(459) Risk of Recurrent Stillbirth in a Subsequent Pregnancy

This study aimed to quantify the risk of recurrent stillbirth following an initial stillbirth. A second aim was to evaluate the contribution of placental insufficiency to the recurrence risk.

Study Design:

This was a retrospective cohort study of 77,689 women with two consecutive singleton deliveries at a single academic institution between 2000-2023. Stillbirth was defined as a fetal demise occurring at ≥ 20 weeks of gestation or with a birth weight ≥ 500g. Women who experienced a stillbirth in their first pregnancy were compared to those who had a live birth, to assess whether stillbirth increased the risk of recurrent fetal demise in the subsequent pregnancy. A multidisciplinary stillbirth review committee routinely studied the etiology of all stillborn infants. Identification of stillbirth secondary to placental insufficiency was based on integrated evaluation of placental pathology, autopsy findings, and genetic testing. A subgroup analysis examined those with prior placental insufficiency. Statistical analysis was performed including adjustment for maternal age as continuous variable with P< 0.05 considered significant.

Results:

A prior stillbirth was associated with a significantly increased risk of stillbirth in a subsequent pregnancy (RR 2.44, 95% CI 1.10–5.45, p=0.025). This relationship remained statistically significant after adjustment (aRR 2.33, 95% CI 1.05–5.20, p=0.04). Among patients whose initial stillbirth was due to placental insufficiency, the risk of recurrence was significantly higher (RR 6.00, 95% CI 1.52–23.59, p=< 0.01).

Conclusion:

Women who experience a stillbirth in their first pregnancy have a significantly increased risk of stillbirth in their next pregnancy, with a markedly higher risk observed when the initial loss is due to placental insufficiency. These findings underscore the importance of determining the cause of prior stillbirth and surveillance in subsequent pregnancies.