(283) Severe maternal morbidity associated with cesarean delivery in the periviable period

Objective:
Utilization of cesarean is controversial in the periviable period given the uncertain long-term neonatal benefit and potential risk for severe maternal morbidity (SMM). We sought to characterize the type and rate of SMM by mode of delivery among periviable births.


Study Design:
Single-center retrospective cohort study of periviable livebirths (2012-2021). SMM was defined according to Obstetric Care Consensus No.5 (Table 1). SMM events were organized into the following categories: hemorrhagic, hypertension (HTN)/neurologic, renal, sepsis, pulmonary, cardiac, ICU, surgical, and anesthesia complications. Differences in SMM between delivery cohorts were compared using t-test and chi square. Subgroup analyses were performed measuring SMM by delivery indication (maternal, fetal, or dually indicated). Multivariate logistic regression was performed to estimate association between cesarean and SMM.


Results: Among 289 patients, 152 (52.6%) underwent cesarean. The overall rate of SMM in the cohort was 20.1% (Table). The cesarean group had higher rates obstetric intervention utilization including magnesium for fetal neuroprotection, expectant management of preeclampsia, latency antibiotics, steroids, and fetal monitoring; concordant with the finding of later gestational age at delivery (24.5±0.8 vs 23.0±1.8 wks, p< 0.001). The rate of SMM was higher in the cesarean compared to the vaginal cohort (32.9 vs 5.8%, p< 0.001, aRR 4.6, CI 1.3-15.6). The SMM rates between the cesarean and vaginal cohort varied by SMM category; hemorrhagic (5.9 vs 4.4%, p=0.555), HTN/neurological (20.4 vs 0.7%, p< 0.001), and ICU related SMM (9.2 vs 1.5%, p=0.004; Fig). In subgroup analyses, cesarean had significantly higher SMM rates regardless of delivery indication (maternal, 92.6 vs 20.0%; fetal, 17.3 vs 5.4%; dual, 33.3 vs 5.0%; all p-values < 0.05). 

Conclusion: 1 in 5 women who delivered in the periviable period experienced a SMM. Cesarean was associated with a more than 4-fold increase in SMM. The causal pathway to SMM among periviable births is complex; as cesarean may both contribute to and mitigate SMM in a critically-ill mother.