Dataset Information

Maternal Anemia and Low Birth Weight: A Systematic Review and Meta-Analysis.

ABSTRACT:

Objective

To systematically analyze the relationship between maternal anemia and low birth weight.

Methods

A search of studies was conducted in the main databases (Medline, Embase, Scopus, Web of Science, SciELO, and Lilacs), the gray literature, and the reference lists of selected articles. Cohort and case-control studies that met the eligibility criteria were included in the review. There was no limitation on the language or date of publication. Article selection and data extraction were performed by two independent reviewers. Meta-analyses with random effects, subgroup analyses and meta-regressions were performed. Publication bias was measured using Egger regression and visual funnel plot inspection.

Results

A total of 7243 articles were found, of which 71 comprised the systematic review and 68 were included in the meta-analyses. Maternal anemia was associated with low birth weight with an adjusted OR: 1.23 (95% CI: 1.06⁻1.43) and I²: 58%. The meta-regressions confirmed that the sample size and the methodological quality may partially explain the statistical heterogeneity.

Conclusions

Maternal anemia was considered a risk factor for low birth weight.

SUBMITTER: Figueiredo ACMG

PROVIDER: S-EPMC5986481 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Maternal Anemia and Low Birth Weight: A Systematic Review and Meta-Analysis.

Figueiredo Ana C M G ACMG Gomes-Filho Isaac S IS Silva Roberta B RB Pereira Priscilla P S PPS Mata Fabiana A F Da FAFD Lyrio Amanda O AO Souza Elivan S ES Cruz Simone S SS Pereira Mauricio G MG

Nutrients 20180512 5

<h4>Objective</h4>To systematically analyze the relationship between maternal anemia and low birth weight.<h4>Methods</h4>A search of studies was conducted in the main databases (Medline, Embase, Scopus, Web of Science, SciELO, and Lilacs), the gray literature, and the reference lists of selected articles. Cohort and case-control studies that met the eligibility criteria were included in the review. There was no limitation on the language or date of publication. Article selection and data extrac ...[more]

PMID: 29757207

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Project description:BackgroundAnemia in pregnancy has been associated with a number of adverse birth outcomes, such as low birth weight (LBW) or preterm birth (PTB). However, the evidence from primary studies on anemia in pregnancy with LBW and PTB is contentious. Moreover, a systematic review and meta-analysis to summarize these findings have not been conducted for Ethiopia. This study aimed to synthesize the best available evidence and quantify the strength and direction of the association of anemia in Ethiopia.MethodsThis review examined women with singleton pregnancies with low birth weight (LBW) and preterm birth (PTB). We retrieved studies from PubMed, Wiley, Cochrane databases, and Google Scholar from inception to February 2, 2024. The World Health Organization (WHO) defines anemia in pregnancy as a low blood haemoglobin (Hgb) concentration below 11 g/dl or a hematocrit level of < 33%. When the newborn's weight was below 2500 g, LBW was considered. Preterm birth refers to the birth of a baby before 37 completed weeks of gestation. Meta-analysis was conducted using fixed and random effects models. The degree of heterogeneity, publication bias, and quality of the evidence of studies was assessed.ResultsThere were 35 and 8 studies, with 14,319 and 3,265 respondents included in the meta-analysis for LBW and PTB, respectively. Neonates born to women who had normal Hgb levels were less likely to be LBW [pooled odds ratio (POR) = 0.22, 95% CI: (0.17, 0.28); I2 = 80%] (low-quality evidence). Neonates born to women with normal Hgb levels had a lower risk of PTB [POR = 0.22, 95% CI: 0.18, 0.28; I2 = 19%] (very low-quality evidence). The effect size estimate remained significant after sub-group analysis based on study design and province, except in two retrospective cohort studies for LBW.ConclusionThe findings suggest major implications for strengthening the implementation of nutrition policies to prevent anemia during pregnancy in Ethiopia. Further research is warranted to assess interventions that are effective in combating maternal anemia to reduce rates of LBW and PTB.

