Maternal Vitamin D Status and the Risk of Mild and Severe Preeclampsia

Abstract

Background We sought to determine the association between maternal vitamin D status at ≤26 weeks gestation and the risk of preeclampsia separately by clinical subtype. Methods We conducted a case-cohort study among women enrolled at 12 U.S. sites from 1959 to 1966 in the Collaborative Perinatal Project. In 717 women who later developed preeclampsia (560 mild and 157 severe cases) and in 2986 mothers without preeclampsia, we measured serum 25-hydroxyvitamin D at ≤26 weeks gestation (median 20.9 weeks) over 40 years later using liquid-chromatography-tandem mass spectrometry. Results Half of women in the subcohort had 25(OH)D <50 nmol/L. Maternal 25(OH)D 50–<75 nmol/L was associated with a reduction in the absolute and relative risk of preeclampsia and mild preeclampsia compared with 25(OH)D <30 nmol/L, but the effects were no longer present after adjustment for confounders including race, prepregnancy body mass index, and parity. For severe preeclampsia, 25(OH)D ≥50 nmol/L was associated with a reduction of 3 cases per 1,000 pregnancies (adjusted RD −.003, 95% CI: −.005, .0002) and a 40% reduction in risk (adjusted RR .65, 95% CI .43, .98) compared with 25(OH)D <50 nmol/L. The conclusions were the same after restricting to women with 25(OH)D measured at <22 weeks gestation and after formal sensitivity analyses for unmeasured confounding. Conclusions Maternal vitamin D deficiency may be a risk factor for severe preeclampsia, but it is not associated with preeclampsia overall or its mild subtypes. Contemporary cohorts with large numbers of severe preeclampsia cases are needed to confirm or refute these findings.

Effect of vitamin D supplementation during pregnancy on maternal and neonatal outcomes: a systematic review and meta-analysis of randomized controlled trials

“…Controversy remains regarding the clinical and epidemiologic evidence on the relationship between low maternal vitamin D levels and the risk of preeclampsia (39,40). In the current meta-analysis, 3 RCTs assessed vitamin D supplementation and preeclampsia risk and did not find any significant association between them.…”

“…Other confounding factors not assessed in available RCTs include diet, vitamin D content, seasonality, body weight gain during pregnancy, ethnicity, and skin characteristics (3,4,6,39,53,55). Birth spacing was not reported in the RCTs, and therefore we could not control for this factor.…”

A study of vitamin D levels and associated deficiency in pregnancy and its effect on maternal and fetal outcome

“…Younger women below 30 years old (43.2%, P = 0.032), housewives (65.3%, P = 0.008), and those on low monthly household incomes (QR5,000-9,999) (49.2%, P = 0.03) were significantly more likely to have lower vitamin D compared with those who had sufficient vitamin D levels in Doha study. 1,6 In study by Bener A Exposure to sunlight (63.4%, P = 0.05), daily physical activity (64.4%, P = 0.05), and vitamin D supplement intake (89.7%, P < 0.001) were significantly lower in deficient pregnant women. 1,6 It was observed in our study that more exposure to sun (38.1%) and supplement of vitamin D intake (38.2%) have less deficiency than those who are more exposure to sun and took supplement.…”

“…1,6 In study by Bener A Exposure to sunlight (63.4%, P = 0.05), daily physical activity (64.4%, P = 0.05), and vitamin D supplement intake (89.7%, P < 0.001) were significantly lower in deficient pregnant women. 1,6 It was observed in our study that more exposure to sun (38.1%) and supplement of vitamin D intake (38.2%) have less deficiency than those who are more exposure to sun and took supplement. The risk of vitamin D deficiency was higher in housewives and those with low monthly household income.…”

“…Lack of vitamin D has been linked to diabetes and increased rates of cesarean section births and pre eclampsia. [1][2][3] In children, the deficiency can cause rickets and soft bone disease.…”