Observational Study of Third-Trimester Vitamin D3 Supplementation and Implications for Mothers and Neonates at Term.

Abstract

To determine 25-hydroxyvitamin D (25OHD) levels in pregnant women at 28weeks and supplement based on these levels and check maternal and neonatal levels after delivery at term. This is a prospective observational study wherein pregnant women aged 18-35years received cholecalciferol from 28weeks till delivery at term. Women with 25OHDlevels ≥75nmol/L received 12.5μg/day, those with levels 50-74.9nmol/L received 100μg/day and those with levels ≤49.9nmol/L received 1500μg/week. Of 555, 532 women (95.8%) completed the study. Of 532, 77 (14.5%) women had 25OHD≥75nmol/L at 28weeks; 34/77 (44.15%) became deficient at term, and the mean 25OHD reduced from 99±29.9 to 77±30.4nmol/L (p<0.0001). One hundred and seventy-one women had 25OHD 50-74.9nmol/L at 28weeks; in 99 (57.89%), levels normalised at term, and mean 25OHD increased from 60.5±7.5 to 78.2±21.9nmol/L (p<0.0001). Two hundred and nineteen women had 25OHD 25-49.9nmol/L at 28weeks; in 135 (61.64%), levels normalised at term, and mean 25OHD increased from 36.6±7.5 to 83.3±32.7nmol/L (p<0.0001). Sixty-five women had 25OHD<25nmol/L at 28weeks; In 39 (60.94%), levels normalised at term, and the mean 25OHD increased from 17.9±5 to 80.6±34.1nmol/L (p<0.0001). Seven neonates (1.3%) had cord blood ionised calcium values<1mmol/L, and all these had 25OHD<50nmol/L (mean 22.2±2.5nmol/L). Standard 12.5μg/day supplementation in women with normal 25OHD levels at 28weeks leads to deficiency in 44% women by term. Cholecalciferol in doses of 100μg/day and 1500μg/week leads to a significant increase in 25OHD levels in vitamin D-deficient pregnant women though nearly 40% may still have deficient levels at term along with their newborns. Only 1.3% of newborns had hypocalcaemia.