A new recommendation for maternal weight gain in Chinese women

Gestational weight gain and body mass index in Asian Indian women: Impact of timing and amount on fetomaternal outcomes

Background

The aim of the study was to describe pre-pregnancy body mass index (BMI), total gestational weight gain (TGWG), and trimester-specific gestational weight gain (TSGWG) among Asian Indians and examine their association with adverse fetomaternal outcomes (AFMO).

Methods

Using a prospective cohort study design, 557 pregnant women were recruited in the first trimester and followed up until delivery. Maternal BMI, TGWG and TSGWG were assessed and categorised according to the World Health Organisation (WHO) Asia Pacific BMI guidelines and the Institute of Medicine (IOM) recommendations, respectively. Maternal clinical characteristics and pregnancy and neonatal outcomes were assessed to predict AFMO. Logistic regression models in univariate and multivariate analysis were performed to estimate the odds ratios (OR) and 95% confidence intervals (CI).

Results

The median BMI was 23.5 kg/m2. Moreover, 24.6% were overweight and 31.2% were obese, according to WHO Asia Pacific BMI cut points. The mean TGWG was 10.8 ± 1.9 kg and the mean TSGWG in the first, second and third trimesters were 1.7 ± 0.7 kg, 4.3 ± 1.1 kg and 4.8 ± 1.2 kg, respectively. We found a significant association of BMI, TGWG and TSGWG with various AFMO. Furthermore, excess third-trimester GWG has been demonstrated as a predictor of adverse maternal outcomes like hypertension and gestational diabetes mellitus.

Conclusions

Our study reinforces the importance of optimal BMI and TGWG and further emphasises on assessment of TSGWG, which allows for early diagnosis of weight deviations, when prompt interventions can still improve pregnancy outcomes. We also suggest the adoption of BMI categories and GWG recommendations, specific to the socio-demographic characteristics of the population, to optimise the prevention, early diagnosis, and timely management of AFMO.

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.

Gestational weight gain growth charts adapted to Japanese pregnancies using a Bayesian approach in a longitudinal study: The Japan Environment and Children's Study

Background Tracking gestational weight gain (GWG) during pregnancy makes it possible to optimize pregnancy outcomes and GWG growth curves are well suitable for this purpose. The GWG guidelines for Japanese were revised in 2021. However, currently, there are no GWG growth curves to guide women on how to gain weight to meet these guidelines.Methods Using data on 96,631 live births from the Japan Environment and Children's Study (JECS), we created descriptive GWG percentile curves estimated the trajectory of GWG required to meet the GWG guidelines stratified by pre-pregnancy body mass index (BMI) For both analyses, Bayesian mixed models with restricted cubic splines adjusted for maternal characteristics were used.Results GWG curves substantially differed by pre-pregnancy BMI, and were higher among multiparas and those with lower maternal age and with no previous disease. We estimated that underweight, normal weight, overweight and obese women who gain 8.4 to 11.1 kg, 6.4 to 9.1 kg, 3.8 to 6.5 kg, and <1.9 kg at 30 weeks of gestation are on the trajectory to reach the new guidelines at 40 weeks of gestation.Conclusions We provide GWG percentiles curves for Japanese women as well as GWG trajectory curves to meet the new GWG recommendations. These results may help pregnant women monitor weight during their pregnancy.

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.

Determining optimal gestational weight gain (GWG) in a northwest Chinese population: A CONSORT

ABSTRACT

To determine optimal gestational weight gain (GWG) for the Chinese population.Live singleton deliveries at the largest maternal & childcare hospital in northwest China from 2010 to 2012 were analyzed retrospectively. Multivariable logistic regression analysis was conducted to determine the lowest aggregated risk of interested perinatal outcomes based on Chinese adult body mass index (BMI) categories.Eight thousand eight hundred seventy enrolled parturients were divided into 4 groups according to their prepregnancy BMI: underweight (21.31%, BMI < 18.5 kg/m2), normal weight (67.81%, 18.5 kg/m2 ≤ BMI < 24 kg/m2), overweight (8.99%, 24 kg/m2 ≤ BMI < 28 kg/m2 and obese (1.89%, BMI ≥ 28 kg/m2). The optimal GWG values for the above 4 groups were 16.7 kg (GWG range, 12.0-21.5), 14.5 kg (9.5-19.5), 11.5 kg (7.0-16.5), and 8.0 kg (5.0-13.0). The rates of inadequate, optimal and excessive GWG in present study were 6.14% (545), 62.34% (5529), and 31.52% (2796) respectively, which were significantly different from those of the 2009 Institute of Medicine recommendation (χ2 = 1416.05, Pinteraction < 0.0001).Wider optimal GWG ranges than those recommended by Institute of Medicine were found in our study, and our proposed criteria seems to be practical to the Chinese population.

Optimal gestational weight gain in Chinese pregnant women by Chinese-specific BMI categories: a multicentre prospective cohort study

OBJECTIVE

To establish optimal gestational weight gain (GWG) in Chinese pregnant women by Chinese-specific BMI categories and compare the new recommendations with the Institute of Medicine (IOM) 2009 guidelines.

DESIGN

Multicentre, prospective cohort study. Unconditional logistic regression analysis was used to evaluate the OR, 95 % CI and the predicted probabilities of adverse pregnancy outcomes. The optimal GWG range was defined as the range that did not exceed a 1 % increase from the lowest predicted probability in each pre-pregnancy BMI group.

SETTING

From nine cities in mainland China.

PARTICIPANTS

A total of 3731 women with singleton pregnancy were recruited from April 2013 to December 2014.

RESULTS

The optimal GWG (ranges) by Chinese-specific BMI was 15·0 (12·8-17·1), 14·2 (12·1-16·4) and 12·6 (10·4-14·9) kg for underweight, normal weight and overweight pregnant women, respectively. Inappropriate GWG was associated with several adverse pregnancy outcomes. Compared with women gaining weight within our proposed recommendations, women with excessive GWG had higher risk for macrosomia, large for gestational age and caesarean section, whereas those with inadequate GWG had higher risk for low birth weight, small for gestational age and preterm delivery. The comparison between our proposed recommendations and IOM 2009 guidelines showed that our recommendations were comparable with the IOM 2009 guidelines and could well predict the risk of several adverse pregnancy outcomes.

CONCLUSIONS

Inappropriate GWG was associated with higher risk of several adverse pregnancy outcomes. Optimal GWG recommendations proposed in the present study could be applied to Chinese pregnant women.

The role of neonatal vitamin D in the association of prenatal depression with toddlers ADHD symptoms: A birth cohort study

BACKGROUND

Vitamin D has been demonstrated a "neuroprotective" effect, but it is unclear whether early-life adequate vitamin D protect adverse neurodevelopment. We aimed to examine the role of neonatal vitamin D in the association of maternal depression (MD) symptoms with toddlers ADHD.

METHODS

Participants included 1 125 mother-infant pairs from the China-Anhui Birth Cohort study. MD was assessed by the Center for Epidemiological Studies Depression Scale (CES-D) at 30-34 gestational weeks. Toddlers ADHD was reported by the Conners' Hyperactivity Index (CHI) at 48-54 months postpartum. Multiple logistic regression models were performed to evaluate the association of maternal depressive score and toddlers ADHD while cord blood 25(OH)D levels were stratified.

RESULTS

Toddlers of mothers with higher depression score were at higher risk of ADHD (20.1% vs 11.1%, P = 0.003; adjusted RR=1.75, 95% CI: 1.10-2.81). Among toddlers with neonatal vitamin D deficiency (VDD), ADHD risk was significantly increased with maternal MD (adjusted RR=3.74, 95% CI: 1.49-9.41), but the association was not found in toddlers with neonatal vitamin D adequacy (VDA). Compared to toddlers without MD, toddlers with both MD and neonatal VDD had higher risk of ADHD (adjusted RR=3.10, 95% CI: 1.44-6.63). But the risk did not significantly increase in toddlers with MD and neonatal VDA (adjusted RR=1.53, 95% CI: 0.86-2.72).

LIMITATIONS

Maternal depressive symptoms in early pregnancy and anxious symptoms were needed to include.

CONCLUSION

This prospective study indicated that the detrimental effect of maternal prenatal depressive symptoms on offspring's ADHD symptoms strengthened in toddlers with neonatal VDD.

Suggested Gestational Weight Gain for Chinese Women and Comparison with Institute of Medicine Criteria: A Large Population-Based Study

OBJECTIVE

To establish suggested gestational weight gain (GWG) using several distinct methods in a Chinese population.

