Serum level of vitamin D in women with idiopathic preterm labor and women with term labor referred to Bentolhoda hospital in Bojnourd, 2020

The association of maternal vitamin D status with preterm labor has been considered in the recent decade, although reported findings have been inconsistent. This study was performed aimed to compare serum 25-hydroxy vitamin D levels between women with idiopathic preterm labor and women with term labor.

This case-control study was performed in 2020 on 60 women aged 18-35 years who had referred to Bentolhoda Hospital in Bojnourd for delivery. Serum levels of 25-hydroxyvitamin D were determined in 30 women with idiopathic preterm delivery with gestational age of 28 to 37 weeks (case group) and 30 women with term delivery (control group) by sandwich ELISA. Patients' information including demographic information, clinical status and pregnancy history were collected through a questionnaire. Data were analyzed by SPSS 16 software (version 16) and Chi-square and Pearson correlation coefficient test. P<0.05 was considered statistically significant.

About fifty-six (93.4%) of the participating mothers had some degree of vitamin D deficiency. Previous history of abortion, still birth and previous preterm labor were not associated with preterm labor, but primigravida increase the risk of preterm labor up to 8 times. The mean 25 (OH) D in women with preterm labor was higher than control group (19.8±8.9 vs. 14.52 ± 5.4 ng/ml, P = 0.007).

Although serum vitamin D level in mothers with preterm labor was significantly higher than those with term labor, but due to the limitations of this study, we cannot rule out the possibility of vitamin D deficiency as a risk factor for preterm labor.