A new study comparing deaths of pregnant people and of those who have an abortion show that risk of death due to pregnancy is three times higher than previously estimated.

The findings suggest that abortion bans force pregnant people who otherwise would have sought abortion care to take on the substantially increased health risks associated with continued pregnancy, including hemorrhage and high blood pressure. The study, led by researchers at Brown and the University of Maryland, was published in JAMA Network Open.

“Our findings underscore how dangerous abortion bans are for pregnant people: forcing someone to continue a pregnancy puts them at a dramatically higher risk of death—along with so many other harms,” says author Benjamin Brown ’08 MD’12, MS, the Mimi Pichey Assistant Professor of Obstetrics and Gynecology. “The data also highlight the urgent need to lower mortality rates for all pregnant, birthing, and postpartum people.”

Brown, an ob/gyn with a subspecialty in complex family planning, connected with lead author Maria Steenland, SD, an assistant professor at UMD’s School of Public Health, when she was an assistant professor at Brown’s School of Public Health.

“It is widely understood by scientists that continuing a pregnancy carries a much higher risk of death than having an abortion,” Steenland says. “Our new analysis shows that it is far more dangerous to be pregnant than to have an abortion, and this gap in mortality risk is even larger than previously recognized.”

The study found that the mortality risk from pregnancy (including up to one year postpartum) is 44 to 70 times higher than the mortality risk from abortion—three times higher than previously estimated. Prior to this study, a commonly cited statistic was that the risk of death associated with childbirth is approximately 14 times higher than that of abortion. This statistic was based on data from 1998 to 2005, and during that timeframe, mortality rates for people with ongoing pregnancies have been estimated to be between 8.8 and 14.5 per 100,000 live births. The current study, using data from 2018 to 2021, found an annual average of 32.3 maternal deaths per 100,000 live births, with the highest rate of 43.9 occurring in 2021.

The study defined pregnancy-related deaths as occurring during pregnancy or within one year from the end of pregnancy. They were further identified by hundreds of specific underlying pregnancy-related causes such as hypertension disorders, obstetric hemorrhage, complications from chronic heart and kidney disease, and various infections occurring while pregnant.

One major factor involved in the recent analysis was the availability of new data. In 2003, a pregnancy checkbox option was added to death certificates to indicate whether the deceased person was pregnant. When the checkbox was fully implemented in 2018, it addressed prior undercounting of maternal deaths but also led to a potential problem of overcounting, where the cause of death for the deceased person may have been misclassified as being related to pregnancy.

To calculate pregnancy-related death rates, the research team analyzed data on deaths and births (live and stillbirth) from the US National Vital Statistics System, as well as abortion-related deaths from the Pregnancy Mortality Surveillance System between 2018 to 2021. Data on the number of abortions during that time came from the Guttmacher Institute, a nonpartisan research nonprofit that monitors abortion surveillance data.

To account for possible overcounting of maternal deaths, the study removed nonspecific causes of pregnancy-related mortality, such as “other specified pregnancy-related conditions,” which prior research showed was likely to be misclassified. The study also excluded deaths from COVID-19 and deaths of people whose pregnancy ended because of miscarriage or self-induced abortion.

“Even with this conservative approach to calculating maternal mortality, we found the risk of dying from pregnancy and childbirth far exceeded the risk of dying from abortion,” says study author Marie Thoma, PhD, a reproductive and perinatal epidemiologist and an associate professor at the University of Maryland. “People deserve access to updated information about these comparative risks and policies that reflect these realities.”

The risk of death due to abortion has decreased since previous studies were conducted, most likely because more people who have an abortion have it earlier in the pregnancy, which is generally safer, the researchers say. However, they add, increased restrictions to abortion access will likely affect maternal health going forward.