Dataset Information

Maternal Antioxidant Levels in Pregnancy and Risk of Preeclampsia and Small for Gestational Age Birth: A Systematic Review and Meta-Analysis.

ABSTRACT:

Background

Oxidative stress in preeclampsia and small for gestational age (SGA) birth suggests antioxidant supplementation could prevent these conditions. However, it remains unclear whether maternal antioxidant levels are systematically lower in these pregnancies.

Objective

To conduct a systematic review of the association between maternal antioxidant levels during pregnancy and preeclampsia or SGA.

Methods

We searched PubMed, Embase, and several other databases from 1970-2013 for observational studies that measured maternal blood levels of non-enzymatic antioxidants (vitamins A, C, E, and carotenoids) during pregnancy or within 72 hours of delivery. The entire review process was done in duplicate. Study quality was assessed using the Newcastle-Ottawa Scale and additional questions. We pooled the standardized mean difference (SMD) across studies, stratified by outcome and pregnancy trimester, and investigated heterogeneity using meta-regression.

Results

We reviewed 1,882 unique citations and 64 studies were included. Most studies were small with important risk of bias. Among studies that addressed preeclampsia (n = 58) and SGA (n = 9), 16% and 66%, respectively, measured levels prior to diagnosis. The SMDs for vitamins A, C, and E were significantly negative for overall preeclampsia, but not for mild or severe preeclampsia subtypes. Significant heterogeneity was observed in all meta-analyses and most could not be explained. Evidence for lower carotenoid antioxidants in preeclampsia and SGA was limited and inconclusive. Publication bias appears likely.

Conclusions

Small, low-quality studies limit conclusions that can be drawn from the available literature. Observational studies inconsistently show that vitamins C and E or other antioxidants are lower in women who develop preeclampsia or SGA. Reverse causality remains a possible explanation for associations observed. New clinical trials are not warranted in light of this evidence; however, additional rigorous observational studies measuring antioxidant levels before clinical detection of preeclampsia and SGA may clarify whether levels are altered at a causally-relevant time of pregnancy.

SUBMITTER: Cohen JM

PROVIDER: S-EPMC4527773 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Publications

Maternal Antioxidant Levels in Pregnancy and Risk of Preeclampsia and Small for Gestational Age Birth: A Systematic Review and Meta-Analysis.

Cohen Jacqueline M JM Beddaoui Margaret M Kramer Michael S MS Platt Robert W RW Basso Olga O Kahn Susan R SR

PloS one 20150806 8

<h4>Background</h4>Oxidative stress in preeclampsia and small for gestational age (SGA) birth suggests antioxidant supplementation could prevent these conditions. However, it remains unclear whether maternal antioxidant levels are systematically lower in these pregnancies.<h4>Objective</h4>To conduct a systematic review of the association between maternal antioxidant levels during pregnancy and preeclampsia or SGA.<h4>Methods</h4>We searched PubMed, Embase, and several other databases from 1970- ...[more]

