High Gestational Weight Gain and the Risk of Preterm Birth and Low Birth Weight: A Systematic Review and Meta-Analysis

The interaction between PAX9 rs2073244 and passive smoking during pregnancy on low birth weight in newborns: a case-control study

To explore whether rs2073244 at PAX9 increased susceptibility for full-term low birth weight infants and whether indoors passive smoking exposure has a combined effect with rs2073244 on newborn low birth weight (LBW), a 1:2 paired case-control study of LBW newborns was conducted at Xiamen University Affiliated Women and Children's Hospital from March 2010 to October 2013. The rate of indoor passive smoking exposure in the LBW group was higher than it in the NBW group (p = 0.019). GG of PAX9 rs2073244 decreased the risk of LBW [OR = 0.38, 95% CI: (0.15-0.98)] and smaller HC [OR = 0.44, 95% CI:(0.20-0.98)]. The relative excess risk for LBW contributed by the additive interaction between the rs2073244 risk genotypes AG/AA and mother pregnancy passive smoking exposure was 10.679 (95%CI 1.728-65.975). Our study suggested that the AG/AA genotype of PAX9 rs2073244 might be a risk factor for LBW of full-term newborns, especially in maternal passive smoking.

Pre-pregnancy BMI, rate of gestational weight gain, and preterm birth among US Pacific Islander individuals

OBJECTIVE

The objective of this study was to examine the association between rate of gestational weight gain (GWG) and preterm birth (PTB) classified by pre-pregnancy BMI among Pacific Islander individuals in the United States.

METHODS

Pacific Islander mothers (n = 55,975) and singleton infants (22-41 gestational weeks) without congenital anomalies were included using data from the National Center for Health Statistics (2014-2018). PTB was compared by pre-pregnancy BMI among women in each stratum of rate of GWG using Cox proportional hazards models.

RESULTS

Compared with mothers with a rate of GWG within the guidelines, mothers with a rate of GWG below the guidelines and either pre-pregnancy underweight (adjusted hazard ratio [aHR] = 1.84, 95% CI: 1.10-3.06), healthy weight (aHR = 1.38, 95% CI: 1.15-1.65), obesity class I (aHR = 1.22, 95% CI: 0.97-1.52), or obesity class II (aHR = 1.43, 95% CI: 1.05-1.96) had an increased risk of PTB; mothers with a rate of GWG above the guidelines and either pre-pregnancy underweight (aHR = 1.57, 95% CI: 0.92-2.69) or obesity class II (aHR = 1.31, 95% CI: 0.98-1.76) had an increased risk of PTB.

CONCLUSIONS

The association between rate of GWG below or above the guidelines and PTB differs by pre-pregnancy BMI among Pacific Islander individuals.

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

Background

Pre-pregnancy body mass index (BMI), gestational diabetes mellitus (GDM), and gestational weight gain (GWG) are interlinked and may play a complex role in fetal growth. We aimed to examine the relationship between pre-pregnancy BMI, GDM, GWG, and fetal growth outcomes and explore the contribution of GDM and GWG to the relationship between Pre-pregnancy obesity/overweight and large-for-gestational-age (LGA) in a prospective cohort.

Methods

We prospectively recruited women in the first trimester and having one-step GDM screened with a 75-g oral glucose tolerance test between 24 and 28 weeks of gestation (n = 802). Outcomes included LGA, small-for-gestational-age (SGA), and preterm birth. To assess the individual and cumulative associations between pre-pregnancy BMI, GDM, GWG, and these outcomes, we used multivariate logistic regression analysis. Furthermore, we employed structural equation modeling (SEM) to investigate the mediating role of GDM and excessive GWG in the correlation between pre-pregnancy overweight/obesity and LGA.

Results

Pre-pregnancy obesity, GDM, and excessive GWG were all independently associated with increased odds of LGA. Inadequate GWG was associated with higher odds of preterm birth. Compared with women unexposed to pre-pregnancy overweight/obesity, GDM, or excessive GWG, women exposed any two conditions had higher odds for LGA (AOR 3.18, 95% CI 1.25-8.11) and women with coexistence of all had the highest odds for LGA (AOR 8.09, 95% CI 2.18-29.97). The mediation analysis showed that GDM explained 18.60% (p < 0.05) of the total effect of pre-pregnancy overweight/obesity on LGA, and GWG explained 17.44% (p < 0.05) of the total effect.

Conclusion

Pre-pregnancy obesity/overweight, GDM, and excessive GWG are associated with higher odds of fetal growth disturbances as individual factors and when they co-exist. The effect of pre-pregnancy overweight/obesity on LGA is partially achieved through GDM and excessive GWG.

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.

Risk factors for preterm birth: an umbrella review of meta-analyses of observational studies

BACKGROUND

Preterm birth defined as delivery before 37 gestational weeks is a leading cause of neonatal and infant morbidity and mortality. The aim of this study is to summarize the evidence from meta-analyses of observational studies on risk factors associated with PTB, evaluate whether there are indications of biases in this literature, and identify which of the previously reported associations are supported by robust evidence.

METHODS

We searched PubMed and Scopus until February 2021, in order to identify meta-analyses examining associations between risk factors and PTB. For each meta-analysis, we estimated the summary effect size, the 95% confidence interval, the 95% prediction interval, the between-study heterogeneity, evidence of small-study effects, and evidence of excess-significance bias. Evidence was graded as robust, highly suggestive, suggestive, and weak.

RESULTS

Eighty-five eligible meta-analyses were identified, which included 1480 primary studies providing data on 166 associations, covering a wide range of comorbid diseases, obstetric and medical history, drugs, exposure to environmental agents, infections, and vaccines. Ninety-nine (59.3%) associations were significant at P < 0.05, while 41 (24.7%) were significant at P < 10-6. Ninety-one (54.8%) associations had large or very large heterogeneity. Evidence for small-study effects and excess significance bias was found in 37 (22.3%) and 12 (7.2%) associations, respectively. We evaluated all associations according to prespecified criteria. Seven risk factors provided robust evidence: amphetamine exposure, isolated single umbilical artery, maternal personality disorder, sleep-disordered breathing (SDB), prior induced termination of pregnancy with vacuum aspiration (I-TOP with VA), low gestational weight gain (GWG), and interpregnancy interval (IPI) following miscarriage < 6 months.

CONCLUSIONS

The results from the synthesis of observational studies suggest that seven risk factors for PTB are supported by robust evidence. Routine screening for sleep quality and mental health is currently lacking from prenatal visits and should be introduced. This assessment can promote the development and training of prediction models using robust risk factors that could improve risk stratification and guide cost-effective preventive strategies.

TRIAL REGISTRATION

PROSPERO 2021 CRD42021227296.

Suboptimal gestational weight gain and neonatal outcomes in low and middle income countries: individual participant data meta-analysis

OBJECTIVE

To estimate the associations between gestational weight gain (GWG) during pregnancy and neonatal outcomes in low and middle income countries.

DESIGN

Individual participant data meta-analysis.

SETTING

Prospective pregnancy studies from 24 low and middle income countries.

MAIN OUTCOME MEASURES

Nine neonatal outcomes related to timing (preterm birth) and anthropometry (weight, length, and head circumference) at birth, stillbirths, and neonatal death.

ANALYSIS METHODS

A systematic search was conducted in PubMed, Embase, and Web of Science which identified 53 prospective pregnancy studies published after the year 2000 with data on GWG, timing and anthropometry at birth, and neonatal mortality. GWG adequacy was defined as the ratio of the observed maternal weight gain over the recommended weight gain based on the Institute of Medicine body mass index specific guidelines, which are derived from data in high income settings, and the INTERGROWTH-21st GWG standards. Study specific estimates, adjusted for confounders, were generated and then pooled using random effects meta-analysis models. Maternal age and body mass index before pregnancy were examined as potential modifiers of the associations between GWG adequacy and neonatal outcomes.

RESULTS

Overall, 55% of participants had severely inadequate (<70%) or moderately inadequate (70% to <90%) GWG, 22% had adequate GWG (90-125%), and 23% had excessive GWG (≥125%). Severely inadequate GWG was associated with a higher risk of low birthweight (adjusted relative risk 1.62, 95% confidence interval 1.51 to 1.72; 48 studies, 93 337 participants; τ2=0.006), small for gestational age (1.44, 1.36 to 1.54; 51 studies, 93 191 participants; τ2=0.016), short for gestational age (1.47, 1.29 to 1.69; 40 studies, 83 827 participants; τ2=0.074), and microcephaly (1.57, 1.31 to 1.88; 31 studies, 80 046 participants; τ2=0.145) compared with adequate GWG. Excessive GWG was associated with a higher risk of preterm birth (1.22, 1.13 to 1.31; 48 studies, 103 762 participants; τ2=0.008), large for gestational age (1.44, 1.33 to 1.57; 47 studies, 90 044 participants; τ2=0.009), and macrosomia (1.52, 1.33 to 1.73; 29 studies, 68 138 participants; τ2=0) compared with adequate GWG. The direction and magnitude of the associations between GWG adequacy and several neonatal outcomes were modified by maternal age and body mass index before pregnancy.

