In Massachusetts, a quietly powerful experiment in maternal health is unfolding inside the state's Medicaid program — and early results suggest that simply measuring care can change it. A new Boston University study found that when the state required health networks to track specific maternal health metrics, those networks built new programs to meet them, improving the quality of care for pregnant and postpartum patients.
The backdrop is urgent. Medicaid is the largest insurance program for maternity care in the United States, and the country's maternal mortality rates far outpace those of other wealthy nations — with Black and Hispanic populations hit hardest. So how one of the biggest insurers of birth chooses to measure and pay for care matters enormously.
The researchers, led by Dr. Shannon Ogden of the Boston University School of Public Health, interviewed leaders, clinicians and care coordinators from six of Massachusetts' 17 Medicaid Accountable Care Organizations (ACOs) between 2018 and 2024. An ACO — short for Accountable Care Organization — is a network of doctors and hospitals that band together, rewarded for keeping patients healthier rather than simply treating them when they get sick. Their work, published in The Milbank Quarterly, is the first qualitative study of how Medicaid ACOs put maternal health initiatives into practice across multiple program periods.
The finding was clear: metrics matter. When Massachusetts attached specific maternal health requirements to ACO contracts — from timely prenatal care to postpartum depression screening — the organizations responded by adapting or building programs to hit those targets and track how engaged patients were. "Our findings showed that metrics matter; instituting maternal health-related metrics at an organizational level does prompt ACOs and health care organizations to develop the programs needed to meet those metrics and track patients' engagement," Ogden said.
But the picture isn't all rosy. ACOs faced formidable challenges in meeting the requirements, and the difficulties differed depending on the network's design — whether it was built around a primary care model or a health system-based model. The researchers also note that the first waiver period required only a single maternal health metric: timely prenatal care. And leaders identified remaining gaps in care, a reminder that there is still work to be done.
The study builds on earlier research linking Medicaid ACOs to improvements in maternity care engagement and quality, though not yet in health outcomes. MassHealth, the state's Medicaid program, launched its first ACO in 2018 and renewed and expanded the effort under a second five-year waiver in 2023.
Senior author Dr. Lois McCloskey framed the challenge plainly: sustainable change needs more than targets. "Resources must be sufficient. It takes tangible resources to make meaningful change," she said. As Massachusetts presses forward — and other states watch closely — the lesson is that measuring maternal health is a powerful first step, but true equity will require the funding and coordination to back it up.