First trimester serum levels of 25-hydroxyvitamin D, free β-human chorionic gonadotropin, and pregnancy-associated plasma protein A in Spanish women

Background. Vitamin D has been implicated in embryo/placental development and growth; however information in this regard is limited or unavailable. Objective. To assess 25-hydroxyvitamin D (25(OH)D), free β-human chorionic gonadotropin (β-hCG) and pregnancy associated plasma protein A (PAPP-A) status during pregnancy. Methods. Serum 25(OH)D, β-hCG, and PAPP-A levels were measured in the first trimester of otherwise healthy Spanish pregnant women (n = 488). Rho Spearman coefficients were calculated to determine correlations between analytes. Results. Median serum 25(OH)D levels for the entire sample was 27.4ng/ml (interquartile range = 12.1). 25(OH)D levels were insufficient (2029.99ng/ml) and deficient (<20ng/ml) in 40.6% and 23.2%, respectively, in relation to ethnics, body mass index values, tobacco use, and season/gestational age at blood sampling. β-hCG and PAPP-A levels significantly correlated (r ² = 0.47) yet neither of them with 25(OH)D levels. Despite this, the three analytes significantly correlated with gestational age at sampling. Conclusion. First trimester 25(OH)D, β-hCG, and PAPP-A levels increase with gestational age; however, placental peptides do not correlate with vitamin D levels, suggesting a non-placental 25(OH)D production. More research is required in this regard.