CONCLUSIONS

Inadequate and excessive GWG are associated with a higher risk of adverse neonatal outcomes across settings. Interventions to promote optimal GWG during pregnancy are likely to reduce the burden of adverse neonatal outcomes, however further research is needed to assess optimal ranges of GWG based on data from low and middle income countries.

Risk factors for preterm labor: An Umbrella Review of meta-analyses of observational studies

Preterm birth defined as delivery before 37 gestational weeks, is a leading cause of neonatal and infant morbidity and mortality. Understanding its multifactorial nature may improve prediction, prevention and the clinical management. We performed an umbrella review to summarize the evidence from meta-analyses of observational studies on risks factors associated with PTB, evaluate whether there are indications of biases in this literature and identify which of the previously reported associations are supported by robust evidence. We included 1511 primary studies providing data on 170 associations, covering a wide range of comorbid diseases, obstetric and medical history, drugs, exposure to environmental agents, infections and vaccines. Only seven risk factors provided robust evidence. The results from synthesis of observational studies suggests that sleep quality and mental health, risk factors with robust evidence should be routinely screened in clinical practice, should be tested in large randomized trial. Identification of risk factors with robust evidence will promote the development and training of prediction models that could improve public health, in a way that offers new perspectives in health professionals.

Gestational Weight Gain and Birth Outcome: A Comparison of Methods of Accounting for Gestational Age

Cross-sectional studies of total gestational weight gain (GWG) and perinatal outcomes have used different approaches to operationalize GWG and adjust for duration of gestation. Using birth records from California (2007-2017), Nevada (2010-2017), and Oregon (2008-2017), we compared 3 commonly used approaches to estimate associations between GWG and cesarean delivery, small-for-gestational-age birth, and low birth weight (LBW): 1) the Institute of Medicine-recommended GWG ranges at a given gestational week, 2) total weight gain categories directly adjusting for gestational age as a covariate, and 3) weight-gain-for-gestational-age z scores derived from an external longitudinal reference population. Among 5,461,130 births, the 3 methods yielded similar conclusions for cesarean delivery and small-for-gestational-age birth. However, for LBW, some associations based on z scores were in the opposite direction of methods 1 and 2, paradoxically suggesting that higher GWG increases risk of LBW. This was due to a greater proportion of preterm births among those with high z scores, and controlling for gestational age in the z score model brought the results in line with the other methods. We conclude that the use of externally derived GWG z scores based on ongoing pregnancies can yield associations confounded by duration of pregnancy when the outcome is strongly associated with gestational age at delivery.

Gestational weight gain during the second and third trimesters and adverse pregnancy outcomes, results from a prospective pregnancy cohort in urban Tanzania

BACKGROUND

Appropriate gestational weight gain (GWG) is important for optimal pregnancy outcomes. This study prospectively evaluated the associations between GWG during the second and third trimesters of pregnancy and adverse pregnancy outcomes in an urban Tanzanian pregnancy cohort.

METHODS

We used data from a randomized clinical trial conducted among pregnant women recruited by 27 weeks of gestation in Dar es Salaam, Tanzania (N = 1230). Women's gestational weight was measured at baseline and at monthly antenatal visits. Weekly GWG rate during the second and third trimesters was calculated and characterized as inadequate, adequate, or excessive, in conjunction with measured or imputed early-pregnancy BMI status according to the 2009 Institute of Medicine (IOM) GWG guidelines. We used multivariable Poisson regression with a sandwich variance estimator to calculate risk ratios (RR) for associations of GWG with low birth weight, preterm birth, small for gestational age (SGA), and large for gestational age (LGA). Degree of appropriate GWG defined using additional metrics (i.e., percentage of adequacy, z-score) and potential effect modification by maternal BMI were additionally evaluated.

RESULTS

According to the IOM guidelines, 517 (42.0%), 270 (22.0%), and 443 (36.0%) women were characterized as having inadequate, adequate, and excessive GWG, respectively. Overall, compared to women with adequate GWG, women with inadequate GWG had a lower risk of LGA births (RR = 0.54, 95% CI: 0.36-0.80) and a higher risk of SGA births (RR = 1.32, 95% CI: 0.95-1.81). Women with inadequate GWG as defined by percentage of GWG adequacy had a higher risk of LBW (OR = 1.93, 95% CI: 1.03-3.63). In stratified analyses by early-pregnancy BMI, excessive GWG among women with normal BMI was associated with a higher risk of preterm birth (RR = 1.59, 95% CI: 1.03-2.44).

CONCLUSIONS

A comparatively high percentage of excessive GWG was observed among healthy pregnant women in Tanzania. Both inadequate and excessive GWGs were associated with elevated risks of poor pregnancy outcomes. Future studies among diverse SSA populations are warranted to confirm our findings, and clinical recommendations on optimal GWG should be developed to promote healthy GWG in SSA settings.

TRIAL REGISTRATION

This trial was registered as "Prenatal Iron Supplements: Safety and Efficacy in Tanzania" (NCT01119612; http://clinicaltrials.gov/show/NCT01119612 ).

Influence of gestational weight gain on baby's birth weight in Addis Ababa, Central Ethiopia: a follow-up study

BACKGROUND

Gestational weight gain (GWG) is an important indicator of fetal well-being during pregnancy. Inadequate or excessive GWG could have undesirable effects on birth weight. However, information regarding the influence of GWG on birth weight is lacking from the Ethiopian setting.

OBJECTIVE

This study aimed to determine the influence of GWG and other maternal-related factors on birth weight in Addis Ababa, Ethiopia.

DESIGN AND METHODS

A cohort of pregnant women who received the first antenatal care before or at 16 weeks of gestation in health centres in Addis Ababa were followed from 10 January 2019 to 25 September 2019. Data were collected using a structured questionnaire and medical record reviews. We conducted a multivariable linear regression analysis to determine the independent effect of gestational weight on birth weight.

RESULTS

Of the 395 women enrolled in the study, the participants' pregnancy outcome was available for 329 (83.3%). The mean birth weight was 3130 (SD, 509) g. The proportion of low birth weight (<2500 g) was 7.5% (95% CI 4.8% to 11.0%). Babies born to underweight women were 150.9 g (95% CI 5.8 to 308.6 g, p=0.049) lighter than babies born to normal-weight women. Similarly, babies whose mothers gained inadequate weight were 248 g (95% CI 112.8 to 383.6 g, p<0.001) lighter than those who gained adequate weight. Moreover, babies whose mothers had a previous history of abortion or miscarriages or developed gestational hypertension in the current pregnancy were 147.2 g (95% CI 3.2 to 291.3 g, p=0.045) and 310.7 g (95% CI 62.7 to 552.8 g, p=0.012) lighter, respectively, compared with those whose mothers had not.

CONCLUSIONS

Prepregnancy weight, GWG, having had a previous history of abortion or miscarriages, and developing gestational hypertension during a current pregnancy were independently associated with birth weight. Pregnancy-related weight management should be actively promoted through intensive counseling during routine antenatal care contacts.

Associations Between Gestational Weight Gain and Adverse Birth Outcomes: A Population-Based Retrospective Cohort Study of 9 Million Mother-Infant Pairs

Background

Gestational weight gain (GWG) reflects maternal nutrition during pregnancy. However, the associations between maternal GWG and adverse birth outcomes are inconclusive.

Objective

We aimed to examine the associations between maternal GWG and adverse birth outcomes according to maternal pre-pregnancy body mass index (BMI) categories in a large, multiethnic and diverse population in the U.S.

Study Design

We used nationwide birth certificate data from the National Vital Statistics System to examine the association of GWG (below, within and above the Institute of Medicine [IOM] guidelines) with six adverse birth outcomes (preterm birth, low birthweight, macrosomia, small for gestational age [SGA], large for gestational age [LGA], and low Apgar score) according to the pre-pregnancy BMI categories (underweight to obesity grade 3). Multivariable logistic regression analyses were performed to estimate the odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of 9,191,842 women aged 18–49 years at delivery with live singleton births were included. Among them, 24.5% of women had GWG below IOM guidelines, 27.6% within the guidelines, and 47.9% above the guidelines. Compared with maternal GWG within guidelines, GWG below guidelines was associated with higher odds of preterm birth (OR = 1.52, 95%CI = 1.51–1.53), low birthweight (OR = 1.46, 95%CI = 1.45–1.47) and SGA (OR = 1.44, 95%CI = 1.43–1.45). In contrast, maternal GWG above guidelines was associated with higher odds of macrosomia (OR = 2.12, 95%CI = 2.11–2.14) and LGA (OR = 2.12, 95%CI = 2.11–2.14). In addition, maternal GWG below or above guidelines had slightly higher odds of low Apgar score (below guidelines: OR = 1.04, 95%CI = 1.03–1.06, above guidelines: OR = 1.17, 95%CI = 1.15–1.18). The results were largely similar among women with GWG below or above guidelines across pre-pregnancy BMI categories of underweight, overweight, and obesity grade 1 to grade 3.

Conclusion

Pregnant women with GWG below or above the IOM guidelines have increased odds of selected adverse infant birth outcomes. Monitoring maternal GWG could enable physicians to provide tailored nutrition and exercise advice as well as prenatal care to pregnant women to reduce the likelihood of adverse birth outcomes.

