(CNN) A major part of the Affordable Care Act -- the expansion of Medicaid -- may be linked to lower rates of women dying in pregnancy, childbirth or within six weeks of delivery, a new study suggests.

From 2006 to 2017, states that expanded Medicaid were significantly associated with lower rates of maternal death by about 7 deaths per 100,000 live births, relative to states that did not expand, according to the study published last week in the journal Women's Health Issues

"The largest reduction was among non-Hispanic black women, which I think is particularly significant because they have such a higher maternal mortality rate than Hispanic or non-Hispanic white women," said study author Erica Eliason, a doctoral student researcher at Columbia University's Columbia Population Research Center in New York.

"So the fact that it's having the largest effect among that group could mean that it's reducing the disparities in maternal mortality as well," she said.

Eligible Americans can qualify for Medicaid based on income, household size, disability, family status and other factors, but the ACA allows states to expand Medicaid eligibility so that residents can qualify based solely on whether their household income level is a certain percentage below the federal poverty line.

The new study included data on maternal deaths across the United States from the National Center for Health Statistics and compared maternal death rates in states that implemented Medicaid expansion between 2006 and 2017 to those that did not.

The data showed that following Medicaid expansion implementation, the maternal death rate dropped in states that expanded the program compared to those that did not.

"Trends in maternal mortality among expansion and non- expansion states have a slight separation that starts after the early Medicaid expansion period, with effects seen as early as 2012," Eliason wrote in the study. The Affordable Care Act was signed into law in 2010.

"This separation continues throughout the duration of the study period, with a larger divergence occurring between expansion and non-expansion states beginning in 2015, the year after the majority of expansion states extended their Medicaid programs," she wrote. "These results suggest that Medicaid expansion could be contributing to a relative decrease in the maternal mortality ratio in the United States compared to non-expansion states, while maternal mortality overall continues to rise."

When it comes to Medicaid, the American College of Obstetricians and Gynecologists has supported extending coverage for women to one year after childbirth in order to reduce risk of complications, health emergencies and maternal deaths that can occur after giving birth.

Medicaid coverage typically is offered to women for up to 60 days after delivery. The House Energy and Commerce Committee in November advanced new legislation to offer incentives to states to continue Medicaid coverage for women for one year after delivery.

"This legislation would help ensure that moms receive care beyond that period for serious health conditions, including cardiovascular disease, postpartum depression, and opioid use, and close a huge gap in women's health coverage during a time in which the Centers for Disease Control and Prevention show one-third of preventable maternal deaths occur," ACOG President Dr. Ted Anderson said in a written statement in November.

Now ACOG looks forward "to collaborating with all members of Congress to bring these bills to the floor of the House and Senate," he said in the statement.

The extension of Medicaid coverage for women up to one year postpartum also has been an area of research that Eliason hopes to focus on next.

"Women are losing coverage 60 days after childbirth and that is not enough health insurance access for women who recently gave birth," she said. "I'm really hoping my study can make a difference."

In 2018, the year with the most recent national data, a total of 658 women in the United States died while pregnant or within 42 days of the end of pregnancy, according to data released by the CDC's National Center for Health Statistics in January.

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The "most striking findings are the high overall mortality rate and large disparities -- nothing new, but still deeply troubling," Lu said about the CDC data.

"In 21st century America, in the richest and most powerful nation on Earth, no woman should ever die from pregnancy and childbirth: 658 deaths are 658 too many," he said. "I believe we can cut maternal mortality in half by 2025, and eradicate maternal deaths in the US by 2050, by doing three things: learn from every maternal death, assure quality and safety of maternity care for all women and improve women's health across their life course."