METHODS

This study analyzed data from the medical records of singleton pregnancy women during 2011-2017 in Beijing, China. Suggested GWG was calculated using four distinct methods. In method 1, suggested GWG was identified by the interquartile method. Subsequently, risk models for small for gestational age (SGA) and large for gestational age (LGA) with respect to GWG were constructed. GWG was treated as a continuous variable in method 2, and as a categorized variable in methods 3 and 4.

RESULTS

An average GWG of 15.78 kg with a prevalence of LGA at 19.34% and SGA at 2.12% was observed among the 34,470 participants. Methods 1 and 2 did not yield clinically applicable results. The suggested GWGs were 11-17/11-16 kg, 9-19/9-15 kg, 4-12/4-10 kg, and 0-12/0-6 kg by method 3/method 4 for underweight, normal-weight, overweight, and obese women, respectively. The GWG range suggested by method 3 resulted in a larger proportion of participants (62.03%) within range, while the suggested GWG range by method 4 was associated with a lower risk of LGA compared to that conferred by the Institute of Medicine (IOM) criteria.

CONCLUSION

This study suggests a modest GWG goal compared to IOM recommendations based on a large Chinese cohort.

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.

Effect of Behavioural Interventions for Obesity Prevention in Pregnancy on the Adequacy of Gestational Weight Gain and Retention: Metabolic Health of Indian Women

The aim of this study was to measure the adequacy of gestational weight gain (GWG) in Indian women using various behavioural interventions during pregnancy, which primarily aim to observe the effects on obesity markers and weight retention.

In this experimental study, one hundred and forty pregnant women underwent interventions in 5 groups, control (C), diet (D), home exercise (HE), supervised exercise (SE) and supervised exercise with diet (SED), from pregnancy through delivery with 2 months follow-up post-delivery. The outcome measures were GWG and baby birth weight.

A one-way ANOVA indicated no differences in the mean GWG between groups (12.39±4.71 kg, p=0.947). The control group had the most (50%) and both the supervised exercise groups had the fewest (32%) women who gained above the recommended GWG, followed by the diet group (33.3%). The D and HE groups had the most women who gained within the GWG range, while both the SE and SED groups had the most women who gained below the GWG range. However, these results did not affect the birth weight between the groups (mean 2.96 kg±0.40, p=0.203). In women with normal BMIs, (18.5-22.9 kg/m2), the diet group had the most effective maintenance of adequate GWG, with 15%, 55%, and 30% of the women gaining above, within, and below the recommended GWG, respectively. The SE and SED groups had the least postpartum weight retention (PPWR) at 2 months, followed by the HM, D and C groups; i.e., the results showed a trend in the desired direction clinically, although they were not statistically significant (p=0.12).

Supervised exercise can be effectively used as a pregnancy intervention to prevent excess GWG in Indian women. Diet counselling was found to be the next best intervention in combination with exercise, as well as for women with normal BMI.

Excessive gestational weight gain in the first trimester is associated with risk of gestational diabetes mellitus: a prospective study from Southwest China

OBJECTIVE

To evaluate the effects of gestational weight gain (GWG) in the first trimester (GWG-F) and the rate of gestational weight gain in the second trimester (RGWG-S) on gestational diabetes mellitus (GDM), exploring the optimal GWG ranges for the avoidance of GDM in Chinese women.

DESIGN

A population-based prospective study was conducted. Gestational weight was measured regularly in every antenatal visit and assessed by the Institute of Medicine (IOM) criteria (2009). GDM was assessed with the 75-g, 2-h oral glucose tolerance test at 24-28 weeks of gestation. Multivariable logistic regression was performed to assess the effects of GWG-F and RGWG-S on GDM, stratified by pre-pregnancy BMI. In each BMI category, the GWG values corresponding to the lowest prevalence of GDM were defined as the optimal GWG range.

SETTING

Southwest China.

PARTICIPANTS

Pregnant women (n 1910) in 2017.

RESULTS

After adjusting for confounders, GWG-F above IOM recommendations increased the risk of GDM (OR; 95 % CI) among underweight (2·500; 1·106, 5·655), normal-weight (1·396; 1·023, 1·906) and overweight/obese women (3·017; 1·118, 8·138) compared with women within IOM recommendations. No significant difference was observed between RGWG-S and GDM (P > 0·05) after adjusting for GWG-F based on the previous model. The optimal GWG-F ranges for the avoidance of GDM were 0·8-1·2, 0·8-1·2 and 0·35-0·70 kg for underweight, normal-weight and overweight/obese women, respectively.

CONCLUSIONS

Excessive GWG in the first trimester, rather than the second trimester, is associated with increased risk of GDM regardless of pre-pregnancy BMI. Obstetricians should provide more pre-emptive guidance in achieving adequate GWG-F.

Optimal gestational weight gain for underweight pregnant women in Japan

We aimed to investigate the optimal range of gestational weight gain (GWG) for Japanese underweight (body mass index <18.5 kg/m²) women using the Japanese Birth Registry System. The study subjects included underweight women who were divided into groups according to the GWG recommendations of the Ministry of Health, Labour and Welfare (MHLW) (9–12 kg): <9.0 kg, group A; 9–12 kg, group B; and >12 kg, group C. The subjects were then classified according to the recommendations of the Institute of Medicine (IOM) (12.7–18.1 kg): <12.7 kg, group D; 12.7–18.1 kg, group E; and >18.1 kg, group F. In total, 148,135 cases were analysed. The frequencies of small for gestational age, preterm delivery, and caesarean delivery were as follows: 19.3%, 22.7%, and 28.5% for group A; 11.7%, 8.7%, and 22.8% for group B; 8.0%, 4.9%, and 21.5% for group C; 15.0%, 14.7%, and 25.2% for group D; 8.0%, 5.3%, and 21.5% for group E; and 7.0%, 5.5%, and 25.0% for group F, respectively. These results indicated that groups C and E had the best outcomes. Therefore, the IOM guidelines seem more appropriate than the MHLW guidelines. Therefore, the MHLW recommended GWG guidelines require revision.

Gestational weight gain charts for different body mass index groups for women in Europe, North America, and Oceania

BACKGROUND

Gestational weight gain differs according to pre-pregnancy body mass index and is related to the risks of adverse maternal and child health outcomes. Gestational weight gain charts for women in different pre-pregnancy body mass index groups enable identification of women and offspring at risk for adverse health outcomes. We aimed to construct gestational weight gain reference charts for underweight, normal weight, overweight, and grades 1, 2 and 3 obese women and to compare these charts with those obtained in women with uncomplicated term pregnancies.

METHODS

We used individual participant data from 218,216 pregnant women participating in 33 cohorts from Europe, North America, and Oceania. Of these women, 9065 (4.2%), 148,697 (68.1%), 42,678 (19.6%), 13,084 (6.0%), 3597 (1.6%), and 1095 (0.5%) were underweight, normal weight, overweight, and grades 1, 2, and 3 obese women, respectively. A total of 138, 517 women from 26 cohorts had pregnancies with no hypertensive or diabetic disorders and with term deliveries of appropriate for gestational age at birth infants. Gestational weight gain charts for underweight, normal weight, overweight, and grade 1, 2, and 3 obese women were derived by the Box-Cox t method using the generalized additive model for location, scale, and shape.

RESULTS

We observed that gestational weight gain strongly differed per maternal pre-pregnancy body mass index group. The median (interquartile range) gestational weight gain at 40 weeks was 14.2 kg (11.4-17.4) for underweight women, 14.5 kg (11.5-17.7) for normal weight women, 13.9 kg (10.1-17.9) for overweight women, and 11.2 kg (7.0-15.7), 8.7 kg (4.3-13.4) and 6.3 kg (1.9-11.1) for grades 1, 2, and 3 obese women, respectively. The rate of weight gain was lower in the first half than in the second half of pregnancy. No differences in the patterns of weight gain were observed between cohorts or countries. Similar weight gain patterns were observed in mothers without pregnancy complications.

CONCLUSIONS

Gestational weight gain patterns are strongly related to pre-pregnancy body mass index. The derived charts can be used to assess gestational weight gain in etiological research and as a monitoring tool for weight gain during pregnancy in clinical practice.

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 (25th to 75th 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.

