Background: This study was aimed to investigate the relationship between 25-hydroxy vitamin D (25(OH)D) level and the occurrence of pre-eclampsia (PE) and also the risk factors of developing early and late onset PE.
Methods: A total of 370 pregnant women were included between January 2015 and December 2016 at our hospital. PE was defined as the presence of maternal blood pressure > 140/90 mmHg and 24-hour proteinuria levels > 300 mg or 2 + in a random sample of urine after the 20th week of pregnancy. Controls were pregnant women without hypertension and proteinuria. Assessment of 25(OH)D was performed at 16 - 20 weeks of gestation. Univariate and multivariate analyses were used to evaluate the association of vitamin D with PE.
Results: There were 201 patients with PE while 169 pregnant women were controls. Patients with PE had older maternal age (p < 0.001), earlier gestation age (p < 0.001), and higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) (p < 0.001). The level of 25(OH)D in the PE group (17.26 ± 13.95 µg/L) was significantly lower than that in controls (22.15 ± 12.65 µg/L, p = 0.019). Moreover, the proportion of 25(OH)D deficiency in patients with PE was significantly higher than that of controls (27.6% vs. 0.9%, p < 0.001). Older age, high SBP, and low level of 25(OH)D were independent risk factors of both early and late onset PE during pregnancy.
Conclusions: Low 25(OH)D level was more likely presented in PE patients and was an independent risk factor of both early and late onset PE.