The effects of a postmiscarriage menstrual period prior to reconceiving

BACKGROUND: The optimal interpregnancy interval after a single pregnancy loss is controversial. It is common obstetrical practice to recommend that women who have had a miscarriage in the first trimester of pregnancy should wait for 1 or more menstrual cycles before attempting to conceive again.OBJECTIVE: This study aimed to assess whether conception before the first menstrual period after a spontaneous pregnancy loss is associated with a risk of repeat miscarriage or adverse perinatal outcomes.STUDY DESIGN: This retrospective cohort study included 107 women who had a spontaneous miscarriage in the first trimester of pregnancy followed by a subsequent pregnancy with an interpregnancy interval of <12 weeks. All miscarriages had ended in either spontaneous expulsion of the products of conception or medical or surgical evacuation of the uterus. The perinatal outcome measures of 57 women who conceived after the first menstrual period following a spontaneous miscarriage were compared with perinatal outcome measures of 50 women who conceived before the first menstrual period following a spontaneous miscarriage. The primary outcome was rate of pregnancy loss, and the secondary outcomes were gestational age at delivery and birthweight.RESULTS: The rate of recurrent miscarriage was 10.4% for women who conceived before the first menstrual period following a spontaneous miscarriage and 15.8% for those who conceived after (P=.604). There were no differences in the gestational age at delivery (38.9 vs 38.7 weeks; P=.66) or the birthweight (3347 +/- 1173 vs 3412 +/- 1156 g; P=.5) between the 2 groups. Other outcomes, such as mode of delivery and 5-minute Apgar score, were also similar for both groups. A multiple logistic regression analysis confirmed that conception before the first menstrual period following a spontaneous miscarriage was not associated with a higher incidence of subsequent miscarriage (odds ratio, 1.74; P=.46) or any other untoward outcome.CONCLUSION: Conception shortly after a spontaneous miscarriage without waiting for at least the first postmiscarriage menstrual period is not associated with adverse maternal or neonatal outcomes compared with those of women with similar interpregnancy intervals who conceived after their next menstrual period.