PMID: 26247870

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Project description:BackgroundSub-optimal maternal lipid levels during pregnancy may be implicated in the pathophysiological mechanisms leading to low birth weight (LBW) and small-for-gestational-age (SGA). We aimed to determine whether maternal lipid levels across pregnancy were associated with birth weight and the risks of LBW and SGA in rural Gambia.MethodsThis secondary analysis of the ENID trial involved 573 pregnant women with term deliveries. Plasma levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), and triglycerides (TG) were analyzed at enrolment (mean (SD) = 13.9 (3.3) weeks gestation), 20 and 30 weeks gestation as continuous variables and percentile groups. Regression models with adjustment for confounders were used to examine associations between gestational lipid levels and birth weight and the risks of LBW (birth weight < 2500 g) and SGA (<10th percentile INTERGROWTH-21ST for birth weight).ResultsThere were 7.9% LBW and 32.5% SGA infants. At enrolment, every unit increase in HDL-c was associated with a 2.7% (P = 0.011) reduction in relative risk of LBW. At 20 weeks gestation, every unit increase in TC levels was associated with a 1.3% reduction in relative risk of LBW (P = 0.002). Low (<10th percentile) HDL-c at enrolment or at 20 weeks gestation was associated with a 2.6 (P = 0.007) and 3.0 (P = 0.003) times greater risk of LBW, respectively, compared with referent (10th─90th) HDL-c. High (>90th percentile) LDL-c at 30 weeks gestation was associated with a 55% lower risk of SGA compared with referent LDL-c (P = 0.017). Increased levels of TC (β = 1.3, P = 0.027) at 20 weeks gestation and of TC (β = 1.2, P = 0.006) and LDL-c (β = 1.5, P = 0.002) at 30 weeks gestation were all associated with higher birth weight.ConclusionsIn rural Gambia, lipid levels during pregnancy were associated with infant birth weight and the risks of LBW and SGA. Associations varied by lipid class and changed across pregnancy, indicating an adaptive process by which maternal lipids may influence fetal growth and birth outcomes.Trial registrationThis trial was registered as ISRCTN49285450 on: 12/11/2009.

Project description:BACKGROUND:Among highly exposed populations, arsenic exposure in utero may be associated with decreased birth weight, however less is known about potential effects of arsenic exposure in urban communities without contaminated sources such as drinking water. OBJECTIVE:Investigate the association of blood arsenic levels with birth weight-for-gestational age categories within a prospective birth cohort study. DESIGN/METHODS:We analyzed 730 mother-infant dyads within the Programming Research in Obesity, GRowth, Environment and Social Stressors (PROGRESS) cohort in Mexico City. Total arsenic was measured in maternal blood samples from the 2nd and 3rd trimesters, at delivery, as well as from infant umbilical cord blood samples. Multivariable, multinomial logistic regression models adjusting for maternal age at enrollment, pre-pregnancy body mass index, parity, infant sex, socioeconomic position, and prenatal environmental tobacco smoke exposure were used to calculate odds ratios of small-for-gestational age (<10th percentile, SGA) and large-for-gestational age (>90th percentile, LGA) compared to appropriate-for-gestational age (AGA) per unit increase of log-transformed arsenic. RESULTS:Median (IQR) blood arsenic levels for maternal second trimester were 0.72 (0.33) ?g/L, maternal third trimester 0.75 (0.41) ?g/L, maternal at delivery 0.85 (0.70) ?g/L, and infant cord 0.78 (0.65) ?g/L. Maternal delivery and infant cord blood samples were most strongly correlated (spearman r?=?0.65, p?<?0.0001). Maternal arsenic levels at delivery were associated with significantly higher odds of both SGA (adj. OR?=?1.44, 95% CI: 1.08-1.93) and LGA (adj. OR?=?2.03, 95% CI: 1.12-3.67) compared to AGA. Results were similar for cord blood. There were 130 SGA infants and 22 LGA infants. Earlier in pregnancy, there were no significant associations of arsenic and birth weight-for-gestational age. However, we observed non-significantly higher odds of LGA among women with higher arsenic levels in the 3rd trimester (adj. OR?=?1.46, 95% CI: 0.67-3.12). CONCLUSION:We found that in a Mexico City birth cohort, higher maternal blood arsenic levels at delivery were associated with higher odds of both SGA and LGA. However, sources and species of arsenic were not known and the number of LGA infants was small, limiting the interpretation of this finding and highlighting the importance of future large studies to incorporate arsenic speciation. If our findings were confirmed in studies that addressed these limitations, determining modifiable factors that could be mitigated, such as sources of arsenic exposure, may be important for optimizing fetal growth to improve long-term health of children.

Dataset Information

Maternal Antioxidant Levels in Pregnancy and Risk of Preeclampsia and Small for Gestational Age Birth: A Systematic Review and Meta-Analysis.

Background

Objective

Methods

Results

Conclusions

Publications

Maternal Antioxidant Levels in Pregnancy and Risk of Preeclampsia and Small for Gestational Age Birth: A Systematic Review and Meta-Analysis.

Similar Datasets

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