Relevance of the miscarriage-new pregnancy interval.

There is a wide divergence of opinion concerning the interval a woman should wait after a miscarriage before attempting a new pregnancy ("pregnancy interval"). Many authors recommend waiting 3-4 months in order to reduce the risk of another miscarriage [3, 6, 17, 21]. This retrospective study investigated whether a longer pregnancy interval lowers the risk of repeat miscarriage (R-risk) and/or prematurity. The association between parity and R-risk was also analyzed. Results showed that there are no proven reasons to recommend a waiting period between a miscarriage and a subsequent pregnancy, because the R-risk was around 20% irrespective of interval duration. Prematurity too is not influenced by a waiting period after miscarriage. There was, however, an association between parity and R-risk and risk of prematurity: nulliparae were more likely to have a repeat miscarriage (p < 0.05) or a preterm delivery in the next pregnancy (p < 0.05) than women who had already given birth to a child.