Shu-Qin Wei

Maternal vitamin D status and adverse pregnancy outcomes: a systematic review and meta-analysis

Abstract Objective: To estimate the associations between maternal vitamin D status and adverse pregnancy outcomes. Study design: We searched electronic databases of the human literature in PubMed, EMBASE and the Cochrane Library up to October, 2012 using the following keywords: “vitamin D” and “status” or “deficiency” or “insufficiency” and “pregnancy”. A systematic review and meta-analysis were conducted on observational studies that reported the association between maternal blood vitamin D levels and adverse pregnancy outcomes including preeclampsia, gestational diabetes mellitus (GDM), preterm birth or small-for-gestational age (SGA). Results: Twenty-four studies met the inclusion criteria. Women with circulating 25-hydroxyvitamin D [25(OH)D] level less than 50 nmol/l in pregnancy experienced an increased risk of preeclampsia [odds ratio (OR) 2.09 (95% confidence intervals 1.50–2.90)], GDM [OR 1.38 (1.12–1.70)], preterm birth [OR 1.58 (1.08–2.31)] and SGA [OR 1.52 (1.08–2.15)]. Conclusion: Low maternal vitamin D levels in pregnancy may be associated with an increased risk of preeclampsia, GDM, preterm birth and SGA.

Inflammatory cytokines and spontaneous preterm birth in asymptomatic women: a systematic review.

OBJECTIVE: To estimate the association between inflammatory cytokines and the risk of spontaneous preterm birth in asymptomatic women. DATA SOURCES: We searched electronic databases of the human literature in PubMed, EMBASE, and the Cochrane Library up to February 2010 using the following key words: “preterm/pre-term + (birth/delivery)” and “cytokine” or “inflammation/inflammatory + marker/biomarker.” METHODS OF STUDY SELECTION: We included observational studies that reported the association between common inflammatory cytokines and spontaneous preterm birth as an outcome in asymptomatic women. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using fixed and random effects models. TABULATION, INTEGRATION, AND RESULTS: Seventeen primary studies comprising 6,270 participants met the inclusion criteria. Spontaneous preterm birth was strongly associated with increased levels of interleukin-6 (IL-6) in midtrimester cervicovaginal fluid (OR 3.05, 95% CI 2.00-4.67) (number needed to treat=7 for identifying an additional preterm delivery) and amniotic fluid (OR 4.52, 95% CI 2.67-7.65) (number needed to treat=7), but there was no association in plasma specimen (OR 1.5, 95% CI 0.7-3.0). Spontaneous preterm birth was strongly associated with increased C-reactive protein (CRP) levels in midtrimester amniotic fluid (OR 7.85, 95% CI 3.88-15.87) (number needed to treat=3), but the association was weak in plasma specimen (OR 1.53, 95% CI 1.22-1.90). There were insufficient data (fewer than three studies) for meta-analysis in other inflammatory cytokines. CONCLUSION: Inflammatory cytokine IL-6 in cervicovaginal fluid and IL-6 and CRP in amniotic fluid but not in plasma are strongly associated with spontaneous preterm birth in asymptomatic women, suggesting that inflammation at the maternal-fetal interface, rather than systemic inflammation, may play a major role in the etiology of such spontaneous preterm births.

An international trial of antioxidants in the prevention of preeclampsia (INTAPP).

OBJECTIVE We sought to investigate whether prenatal vitamin C and E supplementation reduces the incidence of gestational hypertension (GH) and its adverse conditions among high- and low-risk women. STUDY DESIGN In a multicenter randomized controlled trial, women were stratified by the risk status and assigned to daily treatment (1 g vitamin C and 400 IU vitamin E) or placebo. The primary outcome was GH and its adverse conditions. RESULTS Of the 2647 women randomized, 2363 were included in the analysis. There was no difference in the risk of GH and its adverse conditions between groups (relative risk, 0.99; 95% confidence interval, 0.78-1.26). However, vitamins C and E increased the risk of fetal loss or perinatal death (nonprespecified) as well as preterm prelabor rupture of membranes. CONCLUSION Vitamin C and E supplementation did not reduce the rate of preeclampsia or GH, but increased the risk of fetal loss or perinatal death and preterm prelabor rupture of membranes.

Longitudinal vitamin D status in pregnancy and the risk of pre-eclampsia

Please cite this paper as: Dr Wei SQ, Audibert F, Hidiroglou N, Sarafin K, Julien P, Wu Y, Luo ZC, Fraser WD. Longitudinal vitamin D status in pregnancy and the risk of pre‐eclampsia. BJOG 2012;119:832–839.