Gestational weight gain across continents and ethnicity: systematic review and meta-analysis of maternal and infant outcomes in more than one million women

BACKGROUND

The association between Institute of Medicine (IOM) guidelines and pregnancy outcomes across ethnicities is uncertain. We evaluated the associations of gestational weight gain (GWG) outside 2009 IOM guidelines, with maternal and infant outcomes across the USA, western Europe and east Asia, with subgroup analyses in Asia. The aim was to explore ethnic differences in maternal prepregnancy body mass index (BMI), GWG and health outcomes across these regions.

METHODS

Systematic review, meta-analysis and meta-regression of observational studies were used for the study. MEDLINE, MEDLINE In-Process, Embase and all Evidence-Based Medicine (EBM) Reviews were searched from 1999 to 2017. Studies were stratified by prepregnancy BMI category and total pregnancy GWG. Odds ratio (ORs) 95% confidence intervals (CI) applied recommended GWG within each BMI category as the reference. Primary outcomes were small for gestational age (SGA), preterm birth and large for gestational age (LGA). Secondary outcomes were macrosomia, caesarean section and gestational diabetes.

RESULTS

Overall, 5874 studies were identified and 23 were included (n = 1,309,136). Prepregnancy overweight/obesity in the USA, Europe and Asia was measured at 42%, 30% and 10% respectively, with underweight 5%, 3% and 17%. GWG below guidelines in the USA, Europe and Asia was 21%, 18% and 31%, and above was 51%, 51% and 37% respectively. Applying regional BMI categories in Asia showed GWG above guidelines (51%) was similar to that in the USA and Europe. GWG below guidelines was associated with a higher risk of SGA (USA/Europe [OR 1.51; CI 1.39, 1.63]; Asia [1.63; 1.45, 1.82]) and preterm birth (USA/Europe [1.35; 1.17, 1.56]; Asia [1.06; 0.78, 1.44]) than GWG within guidelines. GWG above guidelines was associated with a higher risk of LGA (USA/Europe [1.93; 1.81, 2.06]; Asia [1.68; 1.51 , 1.87]), macrosomia (USA/Europe [1.87; 1.70, 2.06]; Asia [2.18; 1.91, 2.49]) and caesarean (USA/Europe [1.26; 1.21, 1.33]; Asia [1.37; 1.30, 1.45]). Risks remained elevated when regional BMI categories were applied for GWG recommendations. More women in Asia were categorised as having GWG below guidelines using World Health Organization (WHO) (60%) compared to regional BMI categories (16%), yet WHO BMI was not accompanied by increased risks of adverse outcomes.

CONCLUSIONS

Women in the USA and western Europe have higher prepregnancy BMI and higher rates of GWG above guidelines than women in east Asia. However, when using regional BMI categories in east Asia, rates of GWG above guidelines are similar across the three continents. GWG outside guidelines is associated with adverse outcomes across all regions. If regional BMI categories are used in east Asia, IOM guidelines are applicable in the USA, western Europe and east Asia.

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

Background

The generalizability of the gestational weight gain (GWG) ranges recommended by the Institute of Medicine (IOM) to Chinese women is disputed.

Methods

In 2016, 16,780 pregnant women who gave birth to live singletons in Changsha, China, were enrolled. First, subjects with optimal pregnancy outcomes were identified for the GWG percentile distribution description and for comparison to the IOM recommendations. Second, all subjects with optimal GWG according to the IOM body mass index (BMI) cutoffs and those with optimal GWG according to the Asian BMI cutoffs were selected. Pregnancy outcomes were compared between those two groups.

Results

A total of 13,717 births with optimal pregnancy outcomes were selected to describe the GWG distribution. The height and central position of the GWG distributions determined by the Asian BMI cutoffs differed from those determined by the IOM BMI cutoffs among the overweight and obese groups. The recommended IOM GWG ranges were narrower than and shifted to the left of the observed distributions. In both BMI classification schemes, however, the IOM-recommended ranges were within the middle 70% (Pc 15th–85th) and 50% (Pc 25th–75th) of the observed distribution. A total of 6438 (38.37%) and 6110 (36.41%) women gained optimal GWG, according to the IOM and Asian BMI classifications, respectively. Compared with those with optimal GWG according to IOM BMI cutoffs, women with optimal GWG according to the Asian BMI cutoffs had lower risks of both macrosomia (adjusted OR = 0.79, 95%CI: 0.67–0.94) and large-for-gestational age (adjusted OR = 0.86, 95%CI: 0.76, 0.98). However, no significantly different risks of preterm, low birthweight, small-for-gestational age, pregnancy-induced hypertension, or gestational diabetes were found between them.

Conclusions

The IOM-recommended GWG ranges are within the middle 70% of the distributions in Chinese women, and pre-pregnancy weight status should be determined by the Asian BMI cut-off points for monitoring and making GWG recommendations to Chinese women.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1833-y) contains supplementary material, which is available to authorized users.

Current Recommended Vitamin D Prenatal Supplementation and Fetal Growth: Results From the China-Anhui Birth Cohort Study

CONTEXT

Maternal vitamin D insufficiency has been associated with fetal growth restriction. However, the effect of maternal vitamin D supplementation on fetal growth has not been confirmed.

OBJECTIVE

To assess the effect of maternal vitamin D supplementation recommended by the Institute of Medicine (IOM) during pregnancy on the neonatal vitamin D status and the risk of small for gestational age (SGA).

DESIGN AND PARTICIPANTS

As part of the China-Anhui Birth Cohort study, maternal sociodemographic characteristics, food intake, lifestyle, information on vitamin D supplementation, and birth outcomes were prospectively collected. For participants, 600 IU/d of vitamin D3 was routinely advised to take during pregnancy. Cord blood levels of 25-hydroxyvitamin D [25(OH)D], calcium, and phosphorus were measured in 1491 neonates who were divided into three groups based on the duration of maternal vitamin D supplementation during pregnancy.

RESULTS

Mean cord blood concentrations of 25(OH)D were 3.5 nmol/L higher [95% confidence interval (CI), 0.8, 6.2] in neonates (median, 37.9 nmol/L) whose mother took vitamin D supplementation for >2 months during pregnancy compared with those (median, 34.3 nmol/L) whose mother did not take any supplement. These significant differences on cord blood concentrations of 25(OH)D occurred regardless of the season of birth. The adjusted risk of SGA in pregnant women with vitamin D supplementation for >2 months was significantly decreased than that in women without any vitamin D supplementation (11.8% vs 6.9%; adjusted odds ratio = 0.53; 95% CI, 0.32, 0.87).

CONCLUSIONS

The findings from China suggest that maternal vitamin D supplementation recommended by the IOM results in a slight but significantly higher fetal level of 25(OH)D and improves fetal growth.

The Institute of Medicine recommendation for gestational weight gain is probably not optimal among non-American pregnant women: a retrospective study from China

PURPOSE

To investigate whether the Institute of Medicine (IOM) recommended gestational weight gain (GWG) range is optimal among Chinese singleton pregnant women.

METHODS

For the purpose of a retrospective observational study, data on 8209 mature singleton deliveries in Shanghai from January 2014 to December 2016 were extracted from medical records in terms of clinical performance. All cases were categorized as undergainers, appropriate-gainers, and above-gainers according to IOM recommended gestational weight gain range after stratification of maternal BMI and proportions of three categories were calculated. Comparisons of maternal and neonatal outcome were conducted among three categories and the associations of those outcome including risks of low birth weight (LBW) and macrosomia (MAC) with GWG were estimated by logistic regression analysis. To examine the applicability of IOM recommendation for Chinese pregnant women, the accumulated risk of LBW and MAC was displayed by stacked column chart and comparison was made among GWG category. The joint predicted risk (JPR) curve of both LBW and MAC in relation to GWG (continuous measurement) was plotted to demonstrate the relation of lowest JPR corresponding GWG with IOM range.

RESULTS

The IOM recommended weight gain was achieved only by 3502 (42.7%) pregnant women and 41.6% gained excessive weight during pregnancy, especially for the overweight and obese women, the proportions of above-gainers mounting to 65.7 and 75.9%, respectively. By multivariate analysis GWG significantly influenced the risk of MAC and caesarean section. Although the association between the risk of LBW and GWG was not significant, p value reached .051. The risk of delivering macrosomia and caesarean section doubled when GWG exceeded the IOM rang. Appropriate gainers did not always gain the lowest joint risk of low birth weight and macrosomia from stacked column chart and it is obvious that the GWG point according to the lowest JPR was always located left to the IOM recommended range for each BMI category from the JPR curve chart in relation to GWG.

