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

Abstract

Objective Whether vitamin D deficiency in pregnancy is a cause of pre-eclampsia remains controversial. Most previous studies to date have assessed exposure at only one time-point in pregnancy.We assessed longitudinal vitamin D status during pregnancy and the risk of pre-eclampsia.Design Prospective cohort study.Setting Seventeen urban obstetric hospitals, Canada.Population Pregnant women who were participants in a trial of vitamin C and E supplementation for the prevention of preeclampsia. Canadian participants who consented to participate in a biobank with plasma specimens available at the baseline visit were included (n = 697).Methods Maternal plasma 25-hydroxyvitamin D (25(OH)D) concentrations were measured at 12-18 and 24-26 weeks of gestation using chemiluminescence immunoassay.Main outcome measures Pre-eclampsia.Results Of the women, 39% were vitamin D deficient (25(OH)D <50 nmol/l). A strong positive correlation was observed in maternal 25(OH)D concentrations between the two gestational age windows (r = 0.69, P < 0.0001). Mean maternal 25(OH)D concentrations at 24-26 weeks of gestation were significantly lower in women who subsequently developed pre-eclampsia compared with those who did not (mean ± SD: 48.9 ± 16.8 versus 57.0 ± 19.1 nmol/l, P = 0.03). Women with 25(OH)D < 50 nmol/l at 24-26 weeks gestation experienced an increased risk of pre-eclampsia (adjusted odds ratio 3.24, 95% confidence interval 1.37-7.69), whereas the association was not statistically significant for maternal 25(OH)D level at 12-18 weeks of gestation.Conclusions Lower maternal 25(OH)D levels at late mid-trimester were associated with an increased risk of pre-eclampsia.

Incidence of maternal vitamin D deficiency in a region of Ankara, Turkey: a preliminary study

“…Congenital rickets and neonatal hypocalcemic seizures are the early neonatal findings of maternal vitamin D deficiency (1,2). In mothers with low vitamin D levels, in addition to the classical findings of vitamin D deficiency, the risks of preeclampsia, gestational diabetes, prematurity, and infants small for gestational age have been found to be high (3)(4)(5). Besides the early neonatal effects of maternal vitamin D deficiency, long-term effects have also been reported.…”

F2-isoprostanes are correlated with trans fatty acids in the plasma of pregnant women

“…This comprised a subset of the 665 possible uncomplicated pregnancies recruited in 17 Canadian centers over a 26-month period. The patients' data for the Maternal and Infant Research on Oxidative Stress (MIROS cohort) have been published previously [46]. Plasma samples from twenty-one normotensive (≤ 140/90 mm Hg) pregnant women were collected at the Centre Mère-Enfant du Centre Hospitalier Universitaire de Québec (CHUL cohort) within a oneyear period.…”

Plasma F2-isoprostane class VI isomers at 12–18 weeks of pregnancy are associated with later occurrence of preeclampsia

“…The clinical characteristics of the pregnant's cohort used in this study was published in details previously [14]. Briefly, the PE group was constituted of 33 pregnancies in which, 21 pregnancies were obtained from a predetermined high-risk group according to one or many of the following risk factors; chronic hypertension, prepregnancy diabetes, multiple pregnancy, or a history of PE.…”

“…Patients' clinical data and biological samples were obtained from a biobank, the Maternal and Infant Research on Oxidative Stress (MIROS cohort) described previously [14]. Plasma from sixty women with uncomplicated pregnancies were recruited prospectively early between the 12 th to the 18 th weeks of pregnancy from a subset of the 665 possible uncomplicated pregnancies recruited by the MIROS study group in 17 Canadian centers over a 26-month period.…”

“…Venous blood was collected into EDTA tubes and plasma samples were immediately separated by centrifugation at 500 × g for 10 minutes at 4°C. Centrifuged plasma samples were rapidly frozen and stored at −80°C [14]. Butylated hydroxytoluene (BHT) was added (0.1%) before aliquoting [10].…”