Maternal and umbilical cord 25(OH)D levels at delivery and
identification of factors affecting the correlation: a prospective
observational study from a northern Emirate.
Abstract
25-hydroxyvitamin-D (25(OH)D) level in the fetus entirely depends on the
transport over placenta which is assumed to be obstructed with maternal
levels <25nmol/L. Design Observational study. Setting
Prospectively enrolling from September to December 2021 in a tertiary
governmental hospital in a northern Emirate. Population Admission for
spontaneous and elective labor. Methods 25(OH)D was analyzed in maternal
serum at admission, respectively, in cord blood after delivery. Main
outcome measures Factors affecting maternal and fetal 25(OH)D levels and
the correlation between the two at delivery. Results 303 women were
enrolled and 237 had complete maternal/umbilical cord blood samples. 138
(47.7%) of women were diagnosed with deficiency
(25(OH)D<50nmol/L), whereas only 34 fetuses (13.8%) were
deficient (25(OH)D<30nmol/L). The mean difference between
maternal and cord blood 25(OH)D was negative in 91% of cases
(-16.27nmol/L, SD=13.36). The correlation between maternal/umbilical
cord levels was excellent (r = 0,906, p<0,000). After dividing
into subgroups of maternal 25(OH)D levels, BMI, diabetes yes/no and
delivery-mode the correlation was consistent, although the correlation
coefficients in the subgroups of maternal 25(OH)D levels were lowered
for all groups. Of factors studied, only the supplementation dose
affected the maternal 25(OH)D level. 25(OH)D <50nmol/L was not
associated to an increased risk for diabetes, preterm labor,
preterm-rupture-of-membranes or low Apgar-score. Conclusion We found a
higher 25(OH)D level in cord blood with consistent correlation to
maternal levels. Of the studied factors only supplementation dose had
significant impact on the maternal level. 25(OH)D <50nmol/l
were not associated to increased risk for preterm-labor,
preterm-rupture-of-membranes, diabetes or low AS.