CONCLUSIONS

The IOM recommended GWG range is possibly too much for Chinese singleton pregnant population for each BMI category. It is necessary to build different gestational weight gain standards for specific ethnic population.

Determining optimal gestational weight gain in the Korean population: a retrospective cohort study

BACKGROUND

The World Health Organization (WHO) international body mass index (BMI) cut-off points defining pre-pregnancy BMI categories in the Institute of Medicine (IOM) guidelines are not directly applicable to Asians. We aimed to define the optimal gestational weight gain (GWG) for the Korean population based on Asia-specific BMI categories.

METHODS

Data from 2702 live singleton deliveries in three tertiary centers between 2010 and 2011 were analyzed retrospectively. A multivariable logistic regression analysis was conducted to determine the lowest aggregated risk of composite perinatal outcomes based on Asia-specific BMI categories. The perinatal outcomes included gestational hypertensive disorder, emergency cesarean section, and fetal size for gestational age. In each BMI category, the GWG value corresponding to the lowest aggregated risk was defined as the optimal GWG.

RESULTS

Among the study population, 440 (16.3%) were underweight (BMI < 18.5), 1459 (54.0%) were normal weight (18.5 ≤ BMI < 23), 392 (14.5%) were overweight (23 ≤ BMI < 25) and 411 (15.2%) were obese (BMI ≥ 25). The optimal GWG by Asia-specific BMI category was 20.8 kg (range, 16.7 to 24.7) for underweight, 16.6 kg (11.5 to 21.5) for normal weight, 13.1 kg (8.0 to 17.7) for overweight, and 14.4 kg (7.5 to 21.9) for obese.

CONCLUSION

Considerably higher and wider optimal GWG ranges than recommended by IOM are found in our study in order to avoid adverse perinatal outcomes. Revised IOM recommendations for GWG could be considered for Korean women according to Asian BMI categories. Further prospective studies are needed in order to determine the optimal GWG for the Korean population.

Is it appropriate for Korean women to adopt the 2009 Institute of Medicine recommendations for gestational weight gain?

Background

The 2009 Institute of Medicine (IOM) guidelines for gestational weight gain (GWG) are intended for use among women in the United States. Little data are available on whether the 2009 IOM recommendations can be applied to Asian women. This study aimed to evaluate whether the recommendations are related to adverse pregnancy outcomes in Korean pregnant women.

Methods and findings

A retrospective cohort study was conducted for all singleton-pregnant women at a university hospital in Korea. After classifying the enrolled women into four Korean pre-pregnancy body mass index (BMI) categories, the risk of adverse pregnancy outcomes were analyzed for women who gained inadequate or excessive GWG based on 2009 IOM recommendations. Of 7,843 pregnancies, 64.0% of women had normal pre-pregnancy BMI and 42.7% achieved optimal GWG. Across all BMI categories, adverse pregnancies outcomes such as small for gestational age (SGA), large for gestational age (LGA), preterm birth, preeclampsia, and cesarean due to dystocia were significantly associated with GWG (all P ≤ 0.001).Women with normal BMI who gained inadequate weight were more likely to develop SGA and preterm birth and less likely to develop LGA (adjusted odds ratio (aOR) 2.21, 1.33, and 0.54, respectively). Whereas, women with normal BMI who gained excessive weight were more likely to develop LGA, preterm birth, preeclampsia, and cesarean section due to dystocia (aOR 2.10, 1.33, 1.37, and 1.37, respectively) and less likely to develop SGA (aOR 0.60).

Conclusions

It is tolerable for Korean women to follow recommended GWG from the 2009 IOM guidelines to decrease adverse pregnancy outcomes. This will be helpful for antenatal care on GWG not only for Korean pregnant women, but also other Asian women who have lower BMI criteria than Caucasian women.

Gestational Weight Gain and Pregnancy Outcomes in Relation to Body Mass Index in Asian Indian Women

AIM

The aim of the study was to compare the weight gain during pregnancy (using Institute of Medicine guidelines) among Asian Indians across different body mass index (BMI) categories (using World Health Organization Asia Pacific BMI cut points) and to compare the pregnancy outcomes in each of the different BMI categories.

METHODOLOGY

Retrospective records of 2728 pregnant women attending antenatal clinics and private maternity centers in Chennai, South India, from January 2011 to January 2014 were studied. Pregnancy outcomes were analyzed in relation to BMI and weight gain across different BMI categories.

RESULTS

Overweight and obese women who gained more weight during pregnancy were at high risk of delivering macrosomic infants (overweight - odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.1-5.2, P = 0.02 and obese - OR: 1.6, 95% CI: 1.1-2.4, P = 0.01). In addition, obese women who gained more weight were also at high risk of preterm labor (OR: 2.1, 95% CI: 1.1-3.8; P = 0.01), cesarean section (OR: 1.9, 95% CI: 1.4-2.5; P < 0.001), and preeclampsia (OR: 2.8, 95% CI: 1.1-7.2, P = 0.03). Normal weight and overweight women who gained less weight had a protective effect from cesarean section and macrosomia.

CONCLUSIONS

Overweight/obese women who gained more weight than recommended are at a high risk of developing adverse pregnancy outcomes. Normal and overweight women who gained weight less than recommended have low risk for cesarean section and macrosomia. However, they have a higher (statistically insignificant) risk for low birth weight and preterm birth. This highlights the need for gaining adequate weight during pregnancy.

Association of Female Reproductive Factors with Hypertension, Diabetes and LQTc in Chinese Women

The association of female reproductive factors (FRFs) with cardiovascular risk factors among different population was variable and inconsistent. The objective of this study was to examine the association between FRFs and hypertension, type 2 diabetes mellitus (DM), and long heart-rate-corrected QT interval (LQTc) in Chinese post-menopausal women (Post-MW). A total of 8046 Post-MW from the China Chaoshan Biobank Cohort Study were included for analysis. Logistic regression and general linear regression models were used to estimate the association between FRFs and hypertension, DM, and LQTc. Compared with women with 0 or 1 live birth, increasing risk of hypertension (odds ratio [OR], 1.51; 95% confidence interval [CI], 1.16-1.96), DM (OR, 1.65; 95% CI, 1.22-2.22), and LQTc (OR, 1.45; 95% CI, 1.01-2.09) were observed in women who had five or more live births. Further analysis demonstrated that the association between parity and hypertension, DM, and LQTc was mediated by lifestyle and dyslipidemia. Women with more live births had increased body mass index and waist circumstance, and were inclined to consume more salty food, animal fat, and alcohol, but less meat, vegetable, fish, plant oil, and tea, compared with that had fewer live births (all P < 0.05).

Small-for-gestational age and its association with maternal blood glucose, body mass index and stature: a perinatal cohort study among Chinese women

OBJECTIVE

To examine whether maternal low blood glucose (BG), low body mass index (BMI) and small stature have a joint effect on the risk of delivery of a small-for-gestational age (SGA) infant.

DESIGN

Women from a perinatal cohort were followed up from receiving perinatal healthcare to giving birth.

SETTING

Beichen District, Tianjin, China between June 2011 and October 2012.

PARTICIPANTS

1572 women aged 19-39 years with valid values of stature, BMI and BG level at gestational diabetes mellitus screening (gestational weeks 24-28), glucose challenge test <7.8 mmol/L and singleton birth (≥37 weeks' gestation).

MAIN OUTCOME MEASURES

SGA was defined as birth weight <10th centile for gender separated gestational age of Tianjin singletons.

RESULTS

164 neonates (10.4%) were identified as SGA. From multiple logistic regression models, the ORs (95% CI) of delivery of SGA were 0.84 (0.72 to 0.98), 0.61 (0.49 to 0.74) and 0.64 (0.54 to 0.76) for every 1 SD increase in maternal BG, BMI and stature, respectively. When dichotomises, maternal BG (<6.0 vs ≥6.0 mmol/L), BMI (<24 vs ≥24 kg/m(2)) and stature (<160.0 vs ≥160.0 cm), those with BG, BMI and stature all in the lower categories had ∼8 times higher odds of delivering an SGA neonate (OR (95% CI) 8.01 (3.78 to 16.96)) relative to the reference that had BG, BMI and stature all in the high categories. The odds for an SGA delivery among women who had any 2 variables in the lower categories were ∼2-4 times higher.