When husband migrate: effects of international migration of husbands on fetal outcomes, body mass index and gestational weight of female spouses that stay behind

BACKGROUND

International labour migration continues to be an integral component in Sri Lanka's economic development. Previous research indicates an adverse perinatal outcome in association with low maternal pre-pregnancy body mass index (PBMI) and gestational weight gain (GWG). However, evidence of this association is limited in migrant families. This study aims to investigate the associations between PBMI, GWG among lactating mothers (LM), and fetal outcomes in migrant households, where the father is the migrant worker.

METHODS

A secondary data analysis was done using a nationally representative sample of 7,199 LM. There were 284 LM whose husbands were international migrant workers. Maternal factors were taken as PBMI<18.5 kg/m² and GWG<7kg. Preterm birth and low birth weight (LBW) were taken as fetal outcomes. Binary logistic regression was performed to assess the associated factors.

RESULTS

There was significant difference between LM from migrant and non-migrant households with regards to place of residency, ethnicity, household monthly income, household food security, average household members, husband's education and husband's age. Among migrant, PBMI<18.5 kg/m² was associated with current BMI and mode of delivery. Migrant LM had significantly higher weight gain (≥12 kg) during pregnancy (p=0.005), were multiparous (p=0.008), delivered in private hospital (p=0.000), lesser percentage of underweight (p=0.002) and higher birthweight (p=0.03) than non-migrant LM. Logistic regression model revealed that for each kilogram increment in birthweight and GWG, preterm delivery decreased by 89%(OR=0.11;95%CI:0.04-0.28) and LBW decreased by 12%(OR=0.89;95%CI:0.81-0.97) respectively. Caesarean deliveries were positively associated with low GWG.

CONCLUSION

Our study showed LM in migrant families had invested remittances to utilize private health facilities for deliveries, to improve weight gain during pregnancy and adequate PBMI to deliver higher birth weight babies. In depth study is needed to understand further utilisation of remittances to improve fetal outcomes by increasing birthweight and GWG in migrant families.

Investigating the normalization and normative views of gestational weight gain: Balancing recommendations with the promotion and support of healthy pregnancy diets

OBJECTIVES

Gestational weight gain (GWG) is increasingly monitored in the United States and Canada. While promoting healthy GWG offers benefits, there may be costs with over-surveillance. We aimed to explore these costs/benefits.

METHODS

Quantitative data from 350 pregnant survey respondents and qualitative focus group data from 43 pregnant/post-partum and care-provider participants were collected in the Mothers to Babies (M2B) study in Hamilton, Canada. We report descriptive statistics and discussion themes on GWG trajectories, advice, knowledge, perceptions, and pregnancy diet. Relationships between GWG monitoring/normalization and worry, knowledge, diet quality, and sociodemographics-namely low-income and racialization-were assessed using χ² tests and a linear regression model and contextualized with focus group data.

RESULTS

Most survey respondents reported GWG outside recommended ranges but rejected the mid-20th century cultural norm of "eating for two"; many worried about gaining excessively. Conversely, respondents living in very low-income households were more likely to be gaining less than recommended GWG and to worry about gaining too little. A majority had received advice about GWG, yet half were unable to identify the range recommended for their prepregnancy BMI. This proportion was even lower for racialized respondents. Pregnancy diet quality was associated with household income, but not with receipt or understanding of GWG guidance. Care-providers encouraged normalized GWG, while worrying about the consequences of pathologizing "abnormal" GWG.

CONCLUSIONS

Translation of GWG recommendations should be done with a critical understanding of GWG biological normalcy. Supportive GWG monitoring and counseling should consider clinical, socioeconomic, and community contexts.

Association Between Household and Maternal Socioeconomic Factors with Birth Outcomes in the Democratic Republic of Congo and South Africa: A Comparative Study

OBJECTIVE

To assess and compare the associations between household socioeconomic (SES) factors with birth outcomes (low birth weight (LBW), small-for-gestational age (SGA) and preterm birth (PTB)) in the Democratic Republic of Congo (DRC) and South Africa (SA).

METHODS

Cross-sectional data of mother-newborn pairs collected in 2017 in the DRC were compared with mother-newborn pairs data from the SA Soweto first 1000-days pregnancy cohort study (2013-2016). Country-specific and pooled multivariable logistic regressions analyses assessed the associations between maternal education, marital status, and housing with LBW, SGA, and PTB adjusted for maternal anthropometry and obstetric factors.

RESULTS

1084 mother-newborn pairs were recruited (DRC: 256; SA: 828). The rates of LBW, PTB and SGA were, 11.5%, 17.1% and 32.8% in the DRC and 15.9%, 10.5% and 20.1% in SA. SES factors differed between countries and sex. In the DRC, being married decreased the odds of having LBW and PTB children by 86% and 80%, respectively. In SA, being a mother with secondary level of education and above was associated with 86% reduced odds of SGA. In the pooled analyses, women with secondary level of education and above had a 2.2-fold increase in odds of giving birth to a PTB newborn. Country of residence and maternal nutritional status were stronger predictors of birth outcomes than SES factors.

CONCLUSION FOR PRACTICE

In sub-Saharan Africa, policies aiming to alleviate women's education combined with improved social support and household SES prior to and during pregnancy are critical to optimal neonatal outcomes and strategic to achieve the Sustainable Development Goals.

Does weight gain during pregnancy influence antenatal depressive symptoms? A systematic review and meta-analysis

OBJECTIVE

Conflicting results have been reported on the associations between inappropriate gestational weight gain (GWG) and the risk of depression during pregnancy. This systematic review and meta-analysis aimed to investigate the association between weight gain during pregnancy and the risk of antenatal depressive symptoms.

METHODS

A systematic search was performed in PubMed, EMBASE, Scopus, PsycINFO and CINAHL databases from database inception to July 31, 2020, and relevant studies were identified. Observational studies assessing the association between GWG using the Institute of Medicine (IOM) recommendations and maternal depressive symptoms during pregnancy were included. We used a random-effects model to estimate risks. Subgroup and sensitivity analyses were performed.

RESULTS

Of the 1232 studies identified, 19 met the inclusion criteria. The pooled odds ratio for the association between inadequate, excessive and total GWG and antenatal depressive symptoms was 1.09 (95% CI; 0.94-1.25), 0.94 (95% CI; 0.85-1.03), and 0.99 (95% CI, 0.88, 01.13), respectively. Sensitivity and subgroup analyses provided consistent findings.

CONCLUSION

The findings showed that neither women who gained weight below IOM recommendations, nor women who gained weight above IOM recommendations were more likely to experience depressive symptoms during pregnancy compared with women whose weight gain was within the recommended range. Studies focus on trimester-specific GWG and antenatal depressive symptoms are needed.

Gestational weight gain and its effect on birth outcomes in sub-Saharan Africa: Systematic review and meta-analysis

INTRODUCTION

An increased metabolic demand during pregnancy is fulfilled by gaining sufficient gestational weight. Women who gain inadequate-weight are at a high-risk of premature birth or having a baby with low-birth weight. However, women who gain excessive-weight are at a high-risk of having a baby with macrosomia. The aim of this review was to determine the distribution of gestational weight gain and its association with birth-outcomes in Sub-Saharan Africa.

METHODS

For this systematic review and meta-analysis, we performed a literature search using PubMed, Medline, Embase, Scopus, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases. We searched grey-literature from Google and Google Scholar, and region-specific journals from the African Journals Online (AJOL) database. We critically appraised the included studies using the Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies. Two independent reviewers evaluated the quality of the studies and extracted the data. We calculated pooled relative-risks (RR) with 95% confidence intervals.

RESULTS

Of 1450 retrieved studies, 26 met the inclusion criteria. Sixteen studies classified gestational weight gain according to the United States Institute of Medicine recommendations. The percentage adequate amount of gestational weight ranged from 3% to 62%. The percentage of inadequate weight was >50% among nine studies. Among underweight women, the percentage of women who gained inadequate gestational weight ranged from 67% to 98%. Only two studies were included in the meta-analyses to evaluate the association of gestational weight gain with pre-eclampsia and macrosomia. No difference was observed among women who gained inadequate and adequate gestational weight regarding experiencing pre-eclampsia (RR, 0.71; 95% CI: 0.22, 2.28, P = 0.57). Excessive gestational weight gain was not significantly associated with macrosomia compared to adequate weight gain (RR, 0.68; 95% CI: 0.38, 1.22, P = 0.20).

CONCLUSION

A substantial proportion of sub-Saharan African women gain inadequate gestational weight particularly high among underweight women. Future interventions would need to design effective pre-pregnancy weight management strategies.

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.

