Plain language summary
The role of vitamin D has been recognised during pregnancy, such as for calcium absorption and regulation of placental calcium transport. The aim of this study was to assess the efficacy and the pregnancy outcomes of different doses of vitamin D supplementation in pregnant women (Pakistan), where vitamin D deficiency is very high. This study is a double-blind randomised controlled trial that enrolled a total of 350 women. Study participants were randomly allocated into three groups of vitamin D3 supplementation: 4000IU/day (group A), 2000IU/day (group B) and 400IU/day (group C - control). Results indicate that vitamin D supplementation of 4000IU/day was more effective in reducing vitamin D deficiency among pregnant women and improving serum 25 Hydroxyvitamin D levels in mothers and their neonates compared with 2000IU/day and 400IU/day. Moreover, all formulations of supplementation are safe as no adverse events were reported. Authors conclude that further studies with new-borns of mothers enrolled in supplementation trials are needed particularly by focusing on the long-term outcomes and benefits of Vitamin D supplementation.
Abstract
BACKGROUND Vitamin D deficiency during pregnancy is a public health problem in Pakistan and is prevalent among most women of reproductive age in the country. Vitamin D supplementation during pregnancy is suggested to prevent adverse pregnancy outcomes and vitamin D deficiency in both the mother and her newborn. METHODS We conducted a double-blinded, randomised controlled trial in Karachi, Pakistan to evaluate the effect of different doses of vitamin D supplementation during pregnancy on biochemical markers (serum 25(OH)D, calcium, phosphorus and alkaline phosphatase) in women and neonates, and on pregnancy and birth outcomes (gestational diabetes, pre-eclampsia, low birth weight, preterm births and stillbirths). RESULTS Pregnant women (N=350) in their first trimester were recruited and randomised to three treatment groups of vitamin D supplementation: 4000 IU/day (group A, n=120), 2000 IU/day (group B, n=115) or 400 IU/day (group C, n=115). Women and their newborn in group A had the lowest vitamin D deficiency at endline (endline: 75.9%; neonatal: 64.9%), followed by group B (endline: 84.9%; neonatal: 73.7%) and then the control group (endline: 90.2%; neonatal: 91.8%). Vitamin D deficiency was significantly lower in group A than in group C (p=0.006) among women at endline and lower in both groups A and B than in the control group (p=0.001) in neonates. Within groups, serum 25(OH)D was significantly higher between baseline and endline in group A and between maternal baseline and neonatal levels in groups A and B. Participant serum 25(OH)D levels at the end of the trial were positively correlated with those in intervention group A (4000 IU/day) (β=4.16, 95% CI 1.6 to 6.7, p=0.002), with food group consumption (β=0.95, 95% CI 0.01 to 1.89, p=0.047) and with baseline levels of serum 25(OH)D (β=0.43, 95% CI 0.29 to 0.58, p<0.0001). CONCLUSION The evidence provided in our study indicates that vitamin D supplementation of 4000 IU/day was more effective in reducing vitamin D deficiency among pregnant women and in improving serum 25(OH)D levels in mothers and their neonates compared with 2000 IU/day and 400 IU/day. Trial registration number NCT02215213.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