CONCLUSIONS

Low maternal BG is associated with an increased risk of having an SGA infant. The risk of SGA is significantly increased when the mother is also short and has a low BMI. This may be a useful clinical tool to identify women at higher risk for having an SGA infant at delivery.

Systematic Review of the Methodological Quality of Studies Aimed at Creating Gestational Weight Gain Charts

A range of adverse outcomes is associated with insufficient and excessive maternal weight gain in pregnancy, but there is no consensus regarding what constitutes optimal gestational weight gain (GWG). Differences in the methodological quality of GWG studies may explain the varying chart recommendations. The goal of this systematic review was to evaluate the methodological quality of studies that aimed to create GWG charts by scoring them against a set of predefined, independently agreed-upon criteria. These criteria were divided into 3 domains: study design (12 criteria), statistical methods (7 criteria), and reporting methods (4 criteria). The criteria were broken down further into items, and studies were assigned a quality score (QS) based on these criteria. For each item, studies were scored as either high (score = 0) or low (score = 1) risk of bias; a high QS correlated with a low risk of bias. The maximum possible QS was 34. The systematic search identified 12 eligible studies involving 2,268,556 women from 9 countries; their QSs ranged from 9 (26%) to 29 (85%) (median, 18; 53%). The most common sources for bias were found in study designs (i.e., not prospective); assessments of prepregnancy weight and gestational age; descriptions of weighing protocols; sample size calculations; and the multiple measurements taken at each visit. There is wide variation in the methodological quality of GWG studies constructing charts. High-quality studies are needed to guide future clinical recommendations. We recommend the following main requirements for future studies: prospective design, reliable evaluation of prepregnancy weight and gestational age, detailed description of measurement procedures and protocols, description of sample-size calculation, and the creation of smooth centile charts or z scores.

Gestational weight gain standards based on women enrolled in the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project: a prospective longitudinal cohort study

OBJECTIVE

To describe patterns in maternal gestational weight gain (GWG) in healthy pregnancies with good maternal and perinatal outcomes.

DESIGN

Prospective longitudinal observational study.

SETTING

Eight geographically diverse urban regions in Brazil, China, India, Italy, Kenya, Oman, United Kingdom, and United States, April 2009 to March 2014.

PARTICIPANTS

Healthy, well nourished, and educated women enrolled in the Fetal Growth Longitudinal Study component of the INTERGROWTH-21(st) Project, who had a body mass index (BMI) of 18.50-24.99 in the first trimester of pregnancy.

MAIN OUTCOME MEASURES

Maternal weight measured with standardised methods and identical equipment every five weeks (plus/minus one week) from the first antenatal visit (<14 weeks' gestation) to delivery. After confirmation that data from the study sites could be pooled, a multilevel, linear regression analysis accounting for repeated measures, adjusted for gestational age, was applied to produce the GWG values.

RESULTS

13,108 pregnant women at <14 weeks' gestation were screened, and 4607 met the eligibility criteria, provided consent, and were enrolled. The variance within sites (59.6%) was six times higher than the variance between sites (9.6%). The mean GWGs were 1.64 kg, 2.86 kg, 2.86 kg, 2.59 kg, and 2.56 kg for the gestational age windows 14-18(+6) weeks, 19-23(+6) weeks, 24-28(+6) weeks, 29-33(+6) weeks, and 34-40(+0) weeks, respectively. Total mean weight gain at 40 weeks' gestation was 13.7 (SD 4.5) kg for 3097 eligible women with a normal BMI in the first trimester. Of all the weight measurements, 71.7% (10,639/14,846) and 94.9% (14,085/14,846) fell within the expected 1 SD and 2 SD thresholds, respectively. Data were used to determine fitted 3rd, 10th, 25th, 50th, 75th, 90th, and 97th smoothed GWG centiles by exact week of gestation, with equations for the mean and standard deviation to calculate any desired centiles according to gestational age in exact weeks.

CONCLUSIONS

Weight gain in pregnancy is similar across the eight populations studied. Therefore, the standards generated in this study of healthy, well nourished women may be used to guide recommendations on optimal gestational weight gain worldwide.

Parity and Risk of Stroke among Chinese Women: Cross-sectional Evidence from the Dongfeng-Tongji Cohort Study

Epidemiological studies have investigated the association between parity and the risk of stroke, but the results have been inconsistent. The objective of this study was to assess the association among middle-aged and older Chinese women. We used data from the Dongfeng-Tongji Cohort Study. In total, 14,277 women were included in the analysis. Participants were classified into four groups according to parity. Stroke cases were self-reported during face-to-face interviews. Multivariable logistic regression models were used to investigate the association between parity and the risk of stroke while controlling for potential confounders. The prevalence of stroke among the study subjects was 2.7% (380 of 14,277). In the fully adjusted model, women who had experienced two, three, or four or more live births had 1.24 times (95% CI, 0.85-1.81), 1.97 times (95% CI, 1.30-2.98) and 1.86 times (95% CI, 1.14-3.03), higher risk of stroke, respectively, compared with women who had experienced one live birth. High parity was associated with an increasing risk of stroke in the present study. Further longitudinal studies are needed to confirm the association and to explore the unclear mechanism underlying the link between parity and stroke risk.

Childbearing May Increase the Risk of Nondiabetic Cataract in Chinese Women's Old Age

Backgrounds. Ocular changes may arise during pregnancy and after childbirth, but very few studies have reported the association between childbearing and cataract among older adults. Methods. 14,292 individuals aged 60+ years were recruited in Xiamen, China, in 2013. Physician-diagnosed cataract and diabetes status were assessed by a self-reported questionnaire. Childbearing status was measured by number of children (NOC). Structural equation modeling (SEM) analysis was conducted to examine the relationships among NOC, diabetes, and cataract. Gender-specific logistic models regressing nondiabetic cataract on NOC were performed by adjusting some covariates. Results. 14,119 participants had complete data, of whom 5.01% suffered from cataract, with higher prevalence in women than men (6.41% versus 3.51%). Estimates of SEM models for women suggested that both NOC and diabetes were risk factors for cataract and that no correlation existed between NOC and diabetes. Women who had one or more children faced roughly 2–4 times higher risk of nondiabetic cataract than their childless counterparts (OR [95% CI] = 3.88 [1.24, 17.71], 3.21 [1.04, 14.52], 4.32 [1.42, 19.44], 4.41 [1.46, 19.74], and 3.98 [1.28, 18.10] for having 1, 2, 3, 4-5, and 6 or more children, resp.). Conclusions. Childbearing may increase the risk of nondiabetic cataract in Chinese women's older age.

Pre-Pregnancy Body Mass Index, Gestational Weight Gain, and Birth Weight: A Cohort Study in China

Objective

To assess whether pre-pregnancy body mass index (BMI) modify the relationship between gestational weight gain (GWG) and child birth weight (specifically, presence or absence of low birth weight (LBW) or presence of absence of macrosomia), and estimates of the relative risk of macrosomia and LBW based on pre-pregnancy BMI were controlled in Wuhan, China.

Methods

From June 30, 2011 to June 30, 2013. All data was collected and available from the perinatal health care system. Logistic regression models were used to estimate the independent association among pregnancy weight gain, LBW, normal birth weight, and macrosomia within different pre-pregnancy BMI groups. We built different logistic models for the 2009 Institute of Medicine (IOM) Guidelines and Chinese-recommended GWG which was made from this sample. The Chinese-recommended GWG was derived from the quartile values (25th-75th percentiles) of weight gain at the time of delivery in the subjects which comprised our sample.

Results

For LBW children, using the recommended weight gain of the IOM and Chinese women as a reference, the OR for a pregnancy weight gain below recommendations resulted in a positive relationship for lean and normal weight women, but not for overweight and obese women. For macrosomia, considering the IOM’s recommended weight gain as a reference, the OR magnitude for pregnancy weight gain above recommendations resulted in a positive correlation for all women. The OR for a pregnancy weight gain below recommendations resulted in a negative relationship for normal BMI and lean women, but not for overweight and obese women based on the IOM recommendations, significant based on the recommended pregnancy weight gain for Chinese women. Of normal weight children, 56.6% were above the GWG based on IOM recommendations, but 26.97% of normal weight children were above the GWG based on Chinese recommendations.

Conclusions

A GWG above IOM recommendations might not be helpful for Chinese women. We need unified criteria to classify adult BMI and to expand the sample size to improve representation and to elucidate the relationship between GWG and related outcomes for developing a Chinese GWG recommendation.

