm birth in China, 1990-2016: a systematic review and meta-analysis

OBJECTIVES

To update the WHO estimate of preterm birth rate in China in 1990-2016 and to further explore variations by geographic regions and years of occurrence.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Pubmed, Embase, Cochrane Library and Sinomed databases were searched from 1990 to 2018.

ELIGIBILITY CRITERIA

Studies were included if they provided preterm birth data with at least 500 total births. Reviews, case-control studies, intervention studies and studies with insufficient information or published before 1990 were excluded. We estimated pooled incidence of preterm birth by a random effects model, and preterm birth rate in different year, region and by livebirths or all births in subgroup analyses.

RESULTS

Our search identified 3945 records. After the removal of duplicates and screening of titles and abstracts, we reviewed 254 studies in full text and excluded 182, leaving 72 new studies. They were combined with the 82 studies included in the WHO report (154 studies, 187 data sets in total for the meta-analysis), including 24 039 084 births from 1990 to 2016. The pooled incidence of preterm birth in China was 6.09% (95% CI 5.86% to 6.31%) but has been steadily increasing from 5.36% (95% CI 4.89% to 5.84%) in 1990-1994 to 7.04% (95% CI 6.09% to 7.99%) in 2015-2016. The annual rate of increase was about 1.05% (95% CI 0.85% to 1.21%). Northwest China appeared to have the highest preterm birth rate (7.3%, 95% CI 4.92% to 9.68% from 1990 to 2016).

CONCLUSIONS

The incidence of preterm birth in China has been rising gradually in the past three decades. It was 7% in 2016. Preterm birth rate varied by region with the West having the highest occurrence.

Optimal Gestational Weight Gain for Tibetans Based on Prepregnancy Body Mass Index

We aimed to estimate the optimal gestational weight gain (GWG) in Tibetan women and to evaluate the appropriateness of the Institute of Medicine (IOM) GWG recommendations for Tibetan women. We analyzed data from 1474 Tibetan women from a cross-sectional study conducted in 2019. According to the three different body mass index (BMI) classification criteria (WHO BMI categories, WHO Asian BMI categories, Chinese BMI categories), we estimated the association of GWG with pregnancy outcomes (neonate birthweight and mode of delivery) using a polynomial regression model, and the optimal GWG in each BMI group was calculated. The risk of adverse outcomes showed a U-shaped curve with increasing GWG. The optimal GWG of Tibetan women based on the WHO BMI categories was 17.2 kg (range, 13.3 to 20.9 kg) for underweight, 9.3 kg (5.8 to 12.9 kg) for normal weight, and 5.2 kg (1.3 to 9.1 kg) for overweight. Underweight Tibetan mothers may gain more gestational weight than recommend by the IOM guidelines. However, normal weight Tibetan mothers are likely to benefit from gaining less weight than that recommended by the IOM. The GWG recommendations based on the IOM guidelines might not be appropriate for Tibetan women, and ethnicity-specific recommendations for GWG should be properly addressed.

Examining the trimester-specific effects of low gestational weight gain on birthweight: the BOSHI study

Low gestational weight gain (GWG) is a known risk factor of low birthweight. Although studies have previously examined the associations between GWG and birthweight, the period-specific effects of low GWG in each trimester remain unclear. This study aimed to quantify the trimester-specific direct effects of low GWG in Japanese women on birthweight. Using perinatal data from a cohort study, we analyzed pregnant women delivered at an obstetrics/gynecology hospital between October 2006 and May 2010. We focused on women with a pre-pregnancy body mass index (BMI) below 25 kg/m2. The exposure was low GWG. The gestation period was subdivided into trimesters, and the direct effects of low trimester-specific GWG on birthweight were estimated using marginal structural models. These models were guided by a direct acyclic graph that incorporated potential confounders, including pre-pregnancy BMI, age, smoking during pregnancy, height, and parity. We analyzed 563 women and their families. The mean cumulative GWG by the end of the first, second, and third trimesters was 0.9, 6.2, and 10.7 kg, respectively. Approximately 14.0% of the women gained total weight below the range recommended by Japanese Ministry of Health, Labour and Welfare. The direct effects of low GWG on birthweight were 65.9 g (95% confidence interval: 11.4, 120.5), -195.4 g (-263.4, -127.4), and -188.8 g (-292.0, -85.5) for the first, second, and third trimesters, respectively. Insufficient weight gain in the second and third trimesters had a negative impact on birthweight after adjusting for pre-pregnancy BMI and other covariates.