Project description:IntroductionLow birth weight (LBW) is an important general health indicator. The present study was conducted to evaluate the prevalence and risk factors of LBW in Iran.MethodThis meta-analysis was reported based on the PRISMA guidelines. All stages were independently performed by two authors. This review is registered with PROSPERO (CRD42020163446). We searched epidemiological studies at international databases of Scopus, Embase, Science Direct, PubMed/Medline, CINAHL, EBSCO, Cochrane Library, Web of Science, and Google Scholar search engine, as well as Iranian databases of SID, IranDoc, Iranian National Library, Barakat Knowledge Network System, RICST and Magiran using MeSH keywords without time limit until 2019. After selecting the studies, applying the inclusion and exclusion criteria, data extraction and qualitative assessment, the data were analyzed based on random effects model using Comprehensive Meta-Analysis Software version 2. P < 0.05 was considered significant.ResultsThe prevalence of LBW in Iran was 7.95% (95% confidence interval [CI]: 7.36-8.58) in 62 studies with a sample size of 301,839 newborns. The prevalence of LBW in girls and boys was 8.41% (95%CI: 7.47-9.45) and 6.67% (95%CI: 5.86-7.59), respectively. The girls-to-boys odds ratio of LBW was 1.25 (95%CI: 1.13-1.39, P < 0.001) very LBW and extremely LBW prevalence was estimated to be 0.61% (95%CI: 0.40-0.93) and 0.29% (95% CI: 0.18-0.45), respectively. The risk factors for LBW were age of >35 versus [vs.] ≤35 (P = 0.024), age of <18 vs. ≥18 (P < 0.001), education of middle school and lower vs. high school and higher (P < 0.001), weight under 50 kg (P = 0.001), employed vs. housekeeper (P < 0.001), inadequate prenatal care (P = 0.046), interval with previous pregnancy <2 vs. >2 (P < 0.001), prematurity (P < 0.001), history of LBW (P < 0.001), multiple birth (P < 0.001), abortion (P < 0.001), vaginal bleeding (P < 0.001), hypertension (P = 0.001) and preeclampsia (P < 0.001).ConclusionThe results of this meta-analysis showed that LBW is prevalent in Iran. This study can be a national database for LBW that would be of interest to Iranian health policy-makers and planners.

Project description:To evaluate the relationships between maternal particulate matter exposure and offspring birth weight. Studies were categorized into three subgroups: term low birth weight (TLBW) among full-term births and all births (regardless of gestational age) and low birth weight (LBW) among all births, based on the search results of MEDLINE and the Web of Science from the inception of the database to April 2022. Subgroup analyses were conducted based on the economic status, region, exposure assessment, risk of bias, and adjustment. Sixty-one studies involving 34,506,975 singleton live births in 15 countries were analyzed. Overall, the risk of bias for most studies (75%) was low. In 39 of 47 term birth studies, the pooled odds ratio of TLBW among term births for per interquartile range (IQR) increases throughout the entire pregnancy was 1.02 (1.01 to 1.03) for PM2.5 and 1.03 (1.01 to 1.05) for PM10 after adjustment for covariates. No significant relevance was detected across each trimester period for PM2.5. A stronger effect was observed during the second trimester (1.03, 1.01 to 1.06) for PM10. There was no increased risk of TLBW in all births associated with IQR increases in PM2.5 and PM10. LBW was associated with PM2.5 exposure in 4 of 7 studies, but statistical heterogeneity was considerable. In the TLBW subgroup analysis, the effects of PM2.5 and PM10 were both greater in studies conducted in advanced countries, studies with low bias, and studies that adjusted for maternal age, infant sex, and parity. Stronger effects were present for PM2.5 exposure collected from monitoring stations and PM10 exposure interpolated from the inverse distance weighting model. TLBW may be associated with prenatal exposure to particulate matter, but no critical windows were identified. Stronger associations were observed in advanced countries. Future original study designs need to consider the impact of different exposure assessment modalities and all possible confounding factors.

