First-trimester maternal serum 25-hydroxyvitamin D3 status and pregnancy outcome.

OBJECTIVE: To determine the pregnancy outcome as a function of the first-trimester serum 25-hydroxyvitamin D(3) [25(OH)D] status and to compare the 25(OH)D levels in the first and third trimesters. METHODS: Pregnant women (n=466) tested for serum 25(OH)D levels during the first trimester were followed up until the end of pregnancy, and the obstetric and neonatal outcomes were compared in reference to the baseline 25(OH)D status. The third-trimester 25(OH)D levels were additionally measured in a subset of women (n=148). RESULTS: The obstetric and neonatal outcomes did not vary as a function of the first-trimester 25(OH)D status. Neither did the 25(OH)D levels vary as a function of pregnancy outcomes. Overall, the 25(OH)D levels significantly decreased from the first to the third trimester. The first- and third-trimester 25(OH)D levels of samples initially taken during autumn/winter were significantly lower than those that were initially taken during spring/summer. Interestingly, the decrease in 25(OH)D levels during the third trimester was independent of the season of sampling. CONCLUSION: The pregnancy outcome was independent of the first-trimester 25(OH)D status. Overall, the 25(OH)D levels significantly decreased in the third trimester. More research in this area is warranted.

First trimester serum 25-hydroxyvitamin D status and factors related to lower levels in gravids living in the Spanish Mediterranean coast.

OBJECTIVE: To assess first trimester serum 25-hydroxyvitamin D [25(OH)D] status and factors related to deficient levels in pregnant Spanish women. METHODS: This cross-sectional study was carried out among 502 gravids (11 to 14 weeks) living in the Spanish Mediterranean sea coast (near Almería at latitude 36° N, longitude 2° W) to whom serum 25(OH)D levels were measured by electrochemiluminescence immunoassay. Logistic and multiple linear regression analysis were performed to assess the influence of ethnicity, immigration status, season of the year at blood sampling, body mass index (BMI), parity and smoking habit over 25(OH)D levels. RESULTS: The median (interquartile range, IQR) serum 25(OH)D levels for the entire sample was 27.4 ng/mL (IQR = 20.9-32.8). Only 35.9% of participants had adequate serum 25(OH)D levels (≥30 ng/mL) whereas in 41.4% and 22.7% these levels were found to be insufficient (20-29.9 ng/mL) and deficient (<20 ng/mL), respectively. Vitamin D status was found to be significantly lower in Arab women as compared to Caucasian women. 25(OH)D levels were positively correlated with gestational age at sampling and inversely with BMI values (univariate analysis). Logistic regression analysis determined that non-Caucasian ethnicity, season at sampling (autumn/winter), and nulliparity were factors related to deficient 25(OH)D levels. Multiple linear regression found a similar model yet also including maternal weight inversely correlating with 25(OH)D levels. CONCLUSION: Despite living in one of the sunniest, warmest, and driest climates of Europe, gravids displayed a high prevalence of first trimester insufficient/deficient serum 25(OH)D levels related to season at sampling, nulliparity, maternal weight, and non-Caucasian ethnicity.