(1036) Severe Maternal Morbidity Associated With Timing and Absence of Prenatal Care

To examine the association between timing and absence of prenatal care and the risk of severe maternal morbidity (SMM)

Study Design:

This population-based, retrospective cohort study utilized the California Office of Statewide Health Planning and Development Linked Birth File with hospital discharge diagnoses coded in the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) between 2007 and 2012. The primary outcome was SMM, defined as any of the 25 peripartum conditions listed by the Centers for Disease Control and Prevention. Prenatal care was categorized as no care, early care (≤14 weeks gestation), or other care ( >14 weeks or unspecified). Chi-square tests compared SMM incidence across care groups, and Cox proportional hazards models estimated risk relative to no care. A cumulative hazard plot was generated to illustrate timing of SMM events by prenatal care group.

Results:
Of the 3,034,753 pregnancies analyzed, 44,270 (1.46%) were complicated by SMM. The highest burden occurred in pregnancies without prenatal care, with 48 of 284 affected (16.9%). By comparison, SMM was seen in 3,441 of 173,605 pregnancies (1.98%) in women with other care and in 40,781 of 2,860,864 pregnancies (1.43%) in those who initiated care in the first trimester. Cox modeling demonstrated that any prenatal care was highly protective compared with none. Early care was associated with the lowest risk of SMM (HR 0.0148; 95% CI 0.0110–0.0199), and other care also conferred substantial protection (HR 0.0217; 95% CI 0.0161–0.0291; both p< 0.001). Cumulative hazard curves demonstrated that SMM risk rose after 30 weeks in pregnancies without prenatal care. In contrast, SMM risk stayed low throughout gestation for those receiving care, with early care providing the lowest risk.

Conclusion:

Absence of prenatal care is strongly associated with SMM, whereas receiving any care is highly protective. Early care offers the lowest risk, with a slight advantage over other care. These findings highlight the importance of prenatal care and early engagement to prevent life‑threatening maternal complications.