Maternal Prepregnancy Body Mass Index, Gestational Weight Gain, and Risk of Adverse Perinatal Outcomes in Taiwan: A Population-Based Birth Cohort Study

Epidemiological studies have shown that maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) are associated with increased risk of perinatal outcomes. However, the evidence of such associations in Asian populations is limited. We conducted a secondary data analysis to investigate the relationships of prepregnancy BMI and GWG with the risks of adverse perinatal outcomes, including gestational diabetes (GDM), gestational hypertension (GHTN), preeclampsia, cesarean delivery, preterm birth, low birth weight (LBW), and macrosomia. We categorized prepregnancy BMI by the WHO classification and GWG by the Institute of Medicine guidelines. We performed adjusted logistic regression models to estimate the odds ratios of adverse perinatal outcomes. A total of 19,052 women were included; prepregnancy overweight and obesity were associated with a greater risk of GDM, GHTN, preeclampsia, cesarean delivery, preterm birth, and macrosomia. Women with excessive GWG had a greater risk of GHTN, preeclampsia, cesarean delivery, and macrosomia. In conclusion, regardless of the range of GWG during pregnancy, maternal prepregnancy BMI is significantly associated with the risk of adverse perinatal outcomes in Taiwan. Public health attention regarding obesity reduction before conception and prenatal counseling for optimal GWG is needed to mitigate the risk of poor perinatal outcomes.

Gestational weight gain outside the Institute of Medicine recommendations and adverse pregnancy outcomes: analysis using individual participant data from randomised trials

BACKGROUND

High Body Mass Index (BMI) and gestational weight gain (GWG) affect an increasing number of pregnancies. The Institute of Medicine (IOM) has issued recommendations on the optimal GWG for women according to their pre-pregnancy BMI (healthy, overweight or obese). It has been shown that pregnant women rarely met the recommendations; however, it is unclear by how much. Previous studies also adjusted the analyses for various women's characteristics making their comparison challenging.

METHODS

We analysed individual participant data (IPD) of healthy women with a singleton pregnancy and a BMI of 18.5 kg/m2 or more from the control arms of 36 randomised trials (16 countries). Adjusted odds ratios (aOR) and 95% confidence intervals (CI) were used to describe the association between GWG outside (above or below) the IOM recommendations (2009) and risks of caesarean section, preterm birth, and large or small for gestational age (LGA or SGA) infants. The association was examined overall, within the BMI categories and by quartile of GWG departure from the IOM recommendations. We obtained aOR using mixed-effects logistic regression, accounting for the within-study clustering and a priori identified characteristics.

RESULTS

Out of 4429 women (from 33 trials) meeting the inclusion criteria, two thirds gained weight outside the IOM recommendations (1646 above; 1291 below). The median GWG outside the IOM recommendations was 3.1 kg above and 2.7 kg below. In comparison to GWG within the IOM recommendations, GWG above was associated with increased odds of caesarean section (aOR 1.50; 95%CI 1.25, 1.80), LGA (2.00; 1.58, 2.54), and reduced odds of SGA (0.66; 0.50, 0.87); no significant effect on preterm birth was detected. The relationship between GWG below the IOM recommendation and caesarean section or LGA was inconclusive; however, the odds of preterm birth (1.94; 1.31, 2.28) and SGA (1.52; 1.18, 1.96) were increased.

CONCLUSIONS

Consistently with previous findings, adherence to the IOM recommendations seem to help achieve better pregnancy outcomes. Nevertheless, even in the context of clinical trials, women find it difficult to adhere to them. Further research should focus on identifying ways of achieving a healthier GWG as defined by the IOM recommendations.

Rate of gestational weight gain and adverse pregnancy outcomes in rural nulliparous women: a prospective cohort analysis from China

Both inadequate and excessive gestational weight gain (GWG) have been shown to increase the risk of adverse pregnancy outcomes, but the risk profiles of GWG rate are unclear. We aimed to examine the associations between GWG rate in the second/third trimester and a spectrum of pregnancy outcomes. This study consisted of 14 219 Chinese rural nulliparous women who participated in a randomised controlled trial of prenatal micronutrient supplementation during 2006–2009. The outcomes included stillbirth, neonatal and infant death, preterm birth, macrosomia, low birth weight (LBW) and large and small for gestational age (LGA and SGA, respectively). GWG rate was divided into quintiles within each BMI category. Compared with women in the middle quintile, those in the lowest quintile had higher risks of neonatal death (adjusted OR 2·27; 95 % CI 1·03, 5·02), infant death (adjusted OR 1·85; 95 % CI 1·02, 3·37) and early preterm birth (adjusted OR 2·33; 95 % CI 1·13, 4·77), while those in the highest quintile had higher risks of overall preterm birth (adjusted OR 1·28; 95 % CI 1·04, 1·59), late preterm birth (adjusted OR 1·25; 95 % CI 1·00, 1·56), LBW (adjusted OR 1·48; 95 % CI 1·02, 2·15), macrosomia (adjusted OR 1·89; 95 % CI 1·46, 2·45) and LGA (adjusted OR 1·56; 95 % CI 1·31, 1·85). In conclusion, very low and very high GWG rates in the second/third trimester appear to be associated with adverse pregnancy outcomes in Chinese nulliparous women, indicating that an appropriate GWG rate during pregnancy is necessary for neonatal health.

Ethnicity and Immigration Status as Risk Factors for Gestational Diabetes Mellitus, Anemia and Pregnancy Outcomes Among Food Insecure Women Attending the Montreal Diet Dispensary Program

OBJECTIVE

The primary aim of this study was to characterize the rate of adverse pregnancy outcomes in a multicultural group of low-income women.

METHODS

Data were extracted from the Montreal Diet Dispensary's database between June 2013 and December 2015. Risk was evaluated using logistic regression adjusted for covariates.

RESULTS

Of the 1,387 pregnancies, the prevalence of gestational diabetes mellitus (GDM) was 17.2% (95% confidence interval [CI], 15.1% to 19.3%), maternal anemia 44.9% (95% CI, 41.9% to 47.9%) and hypertension 3.8% (95% CI, 2.8% to 4.8%). The prevalence of small-for-gestational-age infants was 5.5% (95% CI, 4.3% to 6.7%), preterm births 4.7% (95% CI, 3.6% to 5.9%), low birthweight 4.2% (95% CI, 3.1% to 5.2%) and large-for-gestational-age infants was 10.6% (95% CI, 9.0% to 12.2%). Asian women had an increased odds of gestational diabetes mellitus (adjusted odds ratio [aOR], 1.86; 95% CI, 1.17 to 2.98) and SGA infants (aOR, 2.35; 95% CI 1.21 to 4.57) compared with white women. Anemia was more likely for black women compared with white women (aOR, 1.74; 95% CI, 1.29 to 2.35). Black women were more at risk of preterm birth (aOR, 1.79; 95% CI, 1.01 to 3.19). Immigrants showed an increased risk of maternal anemia compared with Canadian-born women (aOR, 1.85; 95% CI, 1.06 to 3.21).

CONCLUSIONS

As disparities in maternal and infant outcomes were present, nutritional intervention(s) need to be targeted toward prevention of adverse pregnancy outcomes, prioritization of higher-risk groups and adaptation of the program to a multiethnic low-income population.

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.

Maternal intake of milk and milk proteins is positively associated with birth weight: A prospective observational cohort study

BACKGROUND

A striking number of low birth weight (LBW) Indian babies are born annually. Previous studies have confirmed the positive association between milk intake and birth weight. However, the relations between protein and vitamin B₁₂ from milk and birth weight have not been systematically explored.

AIMS

We examined the relations between birth weight and maternal intake of milk, protein from milk and vitamin B₁₂ from milk.

METHODS

This prospective, observational cohort study was conducted in an urban South Indian hospital. The dietary intakes of milk and milk products were assessed using validated food frequency questionnaire and at delivery birth outcomes were measured. The relations between milk products, milk protein, and vitamin B₁₂ from milk with birth weight and gestational weight gain were assessed in 2036 births with first trimester dietary and delivery data.

RESULTS

Median consumption of milk products in the first trimester was 310 g·day^-1 and average birth weight was 2876 g. Birth weight was positively associated with intake of milk products and of % protein from milk products (%milk protein) in the first trimester [β = 86.8, 95% confidence interval (CI): 29.1, 144.6; β = 63.1, 95% CI: 10.8, 115.5; P < 0.001 for both]. Intake of milk products and of %milk protein in the third trimester was positively associated with gestational weight gain (GWG) between the second and third trimester (One-way ANOVA, P < 0.001 and = 0.001, respectively). Neither birth weight nor GWG were associated with %vitamin B₁₂ from milk products.

CONCLUSIONS

These findings indicate that intake of milk products in the first trimester and especially, protein from milk products is positively associated with birth weight in this South Asian Indian population.

