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

Background. Birth spacing has been found to be independently associated with perinatal morbidity and mortality, with inappropriate birth spacing accounting for about 12-15% excess risk for maternal and infant death across the globe. There have been studies to identify the appropriate interval following preterm and term births as well as abortions, but little work has been done to identify the appropriate interval following a fetal loss. It can be extrapolated from previous studies that spacing a birth after a fetal loss would be essential in reducing adverse perinatal outcomes for subsequent pregnancies, but the question is what is the optimal interval? Currently, clinicians and health professionals in the United States are advocating pregnancy intervals of 18 to 24 months for women regardless of the birth outcome (excluding all abortions). However there is currently no research in support of this interval for women who experienced a fetal loss. Objective. To identify appropriate pregnancy intervals for women experiencing a fetal loss. Methods. A retrospective cohort was formed to evaluate pregnancy outcomes of women who had a reportable pregnancy immediately following a fetal death. Multilevel linear and logistic regression models assessed the association between pregnancy intervals and subsequent adverse pregnancy outcomes, controlling for gestational length of previous fetal death. An appropriate pregnancy interval is considered one that minimizes adverse maternal and perinatal health outcomes. Results. This study found that the interpregnancy interval corresponding to the lowest odds of an adverse outcome varied based on timing of previous fetal death. For early fetal death, the interpregnancy interval associated with the lowest odds of an adverse perinatal outcome was any interval longer than six months. For women who had a late fetal death, no interval was associated with a significantly lower odds ratio. Also, no interval was identified as the appropriate interval that offered protection against adverse maternal outcomes. Discussion. The results of this study can be used to influence clinician recommendations and public health interventions aimed at increasing pregnancy/birth intervals for the purposes of decreasing adverse perinatal outcomes.