Project description:ImportanceNeonatal anemia has a long-term effect on children's growth and development. Anemia during pregnancy is also the most widespread nutritional deficiency among pregnant women in the world; If it leads to anemia in newborns, it will affect a wide range of people and be a public health problem worthy of attention.ObjectiveTo study the relationship between maternal anemia during pregnancy and neonatal hemoglobin levels.Data sourcesPubMed, Web of science, Scopus, MEDLINE, Embase, ProQuest, Dissertations & Theses Global, The Cochrane Library, China Biology Medicine Database, Chinese CNKI Database, and Chinese Wanfang Database were systematically searched from inception to August 31, 2022.Study selectionThe meta-analysis included all original studies which pertain to cohort studies, case-control studies or cross-sectional studies that investigated the relationship between maternal anemia during pregnancy and neonatal hemoglobin levels.Data extraction and synthesisHemoglobin level of both anemic and non-anemic pregnant mothers and their paired newborns were pooled from the selected studies. The random-effects model was used to assess the risk of getting a lower neonatal hemoglobin level between mothers with and without pregnant anemia. Data analyses were performed from September 5, 2022, to March 10, 2023.Main outcomes and measuresMaternal anemia during pregnancy is a risk factor of lower neonatal hemoglobin levels.ResultsThe initial search yielded 4267 records of which 116 articles underwent full-text evaluation, which identified 18 articles and a total of 1873 patients that were included. The findings of the meta-analysis showed a significant difference between the two groups(MD=-1.38; 95%CI:[-1.96,-0.80]. p<0.01), while the co-effect showed that the neonatal hemoglobin value of anemic mothers was 1.38g/dL lower than that of non-anemic mothers(-1.96,-0.80), suggesting a correlation between maternal anemia lower neonatal hemoglobin levels.Conclusions and relevanceThis systematic review and meta-analysis demonstrated that maternal anemia during pregnancy were associated with a lower level of newborn hemoglobin levels. This may enable a better understanding of neonatal anemia and provide guidance towards future development of nutritional supplementation during pregnancy and the prediction of postpartum outcomes.Trial registrationPROSPERO Identifier: CRD42022352759.

Project description:ObjectiveTo assess whether exposure to high temperatures in pregnancy is associated with increased risk for preterm birth, low birth weight, and stillbirth.DesignSystematic review and random effects meta-analysis.Data sourcesMedline and Web of Science searched up to September 2018, updated in August 2019.Eligibility criteria for selecting studiesClinical studies on associations between high environmental temperatures, and preterm birth, birth weight, and stillbirths.Results14 880 records and 175 full text articles were screened. 70 studies were included, set in 27 countries, seven of which were countries with low or middle income. In 40 of 47 studies, preterm births were more common at higher than lower temperatures. Exposures were classified as heatwaves, 1°C increments, and temperature threshold cutoff points. In random effects meta-analysis, odds of a preterm birth rose 1.05-fold (95% confidence interval 1.03 to 1.07) per 1°C increase in temperature and 1.16-fold (1.10 to 1.23) during heatwaves. Higher temperature was associated with reduced birth weight in 18 of 28 studies, with considerable statistical heterogeneity. Eight studies on stillbirths all showed associations between temperature and stillbirth, with stillbirths increasing 1.05-fold (1.01 to 1.08) per 1°C rise in temperature. Associations between temperature and outcomes were largest among women in lower socioeconomic groups and at age extremes. The multiple temperature metrics and lag analyses limited comparison between studies and settings.ConclusionsAlthough summary effect sizes are relatively small, heat exposures are common and the outcomes are important determinants of population health. Linkages between socioeconomic status and study outcomes suggest that risks might be largest in low and middle income countries. Temperature rises with global warming could have major implications for child health.Systematic review registrationPROSPERO CRD 42019140136 and CRD 42018118113.

Dataset Information

Maternal Anemia and Low Birth Weight: A Systematic Review and Meta-Analysis.

Objective

Methods

Results

Conclusions

Publications

Maternal Anemia and Low Birth Weight: A Systematic Review and Meta-Analysis.

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