Obesity and gynaecological and obstetric conditions: umbrella review of the literature

Objective To study the strength and validity of associations between adiposity and risk of any type of obstetric or gynaecological conditions.Design An umbrella review of meta-analyses.Data sources PubMed, Cochrane database of systematic reviews, manual screening of references for systematic reviews or meta-analyses of observational and interventional studies evaluating the association between adiposity and risk of any obstetrical or gynaecological outcome.Main outcomes Meta-analyses of cohort studies on associations between indices of adiposity and obstetric and gynaecological outcomes.Data synthesis Evidence from observational studies was graded into strong, highly suggestive, suggestive, or weak based on the significance of the random effects summary estimate and the largest study in the included meta-analysis, the number of cases, heterogeneity between studies, 95% prediction intervals, small study effects, excess significance bias, and sensitivity analysis with credibility ceilings. Interventional meta-analyses were assessed separately.Results 156 meta-analyses of observational studies were included, investigating associations between adiposity and risk of 84 obstetric or gynaecological outcomes. Of the 144 meta-analyses that included cohort studies, only 11 (8%) had strong evidence for eight outcomes: adiposity was associated with a higher risk of endometrial cancer, ovarian cancer, antenatal depression, total and emergency caesarean section, pre-eclampsia, fetal macrosomia, and low Apgar score. The summary effect estimates ranged from 1.21 (95% confidence interval 1.13 to 1.29) for an association between a 0.1 unit increase in waist to hip ratio and risk endometrial cancer up to 4.14 (3.61 to 4.75) for risk of pre-eclampsia for BMI >35 compared with <25. Only three out of these eight outcomes were also assessed in meta-analyses of trials evaluating weight loss interventions. These interventions significantly reduced the risk of caesarean section and pre-eclampsia, whereas there was no evidence of association with fetal macrosomia.Conclusions Although the associations between adiposity and obstetric and gynaecological outcomes have been extensively studied, only a minority were considered strong and without hints of bias.

Examining the provisional guidelines for weight gain in twin pregnancies: a retrospective cohort study

BACKGROUND

Weight gain during pregnancy has an important impact on maternal and neonatal health. Unlike the Institute of Medicine (IOM) recommendations for weight gain in singleton pregnancies, those for twin gestations are termed "provisional", as they are based on limited data. The objectives of this study were to determine the neonatal and maternal outcomes associated with gaining weight below, within and above the IOM provisional guidelines on gestational weight gain in twin pregnancies, and additionally, to explore ranges of gestational weight gain among women who delivered twins at the recommended gestational age and birth weight, and those who did not.

METHODS

A retrospective cohort study of women who gave birth to twins at ≥20 weeks gestation, with a birth weight ≥ 500 g was conducted in Nova Scotia, Canada (2003-2014). Our primary outcome of interest was small for gestational age (<10th percentile). In order to account for gestational age at delivery, weekly rates of 2nd and 3rd trimester weight gain were used to categorize women as gaining below, within, or above guidelines. We performed traditional regression analyses for maternal outcomes, and to account for the correlated nature of the neonatal outcomes in twins, we used generalized estimating equations (GEE).

RESULTS

A total of 1482 twins and 741 mothers were included, of whom 27%, 43%, and 30% gained below, within, and above guidelines, respectively. The incidence of small for gestational age in these three groups was 30%, 21%, and 20%, respectively, and relative to gaining within guidelines, the adjusted odds ratios were 1.44 (95% CI 1.01-2.06) for gaining below and 0.92 (95% CI 0.62-1.36) for gaining above. The gestational weight gain in women who delivered twins at 37-42 weeks with average birth weight ≥ 2500 g and those who delivered twins outside of the recommend ranges were comparable to each other and the IOM recommendations.

CONCLUSIONS

While gestational weight gain below guidelines for twins was associated with some adverse neonatal outcomes, additional research exploring alternate ranges of gestational weight gain in twin pregnancies is warranted, in order to optimize neonatal and maternal outcomes.

Impact of Gestational Weight Gain on Cesarean Delivery Risk, Perinatal Birth Weight and Gestational Age in Women with Normal Pre-pregnancy BMI

Background

Gestational weight gain (GWG) proportional to body mass index before pregnancy is one of the factors on maternal and neonatal outcomes. The aim of the current study was to assess association between GWG, and cesarean section, birth weight and gestational age at birth in women with normal BMI prior to pregnancy.

Methods

This was a cross-sectional study carried out in 103 hospitals in Tehran, the capital of Iran, from July 6 to 21, 2015. The data were extracted by 103 trained midwives. Finally, 2394 pregnant women with normal BMI before pregnancy and singleton birth were examined. GWG was categorized based on Institute of Medicine (IOM) recommendations.

Results

Prevalence of low birth weight (LBW) was 5.41% and prevalence of macrosomia was 2.18%. The prevalence of LBW in women with GWG less than the weight gain recommended by IOM was 2.13 times [95% confidence interval (CI) 1.13-4.02, P = 0.019] more than in women with GWG equal to the weight gain recommended by IOM. There was no statistically significant difference in the prevalence of LBW between women with GWG more than recommended weight gain by IOM and women with GWG equal to the weight gain recommended by IOM (OR = 1.21, 95% CI 0.61-2.38, P = 0.580).

Conclusion

After controlling for confounding variables, the prevalence of cesarean section and preterm birth had no significant difference at various levels of GWG. Accordingly, the prevalence of LBW among women with GWG less than the recommended weight gain by IOM was significantly 2.13 more than that among women with GWG equal to the recommended weight gain by IOM.

Association of Gestational Weight Gain With Maternal and Infant Outcomes: A Systematic Review and Meta-analysis

IMPORTANCE

Body mass index (BMI) and gestational weight gain are increasing globally. In 2009, the Institute of Medicine (IOM) provided specific recommendations regarding the ideal gestational weight gain. However, the association between gestational weight gain consistent with theIOM guidelines and pregnancy outcomes is unclear.

OBJECTIVE

To perform a systematic review, meta-analysis, and metaregression to evaluate associations between gestational weight gain above or below the IOM guidelines (gain of 12.5-18 kg for underweight women [BMI <18.5]; 11.5-16 kg for normal-weight women [BMI 18.5-24.9]; 7-11 kg for overweight women [BMI 25-29.9]; and 5-9 kg for obese women [BMI ≥30]) and maternal and infant outcomes.

DATA SOURCES AND STUDY SELECTION

Search of EMBASE, Evidence-Based Medicine Reviews, MEDLINE, and MEDLINE In-Process between January 1, 1999, and February 7, 2017, for observational studies stratified by prepregnancy BMI category and total gestational weight gain.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by 2 independent reviewers. Odds ratios (ORs) and absolute risk differences (ARDs) per live birth were calculated using a random-effects model based on a subset of studies with available data.

MAIN OUTCOMES AND MEASURES

Primary outcomes were small for gestational age (SGA), preterm birth, and large for gestational age (LGA). Secondary outcomes were macrosomia, cesarean delivery, and gestational diabetes mellitus.

RESULTS

Of 5354 identified studies, 23 (n = 1 309 136 women) met inclusion criteria. Gestational weight gain was below or above guidelines in 23% and 47% of pregnancies, respectively. Gestational weight gain below the recommendations was associated with higher risk of SGA (OR, 1.53 [95% CI, 1.44-1.64]; ARD, 5% [95% CI, 4%-6%]) and preterm birth (OR, 1.70 [1.32-2.20]; ARD, 5% [3%-8%]) and lower risk of LGA (OR, 0.59 [0.55-0.64]; ARD, -2% [-10% to -6%]) and macrosomia (OR, 0.60 [0.52-0.68]; ARD, -2% [-3% to -1%]); cesarean delivery showed no significant difference (OR, 0.98 [0.96-1.02]; ARD, 0% [-2% to 1%]). Gestational weight gain above the recommendations was associated with lower risk of SGA (OR, 0.66 [0.63-0.69]; ARD, -3%; [-4% to -2%]) and preterm birth (OR, 0.77 [0.69-0.86]; ARD, -2% [-2% to -1%]) and higher risk of LGA (OR, 1.85 [1.76-1.95]; ARD, 4% [2%-5%]), macrosomia (OR, 1.95 [1.79-2.11]; ARD, 6% [4%-9%]), and cesarean delivery (OR, 1.30 [1.25-1.35]; ARD, 4% [3%-6%]). Gestational diabetes mellitus could not be evaluated because of the nature of available data.

CONCLUSIONS AND RELEVANCE

In this systematic review and meta-analysis of more than 1 million pregnant women, 47% had gestational weight gain greater than IOM recommendations and 23% had gestational weight gain less than IOM recommendations. Gestational weight gain greater than or less than guideline recommendations, compared with weight gain within recommended levels, was associated with higher risk of adverse maternal and infant outcomes.

It's About Time: A Survival Approach to Gestational Weight Gain and Preterm Delivery

There is substantial interest in understanding the impact of gestational weight gain on preterm delivery (delivery <37 weeks). The major difficulty in analyzing the association between gestational weight gain and preterm delivery lies in their mutual dependence on gestational age, as weight naturally increases with increasing pregnancy duration. In this study, we untangle this inherent association by reframing preterm delivery as time to delivery and assessing the relationship through a survival framework, which is particularly amenable to dealing with time-dependent covariates, such as gestational weight gain. We derive the appropriate analytical model for assessing the relationship between weight gain and time to delivery when weight measurements at multiple time points are available. Since epidemiologic data may be limited to weight gain measurements taken at only a few time points or at delivery only, we conduct simulation studies to illustrate how several strategically timed measurements can yield unbiased risk estimates. Analysis of the study of successive small-for-gestational-age births demonstrates that a naive analysis that does not account for the confounding effect of time on gestational weight gain suggests a strong association between higher weight gain and later delivery (hazard ratio: 0.89, 95% confidence interval = 0.84, 0.93). Properly accounting for the confounding effect of time using a survival model, however, mitigates this bias (hazard ratio: 0.98, 95% confidence interval = 0.97, 1.00). These results emphasize the importance of considering the effect of gestational age on time-varying covariates during pregnancy, and the proposed methods offer a convenient mechanism to appropriately analyze such data.See Video Abstract at http://links.lww.com/EDE/B13.

