Relationship between vitamin D status in pregnancy and the risk for preeclampsia: A nested case-control study

Background & aims: Vitamin D is thought to be involved in the pathogenesis of preeclampsia. To evaluate the relationship between vitamin D insufficiency in the first trimester of pregnancy and preeclampsia. Methods: Nested case-control study (FEPED study) in type 3 obstetrical units. Pregnant women from 10 to 15 WA. For each patient with preeclampsia, 4 controls were selected from the cohort and matched by parity, skin color, maternal age, season and BMI. The main outcome measure was serum 25(OH)D status in the first trimester. Results: 83 cases of preeclampsia were matched with 319 controls. Mean 25(OH)D levels in the first trimester were 20.1 +/- 9.3 ng/mL in cases and 22.3 +/- 11.1 ng/mL in controls (p = 0.09). The risk for preeclampsia with 25(OH)D level >= 30 ng/mL in the first trimester was decreased, but did not achieve statistical significance (OR, 0.57; 95% CI, 0.30-1.01; p = 0.09). High 25(OH)D during the 3rd trimester was associated with a significantly decreased risk of preeclampsia (OR, 0.43; 95%CI, 0.23-0.80; p = 0.008). When women with 25(OH)D levels <30 ng/mL both in the first and 3rd trimesters ("low-low") were taken as references, OR for preeclampsia was 0.59 (95% CI, 0.31-1.14; p = 0.12) for "low-high" or "high-low" women and 0.34 (95% CI, 0.13-0.86; p = 0.02) for "high-high" women. Conclusions: No significant association between preeclampsia and vitamin D insufficiency in the first trimester was evidenced. However, women with vitamin D sufficiency during the 3rd trimester and both in the first and 3rd trimesters had a significantly lower risk of preeclampsia. (C) 2019 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.