There is a significant risk of recurrent severe maternal morbidity (SMM) in subsequent pregnancies following an initial incidence, according to a recent study published in the American Journal of Obstetrics & Gynecology.
Takeaways
- The study emphasizes a notable risk of recurrent severe maternal morbidity in subsequent pregnancies following an initial incidence. This highlights the importance of understanding and addressing this risk for improved maternal health outcomes.
- Severe maternal morbidity encompasses a range of life-threatening complications, including eclampsia, severe obstetrical hemorrhage, and other serious disorders. The study identifies different types of SMM and their varied associations with the risk of recurrence.
- SMM is associated with over half of all maternal mortalities, and the study notes an increasing trend in SMM rates over time. This underlines the ongoing importance of maternal health initiatives and interventions to address and mitigate the risks associated with severe maternal morbidity.
- Women with SMM not only face risks during pregnancy but also experience longer delivery hospitalizations and heightened risks of cardiovascular disease and all-cause mortality. This underscores the need for comprehensive postpartum care and ongoing monitoring of maternal health beyond the immediate post-delivery period.
- The findings emphasize the necessity of understanding recurrent SMM to inform decision-making about future pregnancies. The study's results, indicating increased risks associated with various types of initial SMM, highlight the importance of dedicated counseling before subsequent pregnancies to support informed and personalized maternal care.
SMM includes several life-threatening complications in mothers, including eclampsia and severe obstetrical hemorrhage. SMM is associated with over half of all maternal mortalities, and rates of SMM are increasing over time. Patients with SMM also experience longer delivery hospitalizations and increased risks of cardiovascular disease and all-cause mortality.
Understanding about recurrent SMM is necessary to improve decision-making about future pregnancies. However, while preeclampsia and postpartum hemorrhage often recur in subsequent pregnancies, there is little information about recurrent SMM.
To evaluate the association between SMM in an initial delivery and SMM risk in a subsequent delivery, investigators conducted a longitudinal cohort study. Pregnant women with at least 2 documented deliveries between 1989 and 2021 in Quebec, Canada were included in the analysis.
Exclusion criteria included having only 1 delivery or dying at the first delivery and up to 1 year postpartum, receiving a pregnancy or tubal ligation, pregnancies ending before 20 weeks’ gestation, twin or higher-order gestations in the first recorded delivery, and missing health insurance numbers.
Initial SMM exposure was defined using the Canadian Perinatal Surveillance System (CPSS) criteria, with SMM from 20 weeks’ gestation up to 42 days postpartum recorded. As the analysis focused on life-threatening conditions, hypertensive heart disease, HIV, and hysterectomy were excluded.
SMM types analyzed included severe obstetrical hemorrhage, severe preeclampsia or eclampsia, cerebrovascular accidents, acute heart failure, acute renal failure or dialysis, shock, embolism, uterine rupture, sepsis, disseminated intravascular coagulation, assisted ventilation, surgical complications, intensive care unit admission, and other serious disorders.
Composite SMM in the second delivery, identified using the same criteria as the initial delivery, was recorded as the primary outcome of the analysis. Covariates included maternal age, comorbid conditions, substance use disorders during pregnancy, and time period at delivery.
There were 819,375 with 2 or more recorded deliveries during the time period, 25,873 of whom experienced SMM during the first delivery. These women were more often aged over 35 years, had preexisting comorbidities, and were socioeconomically deprived.
The rates of subsequent SMM were 65.2 per 1000 deliveries for women with an SMM during their first delivery and 20.3 per 1000 deliveries for those without an initial SMM. Having 1 SMM type in the initial delivery was associated with an adjusted risk ratio (aRR) for SMM recurrence of 2.94, 2 types an aRR of 4.06, and 3 or more types an aRR of 5.50.
Subsequent SMM risk increased regardless of initial SMM type, but cardiac arrest had the strongest aRR of 7.27, followed by uterine rupture with an aRR of 6.22. Required assisted ventilation or intensive care unit addition in the initial delivery increased subsequent SMM risk 4-fold, and severe hemorrhage, severe preeclampsia, shock, embolism, and disseminated intravascular coagulation increased subsequent SMM risk 3-fold.
These results indicated SMM in the initial delivery is associated with increased risks of recurrent SMM in subsequent delivery. Investigators concluded these results highlight the importance of dedicated counseling before a subsequent pregnancy.
Reference
Ukah UV, Platt RW, Auger N, et al. Risk of recurrent severe maternal morbidity: a population-based study. Am J Obstet Gynecol. 2023;229:545.e1-11. doi:10.1016/j.ajog.2023.06.010
