An almost complete abortion ban in the US state of Texas has been linked to a rise in infant deaths and in the number of babies born with congenital anomalies.

A study of the birth records across the nation between 2018 and 2022 revealed that infant mortality in Texas rose by 12.7 percent following the implementation of the ban on 1 September 2021.

In addition, deaths attributed to congenital anomalies rose by 22.9 percent. Both of these increases were only found in Texas. For the rest of the US, infant mortality only rose by 1.8 percent for the same time period, and congenital anomaly deaths decreased by 3.1 percent.

The findings, made by a team led by demographer and epidemiologist Alison Gemmill of Johns Hopkins University, suggests that such bans can have very serious and unintended impacts on the lives and health of the community.

"Although replication and further analyses are needed to understand the mechanisms behind these findings," the researchers write, "the results suggest that restrictive abortion policies may have important unintended consequences in terms of trauma to families and medical cost as a result of increases in infant mortality."

The Texas Heartbeat Act, known as Senate Bill 8 or SB8, is a ban on abortion after a fetal heartbeat can be detected, as early as five weeks into pregnancy. There are no exceptions for congenital abnormalities, which are the leading cause of infant death in the US.

The purpose of this bill was to reduce the number of abortions taking place in Texas. An analysis has already found that the birth rate rose in Texas in 2022, with an additional 16,147 births, and a rise in teen pregnancy rates for the first time in 15 years.

A 2022 study found US states that enforced restrictive abortion policies during 1974–2016 saw an increase in the suicide rate for women of reproductive age.

Gemmill and her colleagues, however, wanted to know what other effects SB8 may have had. Specifically, prior observational evidence showed that states with more stringent abortion restrictions had higher infant mortality rates.

So the team dug into publicly available death certificate data from the US National Center for Health Statistics. They were specifically looking at neonatal deaths – those taking place before 28 days of age – and infant deaths, before the age of 1 year, between January 2018 and December 2022.

They also studied the same data from 28 other states, and from this they constructed a synthetic control for Texas, to estimate what the infant mortality rate would have been, had SB8 not been enacted.

The records showed that, in the specified timeframe, there were 102,391 infant deaths in the US, with 10,351 of those in Texas. Between 2021 and 2022, the rate rose from 1,985 to 2,240. That's 255 additional infant deaths in 2022, a total increase of 12.9 percent.

The policy exposure period – infants that could have been conceived not long before or after the implementation of SB8 – was determined to be March to December 2022.

For this period, 1,913 deaths were observed in Texas, compared to the 1,697 expected based on the synthetic Texas control. That's a 12.7 percent increase above the expected mortality rate.

Between 2021 and 2022, there was also a rise in some of the causes of death. Deaths associated with congenital anomalies rose from 445 to 547 – an increase of 22.9 percent. In the rest of the US, the congenital anomaly mortality rate fell.

There was also a Texas-specific increase in the death rates attributed to unintentional injuries, 20.7 percent, compared to the 1.1 percent increase observed in the rest of the US; and necrotizing enterocolitis, an intestinal disease usually seen in premature babies, which rose by 73.3 percent, compared to a 6 percent rise everywhere else.

Since the implementation of SB8, the US Supreme Court has overturned Roe v. Wade, the 1973 landmark ruling that granted constitutional, nationwide access to abortion.

Nearly half the US now has severely restricted or banned abortion; understanding the effects of these rulings is deeply important, the researchers say.

"This study provides some of the first empirical evidence on the association of restrictive abortion policies with infant deaths by using population-based data and a rigorous causal inference technique," they write.

"Our findings suggest increases in infant death, particularly due to congenital anomalies, among infants who would have been in early gestation when SB8 went into effect in Texas."

The research has been published in JAMA Pediatrics.

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