Dataset Information

Maternal influenza and birth outcomes: systematic review of comparative studies.

ABSTRACT:

Background

Although pregnant women are considered at high risk for severe influenza disease, comparative studies of maternal influenza and birth outcomes have not been comprehensively summarised.

Objective

To review comparative studies evaluating maternal influenza disease and birth outcomes.

Search strategy

We searched bibliographic databases from inception to December 2014.

Selection criteria

Studies of preterm birth, small-for-gestational-age (SGA) birth or fetal death, comparing women with and without clinical influenza illness or laboratory-confirmed influenza infection during pregnancy.

Data collection and analysis

Two reviewers independently abstracted data and assessed study quality.

Main results

Heterogeneity across 16 studies reporting preterm birth precluded meta-analysis. In a subgroup of the highest-quality studies, two reported significantly increased preterm birth (risk ratios (RR) from 2.4 to 4.0) following severe 2009 pandemic H1N1 (pH1N1) influenza illness, whereas those assessing mild-to-moderate pH1N1 or seasonal influenza found no association. Five studies of SGA birth showed no discernible patterns with respect to influenza disease severity (pooled odds ratio 1.24; 95% CI 0.96-1.59). Two fetal death studies were of sufficient quality and size to permit meaningful interpretation. Both reported an increased risk of fetal death following maternal pH1N1 disease (RR 1.9 for mild-to-moderate disease and 4.2 for severe disease).

Conclusions

Comparative studies of preterm birth, SGA birth and fetal death following maternal influenza disease are limited in number and quality. An association between severe pH1N1 disease and preterm birth and fetal death was reported by several studies; however, these limited data do not permit firm conclusions on the magnitude of any association.

Tweetable abstract

Comparative studies are limited in quality but suggest severe pandemic H1N1 influenza increases preterm birth.

SUBMITTER: Fell DB

PROVIDER: S-EPMC5216449 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Maternal influenza and birth outcomes: systematic review of comparative studies.

Fell D B DB Savitz D A DA Kramer M S MS Gessner B D BD Katz M A MA Knight M M Luteijn J M JM Marshall H H Bhat N N Gravett M G MG Skidmore B B Ortiz J R JR

BJOG : an international journal of obstetrics and gynaecology 20160606 1

<h4>Background</h4>Although pregnant women are considered at high risk for severe influenza disease, comparative studies of maternal influenza and birth outcomes have not been comprehensively summarised.<h4>Objective</h4>To review comparative studies evaluating maternal influenza disease and birth outcomes.<h4>Search strategy</h4>We searched bibliographic databases from inception to December 2014.<h4>Selection criteria</h4>Studies of preterm birth, small-for-gestational-age (SGA) birth or fetal ...[more]

PMID: 27264387

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Project description:BackgroundAlthough pregnant women are a priority group for influenza vaccination, its effect on birth outcomes has long been debated. Numerous observational studies and a few randomized controlled studies have been conducted, with inconsistent results.ObjectivesTo evaluate the association of influenza vaccination in pregnancy with adverse birth outcomes.Data sourceThe Cochrane Library, PubMed, EMBASE, Web of Science, and Scopus were searched.Study eligibility criteriaThis analysis included randomized placebo-controlled studies, cohort studies, and case-control studies, in which inactivated influenza vaccination was given during pregnancy and fetal adverse birth outcomes were assessed.Participants & interventionWomen who received inactivated influenza vaccine during pregnancy and their offspring.Study appraisal and synthesisTwo independent reviewers and a third reviewer collaborated in study selection and data extraction. A Bayesian 3-level random-effects model was utilized to assess the impact of maternal influenza vaccination on birth outcomes, which were presented as odds ratios (ORs) with 95% credible interval (CrIs). Bayesian outcome probabilities (P) of an OR<1 were calculated, and values of at least 90% (0.9) were deemed to indicate a significant result.ResultsAmong the 6,249 identified publications, 48 studies were eligible for the meta-analysis, including 2 randomized controlled trials, 41 cohort studies, and 5 case-control studies. The risk of none of the following adverse birth outcomes decreased significantly: preterm birth (OR = 0.945, 95% CrI: 0.736-1.345, P = 73.3%), low birth weight (OR = 0.928, 95% CrI: 0.432-2.112, P = 76.7%), small for gestational age (OR = 0.971, 95% CrI: 0.249-4.217,P = 63.3%), congenital malformation (OR = 1.026, 95% CrI: 0.687-1.600, P = 38.0%), and fetal death (OR = 0.942, 95% CrI: 0.560-1.954, P = 61.6%). Summary estimates including only cohort studies showed significantly decreased risks for preterm birth, small for gestational age and fetal death. However, after adjusting for season at the time of vaccination and countries' income level, only fetal death remained significant.ConclusionThis Bayesian meta-analysis did not find a protective effect of maternal influenza vaccination against adverse birth outcomes, as reported in previous studies. In fact, our results showed evidence of null associations between maternal influenza vaccination and adverse birth outcomes.

