ABSTRACT
Objective 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.
Keywords: Vitamin D, 25(OH)D, pregnancy, fetal cord blood,
diabetes, obesity.
Tweetable abstract: 25(OH)D level in cord blood is higher than
in maternal blood with a strong correlation not influenced by maternal
levels, delivery mode, BMI or diabetes.
Funding: Sheikh Khalifa Medical City, Ajman