This is the protocol for a review and there is no abstract. The objectives are as follows:
The objectives of this review are:
(1) to determine the effectiveness and safety of any vitamin supplementation taken by women prior to conception, periconceptionally and in early pregnancy on the risk of:
(a) spontaneous miscarriage;
(b) maternal adverse outcomes;
(c) fetal and infant adverse outcomes.
(2) If vitamins are effective, to determine which of these agents are best and to compare vitamins with other interventions.