BACKGROUND: Insufficient supply of vitamin D during early development may negatively affect offspring growth.
METHODS: We examined the association between umbilical cord (UC) serum 25-hydroxyvitamin D (25(OH)D) concentrations and infant size in a study of two Faroese birth cohorts of 1038 singleton infants. In the third trimester, the pregnant women completed questionnaires, and clinical examination included birthweight, head circumference, and infant length at age 14 days.
RESULTS: Fifty-three percent of the newborn population had UC 25(OH)D < 25 nmol/L as determined by LC-MS/MS. Using multiple linear regression models with adjustment for pre-pregnancy BMI, sex, parity, gestational age, or infant age at examination, season of birth, smoking, gestational diabetes, examiner, and cohort identity, we found no relationship between birthweight or head circumference and UC 25(OH)D. However, infants with vitamin D status <12 nmol/L had a 0.49 (95% confidence interval 0.05, 0.93) cm lower length than infants with vitamin D status >50 nmol/L in models further adjusted for birthweight.
CONCLUSION: Our data suggest that umbilical cord serum 25(OH)D concentrations are positively associated with infant length but not with birthweight and head circumference. Although the paediatric relevance of the observed association is unclear, the possible long-term consequences of late-pregnancy hypovitaminosis D deserve attention.