Are women who quit smoking at high risk of excess weight gain throughout pregnancy?

Background

Smoking cessation has been reported to be associated with high total gestational weight gain (GWG), which itself is a risk factor for adverse maternal-infant outcomes. Recent studies have criticized conventional single measures of GWG, since they may lead to biased results. Therefore, we aimed to compare patterns of GWG based on serial antenatal weight measurements between women who: never smoked, quit during pregnancy, continued to smoke.

Methods

Participants (N = 509) of our longitudinal study were recruited from seven antenatal clinics in Southwestern Ontario. Serial GWG measurements were abstracted from medical charts, while information on smoking status was obtained from a self-administered questionnaire at a median gestational age of 32 (27–37) weeks. GWG patterns were assessed by fitting piecewise mixed-effects models. First trimester weight gains and weekly rates for the last two trimesters were compared by smoking status.

Results

During the first trimester, women who never smoked and those who quit during pregnancy gained on average 1.7 kg (95 % CI: 1.4–2.1) and 1.2 kg (0.3–2.1), respectively, whereas women who continued smoking gained more than twice as much (3.5 kg, 2.4–4.6). Weekly rate of gain in the second and third trimesters was highest in women who quit smoking (0.60 kg/week, 0.54–0.65), approximately 20 and 50 % higher than in women who never smoked and those who smoked during pregnancy, respectively.

Conclusions

In this longitudinal study to examine GWG by smoking status based on serial GWG measurements, we found that women who quit smoking experienced a rapid rate of gain during the last two trimesters, suggesting that this high-risk group may benefit from targeted interventions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12884-016-1056-z) contains supplementary material, which is available to authorized users.

Rate of gestational weight gain and preterm birth in relation to prepregnancy body mass indices and trimester: a follow-up study in China

Background

To evaluate the association between rate of gestational weight gain and preterm birth varying prepregnancy body mass indices and trimester.

Methods

Data from Maternal and Newborn’s Health Monitoring System on 17475 pregnant women who delivered live singletons at ≥ 28 weeks of gestation between October 2013 and September 2014 from 12 districts/counties of 6 provinces in China and started prenatal care at ≤ 12 weeks of gestation was analyzed. Gestational weight gain was categorized by rate of weight gain during the 2^nd and 3^rd trimester, based on the 2009 Institute of Medicine guidelines. Multivariable binary logistic regression models were conducted to investigate the association between rate of gestational weight gain and preterm birth stratified by prepregnancy body mass indices and trimester.

Results

Excessive weight gain occurred in 57.9 % pregnant women, and insufficient weight gain 12.5 %. Average rate of gestational weight gain in 2^nd and 3^rd trimester was independently associated with preterm birth (U-shaped), and the association varied by prepregnancy body mass indices and trimesters. In underweight women, excessive gestational weight gain was positively associated with preterm birth (OR 1.93, 95 % confidence interval (CI): 1.29- 2.88) when compared with women who gained adequately. While in overweight/obese women, insufficient gestational weight gain was positively associated with preterm birth (OR 3.92, 95 % CI: 1.13–13.67). When stratifying by trimester, we found that excessive weight gain in 3^rd trimester had a significantly positive effect on preterm birth (OR 1.27, 95 % CI: 1.02–1.58).

Conclusions

Excessive gestational weight gain among underweight pregnant women, insufficient gestational weight gain among overweight/obese women and excessive gestational weight gain in 3^rd trimester were important predictors of preterm birth.

Rate of Second and Third Trimester Weight Gain and Preterm Delivery Among Underweight and Normal Weight Women

Objectives Low gestational weight gain (GWG) in the second and third trimesters has been associated with increased risk of preterm delivery (PTD) among women with a body mass index (BMI) < 25 mg/m(2). However, few studies have examined whether this association differs by the assumptions made for first trimester gain or by the reason for PTD. Methods We examined singleton pregnancies during 2000-2008 among women with a BMI < 25 kg/m(2) who delivered a live-birth ≥28 weeks gestation (n = 12,526). Women received care within one integrated health care delivery system and began prenatal care ≤13 weeks. Using antenatal weights measured during clinic visits, we interpolated GWG at 13 weeks gestation then estimated rate of GWG (GWGrate) during the second and third trimesters of pregnancy. We also estimated GWGrate using the common assumption of a 2-kg gain for all women by 13 weeks. We examined the covariate-adjusted association between quartiles of GWGrate and PTD (28-36 weeks gestation) using logistic regression. We also examined associations by reason for PTD [premature rupture of membranes (PROM), spontaneous labor, or medically indicated]. Results Mean GWGrate did not differ among term and preterm pregnancies regardless of interpolated or assumed GWG at 13 weeks. However, only with GWGrate estimated from interpolated GWG at 13 weeks, we observed a U-shaped relationship where odds of PTD increased with GWGrate in the lowest (OR 1.36, 95 % CI 1.10, 1.69) or highest quartile (OR 1.49, 95 % CI 1.20, 1.85) compared to GWGrate within the second quartile. Further stratifying by reason, GWGrate in the lowest quartile was positively associated with spontaneous PTD while GWGrate in the highest quartile was positively associated with PROM and medically indicated PTD. Conclusions Accurate estimates of first trimester GWG are needed. Common assumptions applied to all pregnancies may obscure the association between GWGrate and PTD. Further research is needed to fully understand whether these associations are causal or related to common antecedents.

Gestational weight gain and preterm birth in obese women: a systematic review and meta-analysis

BACKGROUND

Prepregnant obesity is a global concern and gestational weight gain has been found to influence the risks of preterm birth.

OBJECTIVE

To assess the relationship between gestational weight gain and risk for preterm birth in obese women.

SEARCH STRATEGY

Four electronic databases were searched from 18 February through to 28 April 2015.

SELECTION CRITERIA

Primary research reporting preterm birth as an outcome in obese women and gestational weight gain as a variable that could be compared to the 2009 Institute of Medicine's recommendations.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trials for inclusion. The Newcastle Ottawa Scale was used to assess study bias.

MAIN RESULTS

Our search identified six studies meeting the inclusion criteria; five were conducted in the USA and one in Peru. Four studies with a total of 10 171 obese women were meta-analysed. Significant heterogeneity was found between studies in the pooled analysis. Results for indicated preterm birth in obese women with gestational weight gain above the Institute of Medicine's recommendations showed increased risk (adjusted odds ratio 1.54; 95% CI 1.09-2.16).

CONCLUSIONS

Available science on this topic is limited to special populations of obese pregnant women. Generalisable research is needed to assess the variation in risk for preterm birth in obese women by differences in gestational weight gain and class of obesity controlling for significant variables in the pathway to preterm birth. This research has the potential to illuminate new science impacting preterm birth and interventions for prevention.

The effect of gestational weight gain on likelihood of referral to obstetric care for women eligible for primary, midwife-led care after antenatal booking

OBJECTIVE

to examine the effect of gestational weight gain (GWG) on likelihood of referral from midwife-led to obstetrician-led care during pregnancy and childbirth for women in primary care at the outset of their pregnancy.

DESIGN

secondary analysis of data from a prospective cohort study.

SETTING

Dutch midwife-led practices.

PARTICIPANTS

a cohort of 1288 women of Northern European descent, with uncomplicated, singleton pregnancy at antenatal booking who consequently were eligible for primary, midwife-led care.

MEASUREMENTS

because of the absence of an established GWG guideline in the Netherlands, we compared the effect of inadequate and excessive GWG according to two GWG guidelines: the criterion traditionally used, which is based on knowledge of the physiological components of GWG, advising 10-15kg as a normal GWG irrespective of a woman׳s BMI category, and the 2009 Institute of Medicine recommendations (IOMr) on GWG, which provide BMI related advice. Outcome measures were: number of women referred from midwife-led to obstetrician-led care during pregnancy and during childbirth; indications of referral and birth outcomes.

FINDINGS

GWG above traditional criteria (Tc; >15kg between 12 and 36 weeks) was associated with increased odds for referral during childbirth (adjusted odds ratio (aOR) 1.88; 95% confidence interval (CI) 1.22-2.90), but had no effect on referral during pregnancy (aOR .86; 95% CI .57-1.30). No associations were established between GWG below Tc (<10kg) and referral during pregnancy (aOR 1.08; 95% CI .78-1.50) or childbirth (aOR 1.08; 95% CI .74-1.56). No associations were found between GWG below and above the IOMr and referral during pregnancy (below IOMr: aOR 1.01; 95% CI .71-1.45; above IOMr: aOR .89; 95% CI .61-1.28) or childbirth (below IOMr: aOR .85; 95% CI .57-1.25; above IOMr: aOR 1.09; 95% CI .73-1.63). With regard to the effect of GWG according to both recommendations on indications for referral and birth outcomes, GWG above Tc was associated with higher rates of referral for hypertensive disorders (aOR 1.91; 95% CI 1.04-3.50) and for meconium stained liquor (aOR 2.22; CI 1.33-3.71) after adjusting for BMI and parity.

