Background: Maternal vitamin D status during fetal development may influence offspring growth and risk of obesity; however, evidence in humans is limited.
Objective: To investigate whether maternal circulating 25-hydroxyvitamin D3 (25(OH)D3) concentration in pregnancy is associated with offspring prenatal and postnatal growth and overweight.
Methods: Plasma 25(OH)D3 concentration was measured in pregnant women (median weeks of gestation 14.0, range 13.0-15.0) from the INMA (INfancia y Medio Ambiente) cohort (Spain, 2003-2008) (n = 2358). Offspring femur length (FL), biparietal diameter (BPD), abdominal circumference (AC) and estimated fetal weight (EFW) were evaluated at 12, 20 and 34 weeks of gestation by ultrasound examinations. Fetal overweight was defined either as AC or as EFW ⩾ 90th percentile. Child's anthropometry was recorded at ages 1 and 4 years. Rapid growth was defined as a weight gain z-score of >0.67 from birth to ages 6 months and 1 year. Age- and sex-specific z-scores for body mass index (BMI) were calculated at ages 1 and 4 years (World Health Organization referent); infant's overweight was defined as a BMI z-score ⩾ 85th percentile.
Results: We found no association of maternal 25(OH)D3 concentration with FL and a weak inverse association with BPD at 34 weeks. Maternal deficit of 25(OH)D3 (<20 ng ml(-1)) was associated with increased risk of fetal overweight defined as AC ⩾ 90th percentile (odds ratio (OR) = 1.50, 95% confidence interval (CI): 1.01-2.21; P = 0.041) or either as EFW ⩾ 90th percentile (OR = 1.47, 95% CI: 1.00-2.16; P = 0.046). No significant associations were found with rapid growth. Deficit of 25(OH)D3 in pregnancy was associated with an increased risk of overweight in offspring at age 1 year (OR = 1.42, 95% CI: 1.02-1.97; P = 0.039); however, the association was attenuated at age 4 years (OR = 1.19, 95% CI: 0.83-1.72; P = 0.341).
Conclusions: Vitamin D deficiency in pregnancy may increase the risk of prenatal and early postnatal overweight in offspring. Clinical trials are warranted to determine the role of vitamin D in the early origins of obesity.