A recent study published by the journal Placenta found that preeclampsia was linked with increased breakdown, reduced activation and impaired placental uptake of vitamin D.
Preeclampsia is a rapidly progressing condition that typically occurs after 20 weeks gestation. Those with preeclampsia experience high blood pressure, swelling in the hands and feet and protein in the urine.
Due to its rapid progression, severe preeclampsia is life threatening for both the mother and her unborn baby. Approximately 76,000 mothers and 500,000 infants die each year as a result of complications from preeclampsia and other hypertensive disorders during pregnancy.
Vitamin D plays an important role in maternal health. In fact, low vitamin D status has been linked with several adverse maternal health outcomes, including preeclampsia, preterm birth, low birth weight and autism. Furthermore, healthy vitamin D status [25(OH)D > 40 ng/ml] has been shown to reduce the risk of developing preeclampsia.
Although studies continue to validate the relationship between serum 25(OH)D status and preeclampsia risk, there is a lack of research evaluating other key vitamin D metabolites. Therefore, researchers recently evaluated whether vitamin D metabolite concentrations varied between normal and preeclamptic pregnancies.
A total of 25 women in their 1st trimester with a normal pregnancy, 21 women with a normal pregnancy in their 3rd trimester, 22 women with preeclampsia and 20 non-pregnant controls were included in the study. The researchers measured the vitamin D metabolites via serum analysis, placental and decidual tissue biopsy. Decidual tissue refers to the uterine lining during pregnancy.
Here is what the researchers found:
- Serum 25(OH)D did not differ significantly between the 4 groups.
- Active vitamin D was significantly lower among the non-pregnant women than both healthy and preeclamptic pregnant women (p < 0.0001).
- Active vitamin D levels were over two-fold higher among the healthy pregnant women in the 3rd trimester compared to the first trimester (p < 0.0001).
- Those with preeclampsia had significantly lower active vitamin D levels than the healthy pregnant women in the 3rd trimester (p < 0.01).
- Serum 24,25(OH)2D3, the first breakdown product of both 25(OH)D and 1a,25(OH)2D, was highest among pre-eclamptic women, followed by healthy women in their 3rd trimester, those in their first trimester and non-pregnant women (p < 0.05).
- Among healthy women in the 3rd trimester, total, free and bioavailable maternal 25(OH)D were associated with placental 25(OH)D; however, this was not the case for those with preeclampsia.
The researchers concluded,
“These data indicate that preeclampsia is associated with decreased activation, increased catabolism, and impaired placental uptake of 25(OH)D3.”
The researchers highlighted the clinical implications of these findings. In this study, 25(OH)D status of healthy pregnancies is tightly related to placental vitamin D status, indicating vitamin D supplementation is beneficial during pregnancy. However, those with preeclampsia experience impaired vitamin D metabolism, potentially impacting the health of their offspring.
The researchers stated,
“Validation of these findings in a high-powered, matched cohort study including pregnant women with [preeclampsia] versus normotensive pregnant and non-pregnant controls is required to inform any future vitamin D supplementation trial targeting correction of the vitamin D metabolome.”
Sturges, M. & Cannell, JJ. Preeclampsia associated with impaired placental vitamin D metabolism. The Vitamin D Council Blog & Newsletter, 2/2017.