Georgia, Ohio, Missouri, Louisiana, Alabama and Mississippi have in recent weeks passed some of the most restrictive abortion policies in the nation. But they have other things in common, too.

Four of those states have also declined to expand Medicaid under the Affordable Care Act, leaving a large number of pregnant women without health care.

The most startling similarity shared by all six states, however, is this: They all tend to have the highest rates of infant mortality in the nation.

"If the mother isn’t healthy, it’s unlikely the baby will be healthy," said Dr. Laura Riley, chair of obstetrics and gynecology at Weill Cornell Medicine and NewYork-Presbyterian.

On Friday, Missouri's governor signed a bill into law that would ban ending a pregnancy after about eight weeks gestation. Georgia, Ohio and Mississippi have also passed so-called "heartbeat" laws prohibiting abortions after about six weeks gestation, before many women know they’re pregnant. A similar bill is making its way through the Louisiana Legislature, and that state’s governor has indicated he will sign it into law. Alabama recently passed the most stringent law, banning almost all abortions at any time of gestation, except when a mother’s life is in jeopardy.

The intent for many anti-abortion efforts in these states is to overturn Roe v. Wade, the landmark 1973 U.S. Supreme Court decision that legalized abortion.

“We’re seeing these bans in states where already there are harsh barriers to reproductive health care, and where we know they have negative health care outcomes,” said Jacqueline Ayers, vice president of government relations and public policy at the Planned Parenthood Action Fund. On Friday, Planned Parenthood and the American Civil Liberties Union announced they filed a federal lawsuit over Alabama's ban.

In fact, babies carried to term are dying in those states more frequently than in many others.

The average national infant mortality rate in 2017 was 5.8 per 1,000 live births, according to data from the Centers for Disease Control and Prevention. Missouri's was higher at 6.2 infant deaths per 1,000 live births. Louisiana’s was at 7.1 infant deaths per 1,000 live births. Georgia and Ohio’s rates were at 7.2 deaths per 1,000 live births, and Alabama’s reached 7.4 deaths per 1,000 births.

But Mississippi had the highest infant mortality rate in the nation — at 8.6 deaths per 1,000 live births.

In addition, Alabama, Georgia, Mississippi and Missouri did not expand Medicaid under the ACA, creating gaps in health care coverage for women of childbearing age, according to a new study from Georgetown University that examined links between Medicaid expansion and insurance.

"If states would expand Medicaid coverage, they would improve the health of mothers and babies and save lives."

"The uninsured rate for women of childbearing age is nearly twice as high in states that have not expanded Medicaid," said Adam Searing, a research professor at the Georgetown University Center for Children and Families. "That means a lot more women who don’t have health coverage before they get pregnant or after they have their children."

"If states would expand Medicaid coverage, they would improve the health of mothers and babies and save lives," he said.

Dr. Sarah Horvath of the American College of Obstetricians and Gynecologists agrees.

"Comprehensive medical care gives women an awareness of healthy lifestyles before pregnancy," Horvath told NBC News.

The connection between high infant mortality and severe restrictions on abortion are correlational, meaning a ban on abortions can't be proven to cause maternal or infant mortality or other negative health problems. But the leading causes of newborn death — which include preterm birth, birth defects and other pregnancy complications — are closely connected to a pregnant woman's access to prenatal health care.

In fact, the March of Dimes gave Louisiana, Mississippi and Alabama all failing grades in its 2018 Premature Birth Report Cards. Georgia received a “D.”

High maternal mortality rates

The same states also have high rates of mothers dying during labor and after childbirth. About 700 women die from pregnancy-related causes every year and more than half of those deaths are preventable, according to a recent CDC report on maternal mortality.

Particularly striking is the rate of pregnant women and new mothers dying in Georgia. That state ranked 48th out of 50 in a measure of maternal mortality in the 2018 America’s Health Rankings from the United Health Foundation, with 46.2 deaths per 100,000 live births. Mississippi and Alabama’s rankings were better: at 32nd and 7th, respectively.

But Missouri and Louisiana joined Georgia near the bottom. Missouri ranked 42nd out of 50, and Louisiana was just above Georgia in the Health Rankings for maternal mortality, at 47th out of 50, with 44.8 deaths per 100,000 live births.

“You see areas of the country where access to a broad range of health care is either lacking or where great disparities exist,” said Megan Donovan, a senior policy manager at the Guttmacher Institute, a group that studies reproductive rights.

The March of Dimes report found that in Mississippi, the preterm birth rate among African American women is 44 percent higher than the rate of all other women. In Georgia, the rate is 46 percent higher than women of other races.

And in both Alabama and Louisiana, the preterm birth rate among black women is 51 percent higher.

The reasons for the disparities are complex.

"It may be that years of racism and classism adversely affects one’s health and one’s ability to accept healthcare."

"There appears to be an influence of unconscious bias and racism. It may be that years of racism and classism adversely affects one’s health and one’s ability to accept health care," Riley said.

A 2017 report from the Center for Reproductive Rights and Ibis Reproductive Health found that the more abortion constraints a state passed — such as mandatory waiting periods, counseling, gestation age limits and restrictions on abortion health care coverage — the fewer evidence-based supportive policies it had for women and children.

According to the report, that includes expanding Medicaid, family and medical leave, as well as mandatory sex education.

On the other side, states actively passing protections for abortion and women’s reproductive rights also have some of the lowest rates of infant mortality in the country, Donovan said.

Lawmakers in Vermont recently passed a measure that would ban that state’s government from interfering in reproductive and abortion rights. And it looks as if it will become law. Vermont Gov. Phil Scott, a Republican, said he had ruled out vetoing the bill.

Vermont’s infant mortality rate is low, at 4.8 deaths per 1,000 live births, according to the CDC.

The data show New York’s infant mortality rate is even lower, at 4.6 deaths per 1,000 live births. That state passed the Reproductive Health Act earlier this year, which includes a provision permitting late-term abortions when a woman’s health is in danger.

In Massachusetts, the infant mortality rate is 3.7 per 1,000 live births. That state’s Legislature is considering a bill that would expand abortion access by removing the requirement for minors to get parental consent, and allow abortions later in a pregnancy under certain conditions.

“It remains to be seen what will be successful where, but there are advocates and policymakers and states in a position to do positive things to expand and protect access,” Donovan said. “This will be all the more important as other states go in the opposite direction.”