For many families, pregnancy care focuses heavily on labor and delivery. Realistically, birth is the major milestone that everyone prepares for and is often seen as the moment when risk peaks. But a major new Canadian study shows that view is too narrow. Some of the most serious, potentially life-threatening complications associated with pregnancy occur before labor begins and after a parent has already given birth.
This is the main message from a new study published in CMAJ on March 16, 2026, led by researchers from McMaster University, Hamilton Health Sciences and St. Joseph’s Healthcare Hamilton. The team looked at more than 1 million births in Ontario between 2012 and 2021 and found that severe maternal morbidity, or SMM, affected nearly 3 per cent of pregnancies from conception to six weeks postpartum. SMM includes major complications such as severe bleeding, sepsis, acute renal failure, severe preeclampsia, and maternal ICU admission. These are not routine pregnancy issues. They are the kinds of events that can threaten a person’s life or long-term health.
Among 1,095,228 births, the researchers identified 29,832 pregnancies that involved at least one major maternal morbidity event. That works out to a rate of 27.24 per 1,000 births. If the same rate were applied across Canada, the authors estimate that approximately 9,720 people per year could experience one of these serious complications.
What makes the findings particularly important is when these complications occurred. About 55 percent occurred during labor and delivery, but 15.63 percent occurred before labor began and 29.34 percent occurred at six weeks after birth. In other words, about 40 percent of cases of severe maternal morbidity occurred outside the window on which standard surveillance systems tend to focus.
This means that much of the serious maternal risk unfolds outside the delivery room. It also means that if the health care system mainly monitors for complications during childbirth, it may miss warning signs earlier in pregnancy and after families have already gone home with a newborn.
The study also found that the most common complications changed by stage of pregnancy. During pregnancy, before delivery, the most common serious problem was acute abdomen, which was largely due to acute appendicitis. During labor, severe bleeding was the main problem. After birth, sepsis was the main cause of serious maternal illness.
This change is important because it shows that maternal health is not a single period of risk with a single set of concerns. The complications that are most likely to happen during pregnancy are not the same as those that are most likely to happen after a baby is born. Families and providers need to think bigger than just work.
The prenatal findings are especially striking because discomfort in pregnancy can easily blur the line between what feels normal and what doesn’t. The researchers found that about 1 in 500 pregnancies involved acute appendicitis before delivery, which they note is higher than estimates from previous population-based studies. If left untreated, appendicitis in pregnancy can lead to serious complications such as perforation, infection, pregnancy loss, premature birth and sepsis.
Postpartum findings are equally alarming. Sepsis accounted for almost half of the major postpartum maternal morbidity events. This is important because the postpartum period is often viewed as a time of recovery rather than an active period of medical risk. Once a baby is born, attention quickly shifts to feeding, sleeping and caring for the newborn. Parents’ symptoms may end up being minimal, even when something more serious develops.
This study is a reminder that giving birth does not mean the risk has passed. A fever, unusual weakness, chills, severe pain, or a feeling that something is just not right after giving birth should not be dismissed as part of normal exhaustion. The postpartum period may seem calmer from the outside, but it can carry significant health risks.
Another finding of the study is where these complications first appeared. Serious antepartum and postnatal events were significantly more likely to occur in emergency departments than during delivery. The researchers found that 46.07 percent of antepartum events and 40.21 percent of postpartum events involved emergency department presentation. This suggests that many of these complications occur for the first time outside of special obstetric settings.
This has major implications for care. Maternal emergencies are not just the responsibility of labor and delivery units. They may be seen first by emergency physicians, family physicians, clinic providers, nurses, or postpartum care teams. If the system focuses too narrowly on the birth itself, serious symptoms may be recognized too late.
The study also showed that risk factors changed depending on when the complication occurred. Before delivery, severe maternal morbidity was more strongly associated with younger age. Compared to those aged 25 to 34, the odds were significantly higher among teenagers aged 15 to 19 and among those aged 20 to 24. During and after childbirth, the pattern changed, with younger and older parents facing increased risk and especially high risk after childbirth in those aged 40 years and older.
This is worth noting because discussions of maternal risk often focus heavily on older age. This study shows that new parents are not automatically low-risk, especially when it comes to serious complications before labor begins.
The figures also highlight wider inequalities. Severe maternal morbidity was more common among black birth parents, among those living in lower-income areas, and among people living in rural or remote communities. During the prenatal period, low income, rural or remote residence, exposure to drugs and substances in pregnancy, and prior experience of assault were all associated with higher odds of severe maternal morbidity.
Women with type 1 diabetes stood out especially during pregnancy before delivery. At the same time, obesity, chronic hypertension, multiple gestation, and cesarean delivery were also associated with higher rates of severe maternal morbidity overall. The researchers are careful to characterize these as correlations, not proof of direct causation, but they still point to the kinds of patients who may need closer monitoring and better support.
There was also a small but statistically significant increase in the overall rate of severe maternal morbidity during the study period, rising from 26.01 to 27.32 per 1,000 births between 2012 and 2021. Some specific complications, including acute renal failure and hysterectomy, also increased over time.
For families, the value of this research is not to create more fear around pregnancy. It is to give a more honest picture of when danger may occur. Some serious pregnancy-related complications may not begin and end in the delivery room. They can appear months before birth or days after a parent is sent home.
The message for health care providers and policy makers is that maternal health surveillance in Canada needs to be broader. If approximately 40 percent of cases of severe maternal morbidity occur outside of labor and delivery, then there are too many systems missing that primarily monitor intrapartum events.
The researchers argue that improving maternal safety requires a whole-system approach. This includes not only maternity teams, but also emergency departments, primary care, postnatal care teams and other parts of the health system where early warning signs may first appear. They also point to the need for stronger outpatient follow-up and more accessible postpartum care, especially for those at higher risk.
The study is based on Ontario data and has some limitations, including that it focused on births at 20 weeks or more and excluded some people without OHIP coverage. However, its scale is significant and its central finding is hard to ignore: serious maternal complications are not concentrated only in childbirth.
For parents, perhaps the most important takeaway is simple. Pregnancy and postpartum recovery deserve to be treated as real medical periods, not just stepping stones on the road to a healthy baby. If something feels wrong before or after birth, it deserves attention. This study makes it clear that maternal health risks do not follow a neat timetable, and better monitoring throughout pregnancy to delivery could help save lives.
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