Gestational weight gain and risk of autism spectrum disorders in offspring: a systematic review and meta-analysis

It has been revealed that gestational weight gain (GWG) influences the risk of autism spectrum disorder (ASD) in the offspring, but the findings are inconsistent. The current study aimed to evaluate the relationship between GWG and risk of ASD in offspring. Four electronic databases were searched up to August 28 2018 to identify observational studies reporting the association between GWG and risk of ASD in the offspring. Nine studies which met the inclusion criteria were included in the systematic review. Finally, five studies with a total of 3793 children with ASD were included in the meta-analysis. The-results indicated that excessive GWG might increase the risk of ASD in offspring (p = .0008, OR  =  1.23, 95% confidence interval (CI) 1.09-1.38). More high quality cohort studies are needed to confirm this result. This research has the potential to inspire new research on ASD and promote efforts to design appropriate interventions against excessive GWG.Impact statementWhat is already known on this subject? It has been revealed that gestational weight gain (GWG) influences the risk of autism spectrum disorder (ASD) in the offspring, but the findings are inconsistent.What the results of this study add? This is the first systematic review and meta-analysis on the association between GWG and ASDs in offspring. This study suggested that excessive GWG was associated with higher risk of ASD in offspring.What the implications are of these findings for clinical practice and/or further research? More high quality cohort studies are needed to confirm this result. This research has the potential to inspire new research on ASD and promote efforts to design appropriate interventions against excessive GWG.

Application of Japanese guidelines for gestational weight gain to multiple pregnancy outcomes and its optimal range in 101,336 Japanese women

This study was performed to investigate whether the Japanese guidelines for gestational weight gain (GWG) can be used to determine the risks of multiple pregnancy outcomes and estimate optimal GWG in 101,336 women with singleton pregnancies in 2013. Multivariable logistic regression analyses indicated that the risks associated with low birth weight, small for gestational age, and preterm birth increased significantly with weight gain below the Japanese guidelines, and the risks of macrosomia and large for gestational age increased with weight gain above the guidelines regardless of Asian-specific pre-pregnancy body mass index (BMI). The GWG cutoff points estimated from the adjusted area under the receiver operating characteristics curve >0.6 corresponded to 10–13.8 kg in underweight women with pre-pregnancy BMI < 18.5 kg/m²; 10–13.7 kg in normal weight women with pre-pregnancy BMI 18.5–22.9 kg/m²; 8.5–11.4 kg in overweight women with pre-pregnancy BMI 23–24.9 kg/m², 5–13.3 kg in obese women with pre-pregnancy BMI 25–29.9 kg/m²; and 4.7 kg in obese women with pre-pregnancy BMI ≥ 30 kg/m². The optimal GWG ranges proposed by the present study are slightly higher than those recommended by the current Japanese guidelines.

Gestational weight gain and newborn anthropometric outcomes in rural Bangladesh

Low gestational weight gain (GWG) is a known predictor of fetal growth restriction in higher income countries, but there is little information on this association in lower income countries. Our objective is to describe the association between GWG and birth outcomes among pregnant women in rural Bangladesh. Pregnant women were identified in a community-based programme and enrolled into the study at an average of 13 weeks' gestation (n = 4,011). Maternal weight and height were measured at enrolment, maternal weight was measured at 36 weeks' gestation, and newborns were measured after birth. Rate of GWG (g/weeks) was calculated, and women were categorized as having adequate or inadequate GWG (Institute of Medicine recommendations). Newborn anthropometric outcomes included weight-for-age z score (WAZ), length-for-age z score (LAZ), head-circumference-for-age z score (HCZ), body mass index (BMI)-for-age z score (BMIZ), low birthweight (LBW < 2,500 g), WAZ < -2, LAZ < -2, HCZ < -2, BMIZ < -2, and small for gestational age (SGA: <10th percentile). Multivariate models were adjusted for confounders. Only 26% of the 2,562 women in these analyses had adequate GWG. Compared with newborns of women with inadequate GWG, infants of women with adequate GWG had a lower risk of adverse anthropometric outcomes (relative risk [95% confidence interval]: LBW = 0.68 [0.59, 0.80], LAZ < -2 = 0.64 [0.51, 0.80], HCZ < -2 = 0.75 [0.60, 0.93], BMIZ < -2 = 0.70 [0.59, 0.83], and SGA = 0.80 [0.73, 0.86]), but there was no significant difference in mean (SE) duration of gestation, 39.7 (0.08) versus 39.7 (0.05) weeks. In this population, GWG rate is a strong predictor of newborn anthropometric outcomes, but not duration of gestation.

The pattern of gestational weight gains among Chinese women: a repeated measure analysis

This study aimed to investigate the pattern of gestational weight gain (GWG) among Chinese women. We included pregnant women, who delivered at a referral medical center in China and had no pre-specified adverse pregnancy outcomes. We collected weight data across all pregnancy visits, and used the two-level spline linear model to fit for the pattern of GWG according to pre-pregnancy BMI categories. In total, 4,567 pregnant women with 47,699 repeated measures were eligible. For those who were underweight, normal and overweight before pregnancy, the interquartile ranges (25^th to 75^th quartiles) of GWG between 14 and 36 gestational weeks were 12.9–17.7 kg, 12.6–17.3 kg and 11.7–16.8 kg, and the corresponding rates of GWG were 2.62 kg/month, 2.56 kg/month and 2.37 kg/month. For underweight and normal women, the rates of GWG were similar before 14 weeks (0.57 and 0.58 kg/month) and after 36 weeks (1.69 and 1.70 kg/month); however, the rates of GWG were higher for overweight women (0.66 kg/month before 14 weeks and 1.89 kg/month after 36 weeks). In summary, the pattern of GWG among Chinese pregnant women is generally consistent with the IOM recommendation, particularly for those who are normal or underweight. Modifications are, however, warranted for overweight pregnant women.