Table 20. The effect of vitamin D supplementation in gestation on risk of offspring being born small for gestational age in the offspring – 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/l)			Percentage of infants SGA* in un-supplemented group	Percentage of infants SGA* 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 25OHD3 = 168.0 (12.5)			28.6% (19 out of 67)	15.3% (9 out of 59)	No significant difference in risk of SGA between groups p>0.05; X2 = 3.1
Yu, 2009 96	5 (low)	London, UK n=119 women	3 arms Randomised to either no supplement (n=59) or oral vitamin D2 800 IU/day vitamin from 27 weeks onwards (n=60), or a single 200,000 IU D2l at 27 weeks gestation (n=60) Each group contained equal numbers of 4 ethnic groups (Caucasian, Black, Asian, Middle Eastern)	Nil No significant difference in baseline characteristics across the 3 groups	Measured at 26-27 weeks and again at delivery		27 wks	Delivery	17%	15% in daily dose group 13% in stat dose group	No significant difference in rate of SGA across the 3 groups p=0.7
						No sup	25 (21-38	27 (27-39)
						Daily sup	26 (20-37)	42 (31-76)
						Single sup	26 (30-46)	34 (30-46)

^*SGA defined as infants born <10^th percentile of birth weight