Diet or exercise, or both, for preventing excessive weight gain in pregnancy

BACKGROUND

This is an update of a Cochrane review first published in 2012, Issue 4. Excessive weight gain during pregnancy is associated with poor maternal and neonatal outcomes including gestational diabetes, hypertension, caesarean section, macrosomia, and stillbirth. Diet or exercise interventions, or both, may reduce excessive gestational weight gain (GWG) and associated poor outcomes; however, evidence from the original review was inconclusive.

OBJECTIVES

To evaluate the effectiveness of diet or exercise, or both, interventions for preventing excessive weight gain during pregnancy and associated pregnancy complications.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (5 November 2014), contacted investigators of the previously identified ongoing studies and scanned reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of diet or exercise, or both, interventions for preventing excessive weight gain in pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We organised RCTs according to the type of interventions and pooled data using the random-effects model in the Review Manager software. We also performed subgroup analyses according to the initial risk of adverse effects related to poor weight control. We performed sensitivity analysis to assess the robustness of the findings.

MAIN RESULTS

We included 65 RCTs, out of which 49 RCTs involving 11,444 women contributed data to quantitative meta-analysis. Twenty studies were at moderate-to-high risk of bias. Study interventions involved mainly diet only, exercise only, and combined diet and exercise interventions, usually compared with standard care. Study methods varied widely; therefore, we estimated the average effect across studies and performed sensitivity analysis, where appropriate, by excluding outliers and studies at high risk of bias.Diet or exercise, or both, interventions reduced the risk of excessive GWG on average by 20% overall (average risk ratio (RR) 0.80, 95% confidence interval (CI) 0.73 to 0.87; participants = 7096; studies = 24; I² = 52%). This estimate was robust to sensitivity analysis, which reduced heterogeneity, therefore we graded this evidence as high-quality. Interventions involving low glycaemic load diets, supervised or unsupervised exercise only, or diet and exercise combined all led to similar reductions in the number of women gaining excessive weight in pregnancy.Women receiving diet or exercise, or both interventions were more likely to experience low GWG than those in control groups (average RR 1.14, 95% CI 1.02 to 1.27; participants = 4422; studies = 11; I² = 3%; moderate-quality evidence). We found no difference between intervention and control groups with regard to pre-eclampsia (RR 0.95, 95% CI 0.77 to 1.16; participants = 5330; studies = 15; I² = 0%; high-quality evidence); however, maternal hypertension (not a pre-specified outcome) was reduced in the intervention group compared with the control group overall (average RR 0.70, 95% CI 0.51 to 0.96; participants = 5162; studies = 11; I² = 43%; low-quality evidence).There was no clear difference between groups with regard to caesarean delivery overall (RR 0.95, 95% CI 0.88 to 1.03; participants = 7534; studies = 28; I² = 9%; high-quality evidence); although the effect estimate suggested a small difference (5%) in favour of the interventions. In addition, for combined diet and exercise counselling interventions there was a 13% (-1% to 25%) reduction in this outcome (borderline statistical significance).We found no difference between groups with regard to preterm birth overall (average RR 0.91, 95% CI 0.68 to 1.22; participants = 5923; studies = 16; I² = 16%; moderate-quality evidence); however limited evidence suggested that these effect estimates may differ according to the types of interventions, with a trend towards an increased risk for exercise-only interventions.We found no clear difference between intervention and control groups with regard to infant macrosomia (average RR 0.93, 95% CI 0.86 to 1.02; participants = 8598; studies = 27; I² = 0%; high-quality evidence), although the effect estimate suggested a small difference (7% reduction) in favour of the intervention group. The largest effect size occurred in the supervised exercise-only intervention group (RR 0.81, 95% CI 0.64 to 1.02; participants = 2445; studies = 7; I² = 0%), which approached statistical significance (P = 0.07). Furthermore, in subgroup analysis by risk, high-risk women (overweight or obese women, or women with or at risk of gestational diabetes) receiving combined diet and exercise counselling interventions experienced a 15% reduced risk of infant macrosomia (average RR 0.85, 95% CI 0.73 to 1.00; participants = 3252; studies = nine; I² = 0; P = 0.05; moderate-quality evidence)There were no differences in the risk of poor neonatal outcomes including shoulder dystocia, neonatal hypoglycaemia, hyperbilirubinaemia, or birth trauma (all moderate-quality evidence) between intervention and control groups; however, infants of high-risk women had a reduced risk of respiratory distress syndrome if their mothers were in the intervention group (RR 0.47, 95% CI 0.26 to 0.85; participants = 2256; studies = two; I² = 0%; moderate-quality evidence).

AUTHORS' CONCLUSIONS

High-quality evidence indicates that diet or exercise, or both, during pregnancy can reduce the risk of excessive GWG. Other benefits may include a lower risk of caesarean delivery, macrosomia, and neonatal respiratory morbidity, particularly for high-risk women receiving combined diet and exercise interventions. Maternal hypertension may also be reduced. Exercise appears to be an important part of controlling weight gain in pregnancy and more research is needed to establish safe guidelines. Most included studies were carried out in developed countries and it is not clear whether these results are widely applicable to lower income settings.

Parity and the risk of diabetes mellitus among Chinese women: a cross-sectional evidence from the Tongji-Dongfeng cohort study

Objectives

Little is known about the long-term health impact of pregnancy on women. The objective of this study was to examine the association between parity and the risk of diabetes among a population of Chinese women.

Study design

A total of 14,196 women (aged ≥45 years) from the Dongfeng-Tongji Cohort study who had experienced at least one live birth completed baseline questionnaires, medical examinations, and provided baseline blood samples. Participants were categorized into four groups according to parity (one, two, three, or four or more live births). Logistic regression models were used to investigate the association between parity and the risk of diabetes after controlling potential confounders.

Results

The prevalence of diabetes in the study population was 18.0% (2,552/14,196). Fasting plasma glucose levels increased with the increasing number of live births (P<0.001) and parity had a positive graded association with diabetes without adjustment for any covariates (P for trend <0.001). After adjusting for potential confounders, women who had had two, three, and four or more live births had 1.35 times (95% CI, 1.20–1.52), 1.59 times (95% CI, 1.39–1.82) and 1.44 times (95% CI, 1.21–1.71), respectively, higher risk of diabetes compared with women who had had one live birth.

Conclusion

Multiparity was associated with increasing risk of diabetes in this population of Chinese women. These findings suggested that multiparity may be a risk factor for the development of diabetes among Chinese women. Future studies are needed to examine the physiological changes during pregnancy for risk of diabetes in later life.

Determining optimal gestational weight gain in a multiethnic Asian population

AIM

To define the optimal gestational weight gain (GWG) for the multiethnic Singaporean population.

METHODS

Data from 1529 live singleton deliveries was analyzed. A multinomial logistic regression analysis, with GWG as the predictor, was conducted to determine the lowest aggregated risk of a composite perinatal outcome, stratified by Asia-specific body mass index (BMI) categories. The composite perinatal outcome, based on a combination of delivery type (cesarean section [CS], vaginal delivery [VD]) and size for gestational age (small [SGA], appropriate [AGA], large [LGA]), had six categories: (i) VD with LGA; (ii) VD with SGA; (iii) CS with AGA; (iv) CS with SGA; (v) CS with LGA; (vi) and VD with AGA. The last was considered as the 'normal' reference category. In each BMI category, the GWG value corresponding to the lowest aggregated risk was defined as the optimal GWG, and the GWG values at which the aggregated risk did not exceed a 5% increase from the lowest aggregated risk were defined as the margins of the optimal GWG range.

RESULTS

The optimal GWG by pre-pregnancy BMI category, was 19.5 kg (range, 12.9 to 23.9) for underweight, 13.7 kg (7.7 to 18.8) for normal weight, 7.9 kg (2.6 to 14.0) for overweight and 1.8 kg (-5.0 to 7.0) for obese.

CONCLUSION

The results of this study, the first to determine optimal GWG in the multiethnic Singaporean population, concur with the Institute of Medicine (IOM) guidelines in that GWG among Asian women who are heavier prior to pregnancy, especially those who are obese, should be lower. However, the optimal GWG for underweight and obese women was outside the IOM recommended range.

A longitudinal study of weight gain in pregnancy in Malawi: unconditional and conditional standards

BACKGROUND

To monitor weight gain during pregnancy and assess its relation with perinatal health outcomes, both unconditional (cross-sectional) and conditional (longitudinal) standards of maternal weight are needed.