The effect of early oxytocin augmentation in labor: a meta-analysis

OBJECTIVE: To estimate the effects of early augmentation with oxytocin for slow progress of labor on the delivery method and on indicators of maternal and neonatal morbidity. DATA SOURCES: We conducted electronic database searches of PubMed, MEDLINE, EMBASE, and the Cochrane Library for articles published through February 2009 using the keywords “oxytocin,” “augmentation,” “active management of labor,” “cesarean section,” and “labor.” Primary authors were contacted directly if the data sought were unavailable. METHODS OF STUDY SELECTION: We included randomized controlled trials comparing early oxytocin augmentation with a more conservative approach to care in labor. We included only those studies in which membrane management was similar in the two groups. Early oxytocin augmentation was defined as immediate oxytocin administration when dystocia was identified. Data were extracted by two authors independently and evaluated for potential sources of bias. Relative risk (RR) and 95% confidence interval (CI) were calculated using fixed and random effects models. TABULATION, INTEGRATION, AND RESULTS: Nine trials with 1,983 women met the inclusion criteria. Early oxytocin was associated with an increase in the probability of spontaneous vaginal delivery (RR 1.09, 95% CI 1.03–1.17). For every 20 patients treated with early oxytocin augmentation, one additional spontaneous vaginal delivery is expected. Although the point estimate for the effect on cesarean delivery (RR 0.87, 95% CI 0.71–1.06) and on operative vaginal delivery (RR 0.84, 95% CI 0.70–1.00) showed modest protective effects, the CIs for both estimates included the null effect. A decrease in antibiotic use (RR 0.45, 95% CI 0.21–0.99) was observed with early intervention. Early oxytocin was associated with an increased risk of hyperstimulation (RR 2.90, 95% CI 1.21–6.94) without evidence of adverse neonatal effects. Women in the early oxytocin group reported higher levels of pain and discomfort in labor. CONCLUSION: Early oxytocin for augmentation in labor is associated with an increase in spontaneous vaginal delivery.

Role of nutrition in the risk of preeclampsia

Preeclampsia (PE) accounts for about one-quarter of the cases of maternal mortality and ranks second among the causes of pregnancy-associated maternal deaths in Canada and worldwide. The identification of an effective strategy to prevent PE is a priority and a challenge for research in obstetrics. Progress has been hampered by inadequate understanding of the underlying etiology of the disease. The role of maternal diet in the etiology of PE has recently received increased attention. The objective of this paper is to provide an overview of the literature concerning 1) the current understanding of the pathogenesis of PE, 2) the biological plausibility and potential mechanisms underlying the associations between maternal dietary exposures, nutrition, and the risk of PE, and 3) the epidemiological findings of maternal nutrient intake in relation to the risk of PE.

Absorption, transport, and bioavailability of vitamin e and its role in pregnant women.

Vitamin E is an important lipophilic antioxidant. The term refers to eight essential naturally occurring fat-soluble nutrients called tocopherols or tocotrienols. Among these isomers, alpha-tocopherol has the highest biologically active form and is found in all lipoprotein fractions. Vitamin E deficiency during pregnancy may cause miscarriage, preterm birth, preeclampsia, and intrauterine growth restriction. This review highlights recent findings that have led to a better understanding of vitamin E absorption, transport, bioavailability, and its role in pregnancy, and that underline the need for re-evaluation of the potential benefits of vitamin E supplementation in pregnant women.

In vitro evaluation of enhancing effect of borneol on transcorneal permeation of compounds with different hydrophilicities and molecular sizes

To investigate the enhancing effect of borneol on transcorneal permeation of compounds with different hydrophilicities and molecular sizes. Six compounds, namely rhodamine B, sodium-fluorescein, fluorescein isothiocyanate (FITC) dextrans of 4, 10, 20 and 40 kDa were selected as model drugs. Permeation studies were performed using excised cornea of rabbits by a Franz-type diffusion apparatus. The safety of borneol was assessed on the basis of corneal hydration level and Draize eye test. The application of 0.2% borneol to the cornea increased the apparent permeability coefficient by 1.82-(P<0.05), 2.49-(P<0.05), 4.18-(P<0.05) and 1.11-fold (not significant) for rhodamine B, sodium-fluorescein, FITC-dextrans of 4 and 10 kDa, respectively. No significant permeability enhancement of FITC dextrans of 10, 20 and 40 kDa with borneol was found compared to control. The permeability coefficient enhanced by 0.2% borneol was linear correlated to the molecular weight of model drugs (R(2)=0.9976). With the 0.05%, 0.1% and 0.2% borneol application, the corneal hydration values were <83% and Draize scores were <4. Borneol may improve the transcorneal penetration of both hydrophilic and lipophilic compounds without causing toxic reactions, especially hydrophilic ones. Furthermore, 0.2% borneol can enhance the permeation of hydrophilic compounds with molecular weight ≤4 kDa. Hence, borneol can be considered as a safe and effective penetration enhancer for ocular drug administration.

Diabetes in pregnancy may differentially affect neonatal outcomes for twins and singletons

Diabet. Med. 28, 1068–1073 (2011)

Abnormal fetal heart rate tracing patterns in patients with thick meconium staining of the amniotic fluid: association with perinatal outcomes

OBJECTIVE The objective of the study was to evaluate, in labors complicated by thick meconium-stained amniotic fluid, the association between specific fetal heart rate (FHR) patterns and adverse perinatal outcomes. STUDY DESIGN A retrospective cohort study of patients with FHR tracing data (n = 1638) from a previously reported randomized controlled trial of amnioinfusion for the prevention of meconium aspiration syndrome. RESULTS The presence of FHR tracing abnormalities was associated with an increased risk of perinatal mortality and/or neonatal morbidity (moderately abnormal: adjusted odds ratio [OR], 1.67; 95% confidence interval [CI], 1.18-2.37; markedly abnormal: adjusted OR, 2.97; 95% CI, 1.88-4.67). Specific abnormalities that were associated with the risk of perinatal mortality and/or neonatal morbidity included prolonged decelerations (OR, 1.22; 95% CI, 1.02-1.48), severe variable decelerations (OR, 1.08; 95% CI, 1.00-1.16), bradycardia (OR, 2.49; 95% CI, 1.02-6.11), and tachycardia (OR, 2.43; 95% CI, 1.49-3.94). CONCLUSION The presence of abnormal FHR tracing patterns in meconium-stained amniotic fluid patients is associated with an increased risk of adverse perinatal outcomes.