Background: Vitamin D deficiency can occur in people whose diet is relatively low in the vitamin and those who are not exposed to much sunlight.
Objectives: The objective of this review was to assess the effects of vitamin D supplementation on pregnancy outcome.
Search strategy: We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register (October 1998).
Selection criteria: Acceptably controlled trials of vitamin D supplementation during pregnancy.
Data collection and analysis: One reviewer assessed trial quality and extracted data.
Main results: Two trials involving 232 women were included. In one trial the mothers had higher mean daily weight gain and lower number of low birthweight infants. In the other trial the supplemented group had lower birthweights.
Reviewer's conclusions: There is not enough evidence to evaluate the effects of vitamin D supplementation during pregnancy.