In the 18 months after the U.S. Supreme Court overturned Roe v. Wade, which led to more than a dozen states adopting near-total bans on abortion, hundreds more babies died than expected, new research has found.

The study, conducted by researchers at Ohio State University and published Monday in Jama Pediatrics, compared child mortality data from the months before Roe's downfall with data from afterward. They found that overall child mortality increased by 7% in October 2022, March 2023 and April 2023.

On average over these months, there were about 247 more infant deaths per month than expected, researchers said. In six of those 18 months, mortality among infants with congenital anomalies increased by 10%. During these months there were around 210 more deaths per month than expected.

The child mortality rate has never fallen lower than expected.

This study is the latest to examine how Roe's death affected the health of babies. In June, another study estimated that the number of infants who died in their first year of life rose 13% after Texas banned abortions after about six weeks of pregnancy.

The researchers behind this study also found that there was a sharp increase in deaths among infants with congenital anomalies.

These conditions can often be detected in the womb and, in states where abortion is still legal, lead women to terminate their pregnancies, particularly because they may be incompatible with life. However, for people living under an abortion ban, this may no longer be an option.

“Any infant death is tragic, but on top of that there is the situation of this pregnant person, knowing that she is carrying a fetus that is incompatible with life, when previously she might have had the option of terminating the pregnancy,” Alison Gemmill, the lead author of the June study and an assistant professor at the Johns Hopkins Bloomberg School of Public Health, told the Guardian following the publication of her study.

The study released Monday did not break down infant mortality rates by state.

Abortion bans also endanger the health of pregnant women. Dozens of women across the country said they were denied medically necessary abortions because of extremely restrictive bans.

Two women, Amber Nicole Thurman and Candi Miller, died in Georgia after being unable to access legal abortions due to the state's six-week abortion ban, ProPublica reported.