Table 11. The effect of vitamin D supplementation in gestation on offspring birth length – Intervention studies.

First Author, year	Risk of bias	Setting	Randomisation	Adjustments/ confounders accounted for	Number of weeks gestation when 25(OH)D was measured	Mean (SD) or median (IQR) 25(OH)D concentration (nmol/1)	Mean (SD) or Mean (SE)* birth length (cm) in un-supplemented group	Mean (SD) or Mean (SE)* birth length (cm) in supplemented group	Conclusion
Brooke, 1980 4	−2 (high)	London, UK, n=126 women(all Asian)	Double-blinded Randomised to either placebo (n=67) or 1000 IU/day of vitamin D2 in last trimester (n=59)	Nil, but groups of similar age, height, parity, offspring sex, length of gestation	28-32 weeks and at birth	At allocation 25(OH)D = 20.1 (1.9) At term, Controls 25(OH)D= 16.2 (2.7) At term, supplemented group 25(OH)D = 168.0 (12.5)	49.5 (0.4)*	49.7 (0.3)*	No significant difference in birth length between groups p>0.05
Marya, 1988 6	−2 (high)	Rohtak, India	Randomised to either no supplement (n=100) or oral 600,000 IU vitamin D3; 2 doses in 7th and 8th months gestation (n=100)	Nil, but groups had similar maternal age, maternal height, maternal height, parity, haemoglobin, calcium intake and vitamin D intake	Not measured	Not measured directly, but mean daily vitamin D intake given as follows Un-supplemented = 35.71 (6.17) IU/day Supplemented group = 35.01 (7.13) IU/day	48.45 (2.04)	50.06 (1.79)	Birth length significantly higher in the supplemented group p<0.001