Project description:BackgroundThree previous reviews on the association of vitamin D insufficiency in pregnancy with preterm birth (PTB) and stillbirth were limited in scope and deemed inconclusive. With important new evidence accumulating, there is the need to update the previous estimates and assess evidence on other clinically important outcomes such as spontaneous abortion and Apgar score. We conducted a systematic review and meta-analysis to evaluate the quality and strength of the available evidence on the relations between vitamin D nutritional status, and pregnancy and birth outcomes.MethodsPubMed and Scopus databases were searched from their inception to June, 2015 with no language restrictions imposed. Eighteen longitudinal studies satisfied the inclusion criteria. Random effects model was applied in computing the summary effect estimates and their corresponding 95% confidence intervals.ResultsSerum 25(OH)D levels <75 nmol/l was associated with 83% (95% CI: 1.23, 2.74) and 13% (95% CI: 0.94, 1.36) increased risk of PTB measured at <32-34 weeks and <35-37 weeks, respectively. An inverse dose-response relation was observed for both PTB outcome. Serum 25(OH)D levels <75 nmol/l was also associated with 11% increased risk of spontaneous PTB (<35-37 weeks; RR = 1.11; 95% CI: 0.75, 1.65) with a dose-response relation also noted. Vitamin D insufficiency was not associated with risk of spontaneous abortion and stillbirth (RR of 1.04 [95% CI: 0.95, 1.13] and 1.02 [95% CI: 0.96, 1.09], respectively), as well as short gestational length (ES = -0.24, 95% CI: -0.69, 0.22), and low Apgar score.ConclusionsWe found vitamin D insufficiency to be associated with risk of PTB. Regarding spontaneous abortion and stillbirth, the available evidence suggest no association with low vitamin D levels. The evidence on vitamin D nutrition and Apgar score is conflicting and controversial. Overall, the experimental evidence uncovered was small and weak. Hence, the benefits of vitamin D supplementation during pregnancy should be further evaluated through rigorous intervention studies.

Project description:BackgroundAntenatal corticosteroids (ACS) are highly effective at improving outcomes for preterm newborns. Evidence suggests the benefits of ACS may vary with the time interval between administration-to-birth. However, the optimal ACS administration-to-birth interval is not yet known. In this systematic review, we synthesised available evidence on the relationship between ACS administration-to-birth interval and maternal and newborn outcomes.MethodsThis review was registered with PROSPERO (CRD42021253379). We searched Medline, Embase, CINAHL, Cochrane Library, Global Index Medicus on 11 Nov 2022 with no date or language restrictions. Randomised and non-randomised studies of pregnant women receiving ACS for preterm birth where maternal and newborn outcomes were reported for different administration-to-birth intervals were eligible. Eligibility screening, data extraction and risk of bias assessment were performed by two authors independently. Fetal and neonatal outcomes included perinatal and neonatal mortality, preterm birth-related morbidity outcomes and mean birthweight. Maternal outcomes included chorioamnionitis, maternal mortality, endometritis, and maternal intensive care unit admission.FindingsTen trials (4592 women; 5018 neonates), 45 cohort studies (at least 22,992 women; 30,974 neonates) and two case-control studies (355 women; 360 neonates) met the eligibility criteria. Across studies, 37 different time interval combinations were identified. There was considerable heterogeneity in included administration-to-birth intervals and populations. The odds of neonatal mortality, respiratory distress syndrome and intraventricular haemorrhage were associated with the ACS administration-to-birth interval. However, the interval associated with the greatest improvements in newborn outcomes was not consistent across studies. No reliable data were available for maternal outcomes, though odds of chorioamnionitis might be associated with longer intervals.IntepretationAn optimal ACS administration-to-birth interval likely exists, however variations in study design limit identification of this interval from available evidence. Future research should consider advanced analysis techniques such as individual patient data meta-analysis to identify which ACS administration-to-birth intervals are most beneficial, and how these benefits can be optimised for women and newborns.FundingThis study was conducted with funding support from the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Sexual and Reproductive Health and Research (SRH), a co-sponsored programme executed by the World Health Organization.

