Extending the monitoring period for severe pregnancy complications showed more than 40% of cases were missed using traditional delivery-focused monitoring, according to new research published in CMAJ (Canadian Medical Association Journal) that extended monitoring from conception to 6 weeks postpartum.
Severe maternal morbidity (SMM) describes complications in pregnancy that can result in death, extended hospitalization, or long-term disability. Current practices in Canada monitor and report cases of SMM during labour and delivery, but evidence suggests extending the surveillance period from conception to 6 weeks postpartum could have benefits and would align with guidance from the World Health Organization.
These findings also align with coroner’s data from Ontario that show most maternal deaths occur outside the labour and delivery window, with 47% in the prenatal period and 46% postpartum.
Led by researchers from McMaster University, Hamilton Health Sciences, and St. Joseph’s Healthcare Hamilton, the study looked at all births from 20 weeks’ gestation in Ontario, Canada, between April 1, 2012, and March 31, 2021, using linked administrative and clinical registry data from ICES, an independent, not-for-profit research and analytics institute. The research team extended the surveillance period from conception to 6 weeks postpartum, encompassing a much wider time frame. Of the almost 1.1 million births, the rate of SMM was 27.24 per 1000 births, which translates to nearly 10 000 people in Canada experiencing these severe maternal complications every year.
“Severe maternal complications aren’t just a delivery room issue — they occur across pregnancy and after birth, and many first appear in emergency departments rather than obstetric units,” says Dr. Giulia Muraca, senior author and a perinatal epidemiologist and an associate professor in the Departments of Obstetrics and Gynecology and Health Research Methods, McMaster University, Hamilton, Ontario. “Improving maternal safety requires a whole-system approach, involving emergency care, primary care, maternity care teams, and postpartum follow-up.”
Study findings:
• Severe hemorrhage, severe preeclampsia, and sepsis were the most common types of SMM; acute appendicitis and sepsis were the most common SMM events in the prenatal and postpartum periods, respectively.
• Sixteen per cent of SMM events occurred in the prenatal period, 55% during labour and delivery, and 29% in the 6-week postpartum period.
• Of all those who experienced an SMM event, 19% visited an emergency department, mostly in the pre- and postnatal periods.
• Risk factors for SMM vary depending on when the event occurred. For example, complication rates during labour and delivery and in the postpartum period were highest among the youngest and oldest parents, but pregnancy complications before labour were especially common among those aged 15–24 years.
• Common factors associated with SMM in all periods include first pregnancy, maternal race, pre-existing medical conditions, multiple fetus pregnancies, immigrant status, low income, rural/remote residence, substance use during pregnancy, and assault.
• Type 1 diabetes had the strongest association with prenatal SMM.
“Our findings, combined with the knowledge that most maternal deaths do not occur during delivery, highlight that focusing only on the intrapartum period will not adequately serve to recognize, prevent, or respond to SMM (and maternal deaths),” the authors write. “As a result, outpatient surveillance to identify and prevent maternal sepsis is warranted, such as postpartum home monitoring (e.g., heart rate, blood pressure) for individuals at increased risk.”
The authors emphasize that SMM is an important medical and public health problem that needs support, and that extending the surveillance period in pregnancy will capture many more preventable cases of severe maternal illness.
“These findings underscore the importance of accessible and timely postpartum care, particularly among people with higher SMM risk. Suboptimal access to primary care and decreasing access to ambulatory obstetrical care during the postpartum period in Ontario leaves many individuals without adequate care after childbirth.” nH
“Severe maternal morbidity from conception to 6 weeks postpartum in Ontario: a population-based, longitudinal cohort study” is published March 16, 2026.