Associations between maternal injury and adverse perinatal outcomes: evidence from a retrospective cohort study

Maternal injury affects 6% to 8% of pregnancies and is associated with perinatal complications. Some outcomes remain understudied, with limited evidence on variation of associations by injury characteristics.

To estimate associations between maternal injury and adverse perinatal outcomes.

We conducted a retrospective cohort study using electronic health record data at the Atrium Health Wake Forest Baptist health system (2018-2024 births). We identified maternal injury using validated ICD-10-CM diagnostic codes and stratified injury by mechanism (transport accident, fall, other unintentional, intentional), trimester, location (abdominal, nonabdominal), and severity (severe: Abbreviated Injury Scale≥2). Time-varying Cox proportional hazards models estimated associations between injury and severe maternal morbidity (SMM), stillbirth, cesarean delivery, and placental abruption, identified using ICD-10-CM codes.

Among 58,897 deliveries, 1801 (3.1%) experienced maternal injury. SMM, stillbirth, cesarean delivery, and placental abruption occurred in 4.6%, 0.2%, 35%, and 0.3% of deliveries, respectively. Injury was associated with increased risk of cesarean delivery (hazard ratio [HR] 1.09, 95% CI 1.01-1.18), especially from falls (HR 1.21, CI 1.04-1.41), and placental abruption (HR 2.74, CI 1.50-4.99), especially from transport accidents (HR 3.33, CI 1.46-7.61). Second trimester, severe, and abdominal injury increased risk of both outcomes (eg, severe injury and cesarean risk: HR 1.53, CI 1.29-1.81 v. nonsevere: HR 1.01, CI 0.92-1.11). Maternal injury was not associated with SMM or stillbirth.

Maternal injury was associated with increased risk of cesarean delivery and placental abruption, particularly for second trimester, severe, and abdominal injury. These findings may inform postinjury clinical care management, focusing on pregnancies most at risk.