Abstract
BACKGROUND: Vitamin D may influence circulating levels of sex steroid hormones in women during reproductive life, but associations in pregnant women have not been explored. METHODS: Correlation and linear regression models were used to assess the association between sex steroids, (estradiol, progesterone, 17-hydroxyprogesterone, testosterone, and androstenedione), IGF-1, and serum 25-hydroxyvitamin D (25-OHD) concentrations during the first trimester of pregnancy in 106 cancer-free women from the Finnish Maternity Cohort. RESULTS: There was no significant association of serum 25-OHD with any of the hormones measured. One-unit increase in serum 25-OHD concentration was associated with a non-significant 6% increase in estradiol concentrations. Multiparous women had higher levels of vitamin D (40.4 vs. 32.9 nmol/L, p-value = 0.01) than primiparous women. CONCLUSION: Our study does not support an association between maternal serum 25-OHD levels and sex steroids or IGF-I concentrations during the first trimester of pregnancy.