A study published two years to the day since the overturning of Roe v Wade, which ended the constitutional right to abortion access in the USA, has found that infant deaths rose by much more than expected in the state of Texas in the months following the state’s 2021 ban on abortion in early pregnancy.

Texas state law Senate Bill 8, or SB8, came into effect on September 1, 2021. At the time – more than eight months before the momentous Supreme Court decision Dobbs v Jackson Women’s Health Organization that overturned Roe v Wade – this was the most stringent anti-abortion legislation in the country, outlawing abortion after the point when a fetal heartbeat could be detected. This milestone is reached as early as five or six weeks into a pregnancy, which may be before somebody even suspects they might be pregnant.

There is no exemption for congenital fetal anomalies, or pregnancies resulting from rape or incest, but there is an exception made for “medical emergencies”. The highly controversial act empowers members of the public to take civil action against anyone performing or facilitating an illegal abortion, and the threat of litigation meant providers felt unable to continue offering pregnancy termination services in the state even while the 50-year precedent set by Roe v Wade remained in place.

Other states sought to copy Texas’ example, and after Dobbs v Jackson, a flurry of other abortion restrictions were brought into effect. Researchers are therefore very interested in the impact that SB8 has had since 2021.

The new study, led by a team at Johns Hopkins Bloomberg School of Public Health, examined the number of infant and neonatal deaths in Texas between March and December 2022, the first set of pregnancies under a fully enacted SB8.

The researchers estimate that there were 216 excess deaths of infants under 1 year old during this period, which would not have occurred had the law not been in place. The total number was 1,913, representing an increase of 12.7 percent over the expected 1,692.

The pattern with neonatal deaths – that is, death in the first 28 days of life – was similar, with an estimated 145 excess deaths.

“Our study is particularly relevant given the June 2022 Dobbs Supreme Court decision that returned abortion lawmaking to states and subsequent rollbacks of reproductive rights in many states,” said Dr Alison Gemmill, one of the study’s lead authors, in a statement. “These findings suggest that restrictive abortion policies may have important unintended consequences in terms of infant health and the associated trauma to families and medical costs.”

The data also showed an unusual increase in the number of deaths of babies with congenital anomalies. Before SB8, it was possible to seek a termination in the state of Texas at up to 20 weeks of pregnancy if a medical issue with the fetus was detected.

Infant deaths due to congenital anomalies increased by 22.9 percent in Texas during the study period – this is compared to an increase of 3.1 percent in the rest of the US. Accidental deaths also went up by 21 percent in Texas, and by only 1 percent in the rest of the country, based on an analysis of 28 states for which data were available.

“Our results suggest that restrictive abortion policies that limit pregnant people’s ability to terminate pregnancies, particularly those with fetal abnormalities diagnosed later in pregnancy, may lead to increases in infant mortality,” said co-lead author Dr Suzanne Bell.

The study has some limitations. It was difficult to exactly pinpoint pregnancies that had been affected by SB8 as the gestational ages of infants dying in 2022 were not available. There was also a lack of sociodemographic data, so it’s unclear whether the increased deaths were disproportionately seen in certain communities.

However, the results align with previous data suggesting that stricter limits on abortion access are associated with excess infant mortality.

Bell added, “These findings make clear the potentially devastating consequences abortion bans can have on pregnant people and families who are unable to overcome barriers to this essential reproductive health service.”

The study is published in the journal JAMA Pediatrics.