OBJECTIVE

This study aimed to develop and validate unconditional and conditional maternal weight standards for use in Malawi, Africa.

DESIGN

Longitudinal data were drawn from an antenatal care intervention study conducted in Malawi. Participants were selected for this analysis if they had a healthy profile defined by body mass index and infectious disease measures and delivered healthy singletons defined by birth weight, gestational age, and neonatal survival status. A total of 1733 measurements from 358 women were randomly split to form development and validation samples.

RESULTS

Unconditional and conditional standards were developed and validated. An electronic spreadsheet implements the calculations. Weight gain during pregnancy was substantially slower in this cohort than the US Institute of Medicine recommendation. The percentiles increased linearly; therefore, the use of the conditional standards is robust to inaccuracy in gestational age estimates.

CONCLUSION

The standards can facilitate researchers and clinicians to examine maternal weight and weight gain and estimate their associations with pregnancy outcomes in Malawi. This trial was registered at www.clinicaltrials.gov as NCT00131235.

Interventions for preventing excessive weight gain during pregnancy

BACKGROUND

Excessive weight gain during pregnancy is associated with multiple maternal and neonatal complications. However, interventions to prevent excessive weight gain during pregnancy have not been adequately evaluated.

OBJECTIVES

To evaluate the effectiveness of interventions for preventing excessive weight gain during pregnancy and associated pregnancy complications.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (20 October 2011) and MEDLINE (1966 to 20 October 2011).

SELECTION CRITERIA

All randomised controlled trials and quasi-randomised trials of interventions for preventing excessive weight gain during pregnancy.

DATA COLLECTION AND ANALYSIS

We assessed for inclusion all potential studies we identified as a result of the search strategy. At least two review authors independently assessed trial quality and extracted data. We resolved discrepancies through discussion. We have presented results using risk ratio (RR) for categorical data and mean difference for continuous data. We analysed data using a fixed-effect model.

MAIN RESULTS

We included 28 studies involving 3976 women; 27 of these studies with 3964 women contributed data to the analyses. Interventions focused on a broad range of interventions. However, for most outcomes we could not combine data in a meta-analysis, and where we did pool data, no more than two or three studies could be combined for a particular intervention and outcome. Overall, results from this review were mainly not statistically significant, and where there did appear to be differences between intervention and control groups, results were not consistent. For women in general clinic populations one (behavioural counselling versus standard care) of three interventions examined was associated with a reduction in the rate of excessive weight gain (RR 0.72, 95% confidence interval 0.54 to 0.95); for women in high-risk groups no intervention appeared to reduce excess weight gain. There were inconsistent results for mean weight gain (reported in all but one of the included studies). We found a statistically significant effect on mean weight gain for five interventions in the general population and for two interventions in high-risk groups.Most studies did not show statistically significant effects on maternal complications, and none reported significant effects on adverse neonatal outcomes.

AUTHORS' CONCLUSIONS

There is not enough evidence to recommend any intervention for preventing excessive weight gain during pregnancy, due to the significant methodological limitations of included studies and the small observed effect sizes. More high-quality randomised controlled trials with adequate sample sizes are required to evaluate the effectiveness of potential interventions.

Post-partum weight retention in women in Asia: a systematic review

Obesity is a health issue for people in Asia, and many studies support that childbearing may contribute to women's obesity. However, most studies of post-partum weight retention (PWR) focus on Western countries. This paper aimed to review recent data on PWR and discuss the related factors of PWR for women in Asia. Three electronic databases - MEDLINE, CINAHL and PsycINFO - were searched for data from January 1990 to August 2010. Twelve studies were identified as containing information related to PWR. Chinese, Taiwanese and Korean women tend to have higher gestational weight gain and PWR than women in other Asian countries in this review. The average reported gestational weight gain in these studies ranged from 8.3 kg to 18.0 kg, and the average weight retention at 6 months post partum in various countries ranged from 1.56 kg to 4.1 kg. Gestational weight gain had a positive effect on PWR, but there were no consistent conclusions for other factors. Only a few psychosocial and behavioural factors have been studied. Moreover, no one has assessed changes in waist circumference and waist-to-hip ratio for measuring central obesity and ensuring risk of chronic disease. Focusing on changes in maternal weight and body composition, and considering the impact of psychological and behavioural factors are suggested for future studies in Asia.

Low gestational weight gain and the risk of preterm birth and low birthweight: a systematic review and meta-analyses

BACKGROUND

Low gestational weight gain is common, with potential adverse perinatal outcomes.

OBJECTIVE

To determine the relation between low gestational weight gain and preterm birth and low birthweight in singletons in developing and developed countries.

DATA SOURCES

Medline, EMBASE and reference lists were searched, identifying 6,283 titles and abstracts.

METHODS OF STUDY SELECTION

Following the MOOSE consensus statement, two assessors independently reviewed titles, abstracts, full articles, extracted data and assessed quality.

RESULTS

Fifty-five studies, 37 cohort and 18 case-control, were included, involving 3,467,638 women. In the cohort studies (crude data, generally supported where available by adjusted data and case-control studies), women with low total gestational weight gain had increases in preterm birth <37 weeks [RR 1.64 (95%CI 1.62-1.65)], 32-36 weeks [RR 1.39 (95%CI 1.38-1.40)] and ≤ 32 weeks [RR 3.80 (95%CI 3.72-3.88)]. Low total gestational weight gain was associated with increased risks of low birthweight <2,500 g [RR 1.85 (95%CI 1.72-2.00)], in developing and developed countries [RR 1.84 (95%CI 1.71-1.99) and RR 3.02 (95%CI 1.37-6.63), respectively], 1,500-2,500 g [RR 2.02 (95%CI 1.88-2.17)] and <1,500 g (RR 2.00 (95%CI 1.67-2.40)]. Women with low weekly gestational weight gain were at increased risk of preterm birth [RR 1.56 (95%CI 1.26-1.94)], 32-36 weeks [RR 2.43 (95%CI 2.37-2.50)] and ≤ 32 weeks [RR 2.31 (95%CI 2.20-2.42)] but not low birthweight [RR 1.64 (95%CI 0.89-3.02)].

CONCLUSIONS

In this systematic review, we determined that singletons born to women with low total gestational weight gain have higher risks of preterm birth and low birthweight, with the lower the gain, the higher the risks.

Optimal gestational weight gain ranges for the avoidance of adverse birth weight outcomes: a novel approach

BACKGROUND

Gestational weight gain (GWG) has been shown to be directly associated with birth weight.

OBJECTIVE

We aimed to define ranges for optimal GWG with respect to the risk of either small- or large-for-gestational-age offspring by using a new statistical approach.

DESIGN

For the purpose of an observational study, data on n = 177,079 mature singleton deliveries in Bavaria between 2004 and 2006 were extracted from a standard data set that is regularly collected for national benchmarking of obstetric units in terms of clinical performance. Joint predicted risks of either small- or large-for-gestational-age births in relation to GWG (continuous measurement) were estimated by logistic regression models with adjustment for potential confounders.

RESULTS

The estimated optimal GWG ranges as defined by a joint predicted risk of <or=20% were substantially wider than those recommended by the Institute of Medicine for underweight (8-25 compared with 12.5-18.0 kg) and normal-weight (2-18 compared with 11.5-16.0 kg) women. Overweight and obese women's optimal GWG ranged from -7 to 12 and -15 to 2 kg, respectively (Institute of Medicine recommendations: 7.0-11.5 and 5.0-9.0 kg, respectively). We observed considerable effect modifications by parity and smoking in pregnancy. In normal-weight primiparae, for example, the optimal GWG range was 10-26 kg for nonsmokers compared with 23-27 kg for smokers.

CONCLUSIONS

Considerably wider optimal GWG ranges than recommended by the Institute of Medicine might be tolerated with respect to avoidance of adverse birth weight outcome. Stratification by maternal body mass index category alone might not be sufficient.