CONCLUSIONS

GWG above Tc - irrespective of BMI category - was associated with doubled odds of referral to specialist care during childbirth. GWG below or above IOMR and GWG below TC were not associated with adverse obstetric outcomes in women who were eligible for primary care at the outset of their pregnancy.

IMPLICATIONS FOR PRACTICE

weight gain <15kg between 12 and 36 weeks is advised for women in all BMI categories in this population. It is important to validate GWG guidelines in a target population before implementing them.

Child academic achievement in association with pre-pregnancy obesity and gestational weight gain

BACKGROUND

Recent data suggest that children of mothers who are obese before pregnancy, or who gain too much weight during pregnancy, may be at an increased risk of cognitive impairments.

METHODS

Mother-infant dyads enrolled in a birth cohort study in Pittsburgh, Pennsylvania (1983-1986), were followed from early pregnancy to 14 years postpartum (n=574). Math, reading and spelling achievements were assessed at ages 6 and 10 years using the Wide Range Achievement Test-Revised, and at age 14 years using the Wechsler Individual Achievement Test Screener. Self-reported total GWG was converted to gestational age-standardised z-scores. Generalised estimating equations were used to estimate the effects of GWG and pre-pregnancy body mass index (BMI) on academic achievement at 6, 10 and 14 years, while adjusting for maternal race, child sex, parity, employment, family income, maternal intelligence, maternal depression, pre-pregnancy BMI (in GWG models only) and the home environment.

RESULTS

The mean (SD) BMI was 23.4 (5.7) kg/m(2) and the mean (SD) GWG reported at delivery was 14.4 (5.9) kg. There was a significant non-linear association between pre-pregnancy BMI and an offspring's academic achievement. At 6, 10 and 14 years, an offspring's academic scores were inversely associated with pre-pregnancy BMI beyond 22 kg/m(2). High GWG (>1 SD) was associated with approximately 4-point lower reading (adjusted β (adjβ) -3.75, 95% CI -7.1 to -0.4) and spelling scores (adjβ -3.90, 95% CI -7.8 to -0.2), compared with GWG -1 to +1 SD.

CONCLUSIONS

Future studies in larger and socioeconomically diverse populations are needed to confirm maternal weight and weight gain as causal determinants of a child's academic skills, and whether this effect persists into adulthood.

Maternal pre-pregnancy BMI, gestational weight gain, and infant birth weight: A within-family analysis in the United States

In the United States, the high prevalence of unhealthy preconception body weight and inappropriate gestational weight gain among pregnant women is an important public health concern. However, the relationship among pre-pregnancy BMI, gestational weight gain, and newborn birth weight has not been well established. This study uses a very large dataset of sibling births and a within-family design to thoroughly address this issue. The baseline analysis controlling for mother fixed effects indicates maternal preconception overweight, preconception obesity, and excessive gestational weight gain significantly increase the risk of having a high birth weight baby, respectively, by 1.3, 3 and 3.9 percentage points, while underweight before pregnancy and inadequate gestational weight gain increase the low birth weight incidence by 1.4 and 2 percentage points. The benchmark results are robust in a variety of sensitivity checks. Since poor birth outcomes especially high birth weight and low birth weight have lasting adverse impacts on one's health, education, and socio-economic outcomes later in life, the findings of this research suggest promoting healthy weight among women before pregnancy and preventing inappropriate weight gain during pregnancy can generate significant intergenerational benefits.

Knowledge translation tool to improve pregnant women's awareness of gestational weight gain goals and risks of gaining outside recommendations: a non-randomized intervention study

Background

There is an urgent need to prevent excessive pregnancy weight gain, a contributor to both maternal and child obesity. However, the majority of women had reported not being counseled to gain an appropriate amount of gestational weight by their health care providers. We developed a knowledge translation (KT) tool designed to facilitate the clinical interaction between pregnant women and their health care providers (HCPs). We piloted the tool on the impact on women’s knowledge of gestational weight gain (GWG) goals, and evaluated its potential in promoting appropriate knowledge about GWG within the 2009 Institute of Medicine guidelines.

Methods

We conducted a prospective cohort study, comparing women’s knowledge about GWG after the KT tool to women from the same clinics and care providers the year prior. Our primary outcome was the proportion of women who reported receiving an appropriate GWG recommendation from their care provider. We evaluated knowledge on a survey conducted at enrollment in the cohort at ≤ 20 weeks gestation and evaluated participant satisfaction with the KT tool in the third trimester. We performed univariate and multivariable logistic regression analyses for differences in outcomes with historical controls from the same clinics. Our a priori sample size calculation required 130 participants to demonstrate a 15% increase in reported counseling about gestational weight gain.

Results

One hundred and forty-six women were recruited and 131 (90%) completed the enrollment survey. Women who received the KT tool were more likely to report receiving a specific GWG recommendation from their HCP (adjusted odds ratio [AOR] 3.45, 95% confidence interval [CI] 2.22-5.37) and discussing GWG topics with their HCP (AOR 7.96, 95% CI 4.41-14.37), and believing that there were risks to their infants with inadequate GWG (AOR 2.48, 95% CI 1.14-5.37). Half of women (49.5%) indicated that they would recommend the tool to a friend.

Conclusions

Women who received the KT tool reported receiving more counseling on GWG from their HCPs and were more aware of the risks of gaining outside appropriate GWG recommendations. The association between GWG education and GWG requires further research.

A review of the impact of dietary intakes in human pregnancy on infant birthweight

Studies assessing maternal dietary intakes and the relationship with birthweight are inconsistent, thus attempting to draw inferences on the role of maternal nutrition in determining the fetal growth trajectory is difficult. The aim of this review is to provide updated evidence from epidemiological and randomized controlled trials on the impact of dietary and supplemental intakes of omega-3 long-chain polyunsaturated fatty acids, zinc, folate, iron, calcium, and vitamin D, as well as dietary patterns, on infant birthweight. A comprehensive review of the literature was undertaken via the electronic databases Pubmed, Cochrane Library, and Medline. Included articles were those published in English, in scholarly journals, and which provided information about diet and nutrition during pregnancy and infant birthweight. There is insufficient evidence for omega-3 fatty acid supplements’ ability to reduce risk of low birthweight (LBW), and more robust evidence from studies supplementing with zinc, calcium, and/or vitamin D needs to be established. Iron supplementation appears to increase birthweight, particularly when there are increases in maternal hemoglobin concentrations in the third trimester. There is limited evidence supporting the use of folic acid supplements to reduce the risk for LBW; however, supplementation may increase birthweight by ~130 g. Consumption of whole foods such as fruit, vegetables, low-fat dairy, and lean meats throughout pregnancy appears beneficial for appropriate birthweight. Intervention studies with an understanding of optimal dietary patterns may provide promising results for both maternal and perinatal health. Outcomes from these studies will help determine what sort of dietary advice could be promoted to women during pregnancy in order to promote the best health for themselves and their baby.

Maternal height and the risk of preterm birth and low birth weight: a systematic review and meta-analyses

OBJECTIVE

Preterm birth (PTB) and low birth weight (LBW) are the leading causes of neonatal morbidity and mortality, but the effect of maternal height on these outcomes continues to be debated. Our objective was to determine the relationships between maternal height and PTB and LBW.

DATA SOURCES

Medline and EMBASE were searched from their inceptions.

STUDY SELECTION

Studies with a reference group that assessed the effect of maternal height on PTB (< 37 weeks) and LBW (< 2500 grams) in singletons were included.

DATA EXTRACTION

Data were extracted independently by two reviewers.

DATA SYNTHESIS

Fifty-six studies were included involving 333 505 women. In the cohort studies, the unadjusted risk of PTB in short-statured women was increased (relative risk [RR] 1.23; 95% CI 1.11 to 1.37), as was the unadjusted risk of LBW (RR 1.81; 95% CI 1.47 to 2.23), although not all of the studies with adjusted data found the same association. Maternal tall stature was not associated with PTB (unadjusted RR 0.97; 95% CI 0.82 to 1.14), although LBW was decreased (unadjusted RR 0.56; 95% CI 0.46 to 0.69), but not in the adjusted data.

CONCLUSION

From our complete systematic review and meta-analyses, to our knowledge the first in this area, we conclude that short-statured women have higher unadjusted risks of PTB and LBW and tall women have approximately one half the unadjusted risk of LBW of women of reference height.

Tertiary care availability and adolescent pregnancy characteristics in Saudi Arabia

BACKGROUND

In this study, we aimed to assess the rate of adolescent delivery in a Saudi tertiary health care center and to investigate the association between maternal age and fetal, neonatal, and maternal complications where a professional tertiary medical care service is provided.

METHODS

A cross-sectional study was performed between 2005 and 2010 at King Abdulaziz Medical City, Riyadh, Saudi Arabia. All primigravid Saudi women ≥24 weeks gestation, carrying a singleton pregnancy, aged <35 years, and with no chronic medical problems were eligible. Women were divided into three groups based on their age, ie, group 1 (G1) <16 years, group 2 (G2) ≥16 up to 19 years, and group 3 (G3) ≥19 up to 35 years. Data were collected from maternal and neonatal medical records. We calculated the association between the different age groups and maternal characteristics, as well as events and complications during the antenatal period, labor, and delivery.

