Effects of interpregnancy intervals immediately following a fetal death on perinatal health

Inappropriate birth spacing accounts for about 12-15% excess risk of infant death across the globe. US health practitioners are advocating for birth intervals of 18 to 24 months for women regardless of the birth outcome. However there is no research in support of this interval for women who experienced fetal loss. A retrospective cohort was formed to evaluate interpregnancy intervals immediately following a fetal death and resulted in a healthy subsequent pregnancy outcome. Records were reviewed for 1530 women with a reportable pregnancy immediately following a fetal death from 1990-2006. Multivariate logistic regression models assessed the association between pregnancy intervals and subsequent adverse pregnancy outcomes, controlling for maternal risk factors and other confounders. An appropriate interpregnancy interval was considered one that minimizes adverse perinatal health outcomes. The interpregnancy interval corresponding to the lowest odds of an adverse outcome varied in our study based on timing of previous fetal death. For early fetal death (<28 weeks), the interpregnancy interval associated with the lowest odds of an adverse perinatal outcome was any interval longer than six months with an OR of 0.35(0.18, 0.71). For women who experienced a late fetal death (>28 weeks), the interval associated with the lowest odds of an adverse birth outcome was 6-24 months, OR=0.51(0.25, 1.0) with the odds of an adverse pregnancy outcome increasing after 24 months. These analyses suggest that different birth spacing recommendations should be made for women who experience a fetal death and based on the timing of the previous fetal death.