The performance of various anthropometric assessment methods for predicting low birth weight in pregnant women

OBJECTIVES: to assess the performance of various anthropometric methods for the evaulation of the nutritional status of pregnant women as a means of predicting low birth weight (LBW). METHODS: a descriptive cross-cutting study carried out among 433 pregnant women (>20 years) attending a Public Maternity Hospital in Rio de Janeiro, Brazil. The adequacy of the weight gain at the end of the pregnancy was evaluated in accordance with the proposals of the Institute of Medicine and the Brazilian Ministry of Health. The sensitivity, specificity and accuracy of the adequacy of weight gain at the end of the pregnancy or nutritional state of mother as a predictor of low birth weight were calculated. RESULTS: the sensitivity of the various methods varied from 63.1% to 68.4% and the specificity from 71.2% to 75.1%. The adapted Institute of Medicine proposal drawn up by the Brazilian Ministry of Health, according to the classification of the pre-delivery nutritional status of the mother according to the World Health Organization cutoff points showed itself to be the most accurate (74.5%), this being the most adequate method for nutritional triage for reason of its association with low birth weight (OR=4.10; 95%CI=1.53-10.92). CONCLUSIONS: the best proposals for this population are those of the Institute of Medicine and the Brazilian Ministry of Health. Further studies aiming to ascertain the most appropriate methods of anthropometric evaluation for different populations should be encouraged.

Reference charts for weight gain and body mass index during pregnancy obtained from a healthy cohort

OBJECTIVE

To create reference charts for weight gain and body mass index (BMI) in pregnancy derived from longitudinal data obtained in a representative sample of the Argentinean population.

METHODS

A prospective cohort of 1439 healthy pregnant women was selected from antenatal clinics in seven different urban regions in Argentina. Serial anthropometric measurements were made at weeks 12, 16, 20, 24, 28, 32, 36 and in the last pre-natal control. Centile curves of body weight and BMI by gestational age were developed using the LMS method.

RESULTS

Mean weight gain at 38 weeks of gestation was 11.9 +/- 4.4 kg. There were no differences in total weight gain between women who enter pregnancy with low, normal or overweight; only those women with a pre-pregnancy BMI in the range of obesity showed a significantly lower weight gain (10.2 +/- 4.8 kg). At 12 weeks of pregnancy, BMI values of the 10th, 50th and 90th centiles were 19.3, 22.8 and 29.0, and at 38 weeks these values were 23.3, 27.4 and 33.8, respectively.

CONCLUSION

This BMI for gestational age chart, based on women who delivered normal birth weight infants and processed with modern statistical methods, represents an improvement in pre-natal care monitoring.

Achieving a healthy weight gain during pregnancy

This review uses the 1990 U.S. Institute of Medicine (IOM) gestational weight gain recommendations to examine the question, what is a healthy pregnancy weight gain? The relationship of gestational weight gain to infant size at birth; pregnancy, labor, and delivery complications; neonatal, infant, and child outcomes; and maternal weight and health outcomes in U.S. and European populations are discussed. Pregnancy weight gains within the IOM recommendations are associated with better outcomes. The possible exception is very obese women, who may benefit from weight gains less than the 7 kg (15 pounds) recommended. Only about 33% to 40% of U.S. women gain within IOM recommendations. Excessive gestational weight gain is more prevalent than inadequate gain. Women's gestational weight gains tend to follow the recommendations of health care providers. Current interventions demonstrate efficacy in influencing gestational weight gain in low-income women with normal and overweight body mass index in the United States and obese women in Scandinavia.

Optimal Gestational Weight Gain for Body Mass Index Categories

OBJECTIVE

To establish optimal gestational weight gain for each maternal body mass index (BMI) category based on significant risk estimates of adverse maternal and fetal outcome.

METHODS

The study population consisted of 298,648 singleton pregnancies delivered in Sweden between January 1, 1994, and December 31, 2004. The number of individuals in each weight gain class was compared with the number of individuals in all other weight gain classes in the same BMI group with regard to adverse maternal and fetal outcome. Odds ratios were calculated after suitable adjustments.

RESULTS

The optimal gestational weight gain in women by prepregnancy BMI was 9-22 lb (4-10 kg) for BMI less than 20; 5-22 lb (2-10 kg) for BMI 20-24.9; less than 20 lb (less than 9 kg) for BMI 25-29.9; and less than 13 lb (less than 6 kg) for BMI of 30 or more.

CONCLUSION

The gestational weight gain limits for BMI categories determined in this large population-based cohort study from Swedish Medical Registers showed that a decreased risk of adverse obstetric and neonatal outcomes was associated with lower gestational weight gain limits than was earlier recommended, especially among obese women.

Self-reported experiences of racial discrimination and Black-White differences in preterm and low-birthweight deliveries: the CARDIA Study

OBJECTIVES

We examined the effects of self-reported experiences of racial discrimination on Black-White differences in preterm (less than 37 weeks gestation) and low-birthweight (less than 2500 g) deliveries.

METHODS

Using logistic regression models, we analyzed data on 352 births among women enrolled in the Coronary Artery Risk Development in Young Adults Study.

RESULTS

Among Black women, 50% of those with preterm deliveries and 61% of those with low-birthweight infants reported having experienced racial discrimination in at least 3 situations; among White women, the corresponding percentages were 5% and 0%. The unadjusted odds ratio for preterm delivery among Black versus White women was 2.54 (95% confidence interval [CI]=1.33, 4.85), but this value decreased to 1.88 (95% CI=0.85, 4.12) after adjustment for experiences of racial discrimination and to 1.11 (95% CI=0.51, 2.41) after additional adjustment for alcohol and tobacco use, depression, education, and income. The corresponding odds ratios for low birthweight were 4.24 (95% CI=1.31, 13.67), 2.11 (95% CI=0.75, 5.93), and 2.43 (95% CI=0.79, 7.42).

CONCLUSIONS

Self-reported experiences of racial discrimination were associated with preterm and low-birthweight deliveries, and such experiences may contribute to Black-White disparities in perinatal outcomes.

Low preconception body mass index is associated with birth outcome in a prospective cohort of Chinese women

Low maternal prepregnancy BMI is associated with adverse birth outcomes, but the BMI at which risk increases is not well defined. We assessed whether the relationship between prepregnancy BMI and birth outcomes is influenced by the extent to which mothers were underweight in a prospective study in Anhui, China. The women (n = 575) were 20-34 y old, married, nulliparous and nonsmokers. All measures of infant growth increased with increasing maternal BMI until a plateau was reached at a BMI of 22-23 kg/m2. Infants born to the 27% of women who were severely underweight before pregnancy (BMI < or = 18.5 kg/m2) were at increased risk for fetal growth deficits associated with infant morbidity. Compared with a normal BMI, being severely underweight was associated with mean (+/- SEM) reductions of 219 +/- 40 g in infant birthweight and 6.7 +/- 1.3% in the birthweight ratio and an 80% increase in risk of intrauterine growth restriction [odds ratio (OR) 1.8; 95% CI: 1.0, 3.3; P = 0.05]. Being severely underweight was also associated with smaller infant head circumference and lower ponderal index. Being moderately underweight (18.5 < BMI < 19.8 kg/m2) was not significantly associated with adverse pregnancy outcomes. Gestational age and risk of preterm birth were not associated with maternal BMI. More than half of the women in this study were underweight before pregnancy. Although being moderately underweight was not associated with increased risk of adverse pregnancy outcomes, being severely underweight was an important risk factor for reduced fetal growth.

Position of the American Dietetic Association: nutrition and lifestyle for a healthy pregnancy outcome

It is the position of the American Dietetic Association that women of childbearing potential should maintain good nutritional status through a lifestyle that optimizes maternal health and reduces the risk of birth defects, suboptimal fetal growth and development, and chronic health problems in their children. The key components of a health-promoting lifestyle during pregnancy include appropriate weight gain; consumption of a variety of foods in accordance with the Food Guide Pyramid; appropriate and timely vitamin and mineral supplementation; avoidance of alcohol, tobacco, and other harmful substances; and safe food-handling. Prenatal weight gain within the Institute of Medicine (IOM) recommended ranges is associated with better pregnancy outcomes. The total energy needs during pregnancy range between 2,500 to 2,700 kcal a day for most women, but prepregnancy body mass index, rate of weight gain, maternal age, and physiological appetite must be considered in tailoring this recommendation to the individual. The consumption of more food to meet energy needs and the increased absorption and efficiency of nutrient utilization that occurs in pregnancy are generally adequate to meet the needs for most nutrients. However, vitamin and mineral supplementation is appropriate for some nutrients and situations. This statement also includes recommendations pertaining to use of alcohol, tobacco, caffeine, street drugs, and other substances during pregnancy; food safety; and management of common complaints during pregnancy and specific health problems. In particular for medical nutrition therapy, pregnant women with inappropriate weight gain, hyperemesis, poor dietary patterns, phenylketonuria (PKU), certain chronic health problems, or a history of substance abuse should be referred to a qualified dietetics professional.