RESULTS

The rates of adolescent delivery were 20.0 and 16.3 per 1,000 births in 2009 and 2010, respectively. Compared with G1 and G2 women, G3 women tended to have a higher body mass index, a longer first and second stage of labor, more blood loss at delivery, and a longer hospital stay. Compared with G1 and G2 women, respectively, G3 women had a 42% and a 67% increased risk of cesarean section, and had a 52% increased risk of instrumental delivery. G3 women were more likely to develop gestational diabetes or anemia, G2 women had a three-fold increased risk of premature delivery (odds ratio 2.81), and G3 neonates had a 50% increased overall risk of neonatal complications (odds ratio 0.51).

CONCLUSION

The adolescent birth rate appears to be low in central Saudi Arabia compared with other parts of the world. Excluding preterm delivery, adolescent delivery cared for in a tertiary health care center is not associated with a significantly increased medical risk to the mother, fetus, or neonate. The psychosocial effect of adolescent pregnancy and delivery needs to be assessed.

Pregnancy and Postpartum Related Weight Counseling Practices of U.S. Obstetrician-Gynecologists: Results from the Doc Styles Survey, 2010

OBJECTIVE

To describe factors and provider characteristics associated with weight-related counseling practices among U.S. obstetrician-gynecologists (OB/GYNs).

METHODS

Data were from a 2010 cross-sectional survey of 250 OB/GYNs. The OB/GYNs were asked how often they used pre-pregnancy body mass index (BMI) to determine the appropriate range of gestational weight gain (GWG), counseled pregnant patients on appropriate rate of GWG, and counseled postpartum patients on weight loss or maintenance. They were also asked how often they counseled pregnant and postpartum patients on five weight-related behaviors [consumption of Fruits and Vegetables (FV), Sugar-Sweetened Beverages (SSB), or high-fat or sugary foods, breastfeeding, and Physical Activity (PA)].

RESULTS

Less than half of providers reported "always" using BMI to determine appropriate GWG (42%); however 65% reported "always" counseling about appropriate GWG rate. About one-third of providers reported counseling about postpartum weight loss or maintenance (38%).Providers reported counseling pregnant and postpartum patients on all weight-related behaviors only 58% and 27% of the time, respectively. Providers with normal BMI had a greater odds of counseling pregnant patients on FV consumption (adjusted odds ratio (aOR): 3.2; 95% confidence interval (CI): 1.5-7.0) and postpartum patients on FV (aOR: 1.9; 95% CI: 1.1-3.6) compared to overweight/obese providers. Providers who exercised regularly had a greater odds of counseling pregnant and postpartum patients on SSB (aOR: 2.2; 95% CI: 1.1-4.8, and aOR: 2.6; 95% CI: 1.4-4.9, respectively) compared to those providers not exercising regularly. Providers who used podcasts for continuing medical education(CME) had a greater odds of providing counseling on several behaviors, including postpartum patients on FV consumption (aOR: 3.1; 95% CI: 1.3-7.2).

CONCLUSIONS

Improvements can be made in weight-related counseling practices of OB/GYNs for both pregnant and postpartum patients. Strategies to improve counseling practices, such as podcasts for CME, could be investigated further.

An epidemiological survey on low birth weight infants in China and analysis of outcomes of full-term low birth weight infants

BACKGROUND

Low birth weight (LBW) is one of the leading causes of adverse perinatal outcomes and is closely related to neonatal disease and death. The incidence of LBW has been increasing. The aim of this study was to investigate the current incidence rate and factors affecting low birth weight infants and perinatal outcomes of full-term low birth weight infants in mainland China.

METHODS

This paper describes a retrospective analysis of children born in 39 hospitals of different types in 14 different provinces, municipalities, and autonomous regions in seven districts within China throughout 2011. The data were first collected in hardcopy format and then entered into computer network databases. Data covering a total of 112,441 cases were collected. Cases were excluded if data were incomplete and in the case of miscarriage before 24 weeks of gestation, multiple pregnancies, or induction of labor due to fetal malformation, intrauterine death, and other reasons, leaving a total of 101,163 cases. SPSS 18.0 and SAS 9.2 statistical packages were used to analyze the collected data.

RESULTS

According to this research, the incidence of LBW in mainland China was 6.1%, which is higher than the 5.87% reported in 2000, and it varied across different areas. The incidence of LBW was significantly higher in tertiary care hospitals than in secondary care hospitals. LBW was found to be associated with maternal age of less than 20 years, low level of maternal education, previous histories of adverse pregnancies, and with pregnancy comorbidities and complications, such as hypertensive disorders during pregnancy, anemia, oligohydramnios, premature rupture of membranes, and gestational diabetes. The rates of stillbirths, severe neonatal asphyxia, and deaths among full-term LBW infants were 2.42%, 0.83%, and 3.49%, respectively. The rates of stillbirths and neonatal deaths among full-term LBW infants born by caesarean section were 0.5% and 1.0%, respectively, which was lower than vaginal delivery.

CONCLUSIONS

The incidence of LBW has increased in China. LBW is a leading cause of adverse pregnancy outcomes. Health care during pregnancy and management of high-risk factors for LBW may reduce the incidence of LWB and the death rate of LBW infants.

Maternal Weight Gain during Pregnancy and Somatic Classification of Neonates According to Birth Weight and Duration of Pregnancy Taking Account of Maternal Body Weight and Height

Background and Aim: The classification of weight gain during pregnancy and the somatic classification of neonates according to birth weight and duration of pregnancy can be done using percentile values. We aimed to compare such classifications using percentiles of the overall study population with classifications using percentiles that were calculated taking account of maternal height and weight. Material and Methods: Using data from the German Perinatal Survey (1995-2000, over 2.2 million singleton pregnancies) we classified weight gain during pregnancy as low (< 10th percentile), high (> 90th percentile), or medium (10th-90th percentile). Neonates were classified by birth weight as small for gestational age (SGA, < 10th percentile), large for gestational age (LGA, > 90th percentile), or appropriate for gestational age (AGA, 10th-90th percentile). Classifications were performed for 12 groups of women and their neonates formed according to maternal height and weight, either with the percentiles calculated from the total study population or with group-specific percentiles. Results: Using percentiles of the total study population there was large variability between the 12 groups in the proportions with low and high weight gain and in the proportions of SGA and LGA neonates. The variability was much lower when group-specific percentiles were used. Conclusions: Classifications of maternal weight gain during pregnancy and birth weight differ substantially, depending on whether percentiles calculated from the total study population or group-specific percentiles are used. The impact of using percentiles that take account of maternal anthropometric parameters for the medical care and health of neonates needs to be elucidated in future research.

Comparison of national gestational weight gain guidelines and energy intake recommendations

Although data showing adverse effects with high and low gestational weight gain (GWG) come from a large number of countries, a variety of guidelines about the GWG exist. Our objectives were to compare existing GWG and energy recommendations across various countries, as well as the rationale or evidence on which they were based. We used the United Nations' Human Developmental Index to determine the ranking of the country to ensure broad sampling and then searched for guidelines. We first searched the national government websites, and if necessary searched Medline and EMBASE, Global Health databases, and bibliographies of published articles for both guidelines and the studies on which they were based. We found guidelines for 31% of the countries, and 59% of these had a GWG recommendation, 68% had an energy intake recommendation (EIR), and 36% had both. About half of the GWG guidelines are similar to the 2009 American Institutes of Medicine (IOM) and 73% of the EIRs are similar to the 2006 IOM. Despite the documented relationship between both high GWG and adverse outcomes for women and infants and low GWG and adverse outcomes in infants, there are a wide variety of guidelines for GWG and energy recommendations by different countries around the world.

Uterine fibroids affect pregnancy outcome in women over 30 years old: role of other risk factors

OBJECTIVE

To evaluate the pregnancy outcome in women >30 years old with uterine fibroids also considering other possible concomitant risk factors.

METHODS

A multicentric, observational and retrospective study was conducted. All women were asked to complete a questionnaire while they were in hospital and the outcome of pregnancy was investigated.

RESULTS

Women with uterine fibroids before pregnancy were more frequently >35 years old and in their clinical history before pregnancy showed more pelvic pain, polliachiuria, previous pelvic surgery, hypermenorrhea and dysmenorrhea, than control women (p < 0.0001). During pregnancy patients with uterine fibroids showed significantly more threatened preterm birth (PTB) and PTB, weight gain, hyperemesis, gestational hypertension and post-partum bleeding and showed more often requirement for emergency cesarean section (p < 0.0001). The multivariate logistic regression model used for evaluating the effect of clinical parameters on outcome of pregnancy showed that age >35 years, pelvic pain, work, weight gain, hyperemesis, threatened miscarriage and threatened PTB were significantly correlated with unfavorable pregnancy outcome , independently of the presence of uterine fibroids (p < 0.0001).

CONCLUSIONS

The present study confirming a more frequent negative pregnancy outcome in presence of uterine fibroids, showed that other risk factors may affect pregnancy and delivery outcome in women aging >30 years old.