Time to conception after miscarriage: How long to wait?
EVIDENCE-BASED ANSWER:
An interpregnancy interval (IPI) of < 6 months following miscarriage is associated with an increased live birth rate in subsequent pregnancy, lower risks of preterm birth and subsequent miscarriage, and no difference in rates of stillbirth, pre-eclampsia, and low birth weight infants (strength of recommendation [SOR]: A, well-done meta-analysis). (IPI is defined as the time between the end of one pregnancy and the last menstrual period of a subsequent one.)
A very short IPI (< 3 months), when compared with an IPI of 6 to 18 months, is associated with the lowest rate of subsequent miscarriage (SOR: B, cohort study). However, for women who experience a pregnancy loss at 14 to 19 weeks’ gestation, an IPI < 3 months is associated with an increased risk of miscarriage or birth before 24 weeks’ gestation (SOR: B, cohort study).
Women with a short IPI following miscarriage may be at increased risk for anxiety and depression in the first trimester of the subsequent pregnancy (SOR: B, cohort study).
RECOMMENDATIONS
The American College of Obstetricians and Gynecologists’ Practice Bulletin on Early Pregnancy Loss states that no quality data exist to support delaying conception after early pregnancy loss (defined as loss of an intrauterine pregnancy in the first trimester) to prevent subsequent pregnancy loss or other pregnancy complications.11
WHO recommends a minimum IPI of at least 6 months after a spontaneous or elective abortion. This recommendation is based on a single multi-center cohort study in Latin America that included women with both spontaneous and induced abortions.8
Editor’s takeaway
High-quality evidence now shows that shorter IPIs after first-trimester miscarriages result in safe subsequent pregnancies. However, some concern remains about second-trimester miscarriages and maternal mental health following a shorter IPI, based on lower-quality evidence.