Project description:BACKGROUND:We systematically reviewed and chronicled exposures and outcomes measured in the maternal and birth cohort studies in the Gulf Cooperation Council (GCC) countries and quantitatively summarized the weighted effect estimates between maternal obesity and (1) cesarean section (CS) and (2) fetal macrosomia. METHODS:We searched MEDLINE-PubMed, Embase, Cochrane Library, Scopus, and Web of Science electronic databases up to 30 June 2019. We considered all maternal and birth cohort studies conducted in the six GCC countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates (UAE)). We categorized cohort studies on the basis of the exposure(s) (anthropometric, environmental, medical, maternal/reproductive, perinatal, or socioeconomic) and outcome(s) (maternal or birth) being measured. Adjusted weighted effect estimates, in the form of relative risks, between maternal obesity and CS and fetal macrosomia were generated using a random-effects model. RESULTS:Of 3502 citations, 81 published cohort studies were included. One cohort study was in Bahrain, eight in Kuwait, seven in Qatar, six in Oman, 52 in Saudi Arabia, and seven in the UAE. Majority of the exposures studied were maternal/reproductive (65.2%) or medical (39.5%). Birth and maternal outcomes were reported in 82.7% and in 74.1% of the cohort studies, respectively. In Saudi Arabia, babies born to obese women were at a higher risk of macrosomia (adjusted relative risk (aRR), 1.15; 95% confidence interval (CI), 1.10-1.20; I2 =?50%) or cesarean section (aRR, 1.21; 95% CI, 1.15-1.26; I2 =?62.0%). Several cohort studies were only descriptive without reporting the magnitude of the effect estimate between the assessed exposures and outcomes. CONCLUSIONS:Cohort studies in the GCC have predominantly focused on reproductive and medical exposures. Obese pregnant women are at an increased risk of undergoing CS delivery or macrosomic births. Longer-term studies that explore a wider range of environmental and biological exposures and outcomes relevant to the GCC region are needed. SYSTEMATIC REVIEW REGISTRATION:PROSPERO CRD42017068910.

Project description:In pregnancy, iron deficiency and iron overload increase the risk for adverse pregnancy outcomes, but the effects of maternal iron status on long-term child health are poorly understood. The aim of the study was to systematically review and analyze the literature on maternal iron status in pregnancy and long-term outcomes in the offspring after birth. We report a systematic review on maternal iron status during pregnancy in relation to child health outcomes after birth, from database inception until 21 January 2021, with methodological quality rating (Newcastle-Ottawa tool) and random-effect meta-analysis. (PROSPERO, CRD42020162202). The search identified 8139 studies, of which 44 were included, describing 12,7849 mother-child pairs. Heterogeneity amongst the studies was strong. Methodological quality was predominantly moderate to high. Iron status was measured usually late in pregnancy. The majority of studies compared categories based on maternal ferritin, however, definitions of iron deficiency differed across studies. The follow-up period was predominantly limited to infancy. Fifteen studies reported outcomes on child iron status or hemoglobin, 20 on neurodevelopmental outcomes, and the remainder on a variety of other outcomes. In half of the studies, low maternal iron status or iron deficiency was associated with adverse outcomes in children. Meta-analyses showed an association of maternal ferritin with child soluble transferrin receptor concentrations, though child ferritin, transferrin saturation, or hemoglobin values showed no consistent association. Studies on maternal iron status above normal, or iron excess, suggest deleterious effects on infant growth, cognition, and childhood Type 1 diabetes. Maternal iron status in pregnancy was not consistently associated with child iron status after birth. The very heterogeneous set of studies suggests detrimental effects of iron deficiency, and possibly also of overload, on other outcomes including child neurodevelopment. Studies are needed to determine clinically meaningful definitions of iron deficiency and overload in pregnancy.

Dataset Information

Maternal influenza and birth outcomes: systematic review of comparative studies.

Background

Objective

Search strategy

Selection criteria

Data collection and analysis

Main results

Conclusions

Tweetable abstract

Publications

Maternal influenza and birth outcomes: systematic review of comparative studies.

Similar Datasets

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