In the 15 years since Sussana Bio-Nyarko began working as an advocate for pregnant women in Worcester, much has changed in her home city.

Not only has Worcester experienced economic and demographic growth over the last decade, but it has also seen a decrease in the disparity for black and white families when it comes to maternal and infant health.

Worcester has had persistently higher rates of infant mortality than similar cities in Massachusetts, and until recently, there was a bigger gap in these rates for babies of different races in Worcester than in the state and nationwide.

In 2001, black babies in Worcester were over six times more likely than white babies to die in their first year of life, with an infant mortality rate of 26.8 out of 1,000 live births. In 2016, the infant mortality rate for black babies had fallen to 8.6 — closer to the state average. But black babies in Worcester and statewide are still more than twice as likely as white babies to die in their first year of life, and advocates say there’s still more work to do.

Of all the infant deaths in Worcester, about half are from mothers not born in the continental U.S. The statistics show the risk is greatest for immigrants of color.

That’s where Bio-Nyarko comes in. She works for the Worcester Healthy Baby Collaborative, which formed in the 1990s in response to the stark disparities in infant mortality rates across the city’s racial groups. Bio-Nyarko, who worked as a midwife in Ghana for over a decade before coming to the U.S., is now a community advocate for pregnant African immigrant women.

The collaborative’s project to reach African immigrant women is named Nhyira Ba, which means ‘Blessed Baby’ in Twi.

“When you say ‘Nhyira Ba’, it means the baby is very precious for you,” said Bio-Nyarko. “Before you get a precious baby, you have to take care of the pregnancy first.”

Bio-Nykarko said she has worked with hundreds of patients over the years, mostly from Ghana, Nigeria, Liberia and Congo. She helps black immigrant women navigate the city’s health system.

“Sometimes they come with pregnancy [and] they don’t have anybody,” said Bio-Nyarko. “We have to help introduce them to the community and show them where to get their resources.”

The director of the Healthy Baby Collaborative, family physician Sara Shields, said some of the most important factors in these inequities — many of which are the result of structural inequalities in the U.S. and in their countries of origin — are difficult to measure.

“There’s inter-generational, multi-generational poverty, experiences of racism and maternal stress,” said Shields. “These are things that we don’t have a good medical model for.”

Shields added that many immigrant women work multiple jobs to send money home, and this stress can be a factor in premature labor, which is the leading cause of infant death in Worcester — babies born too small to survive.

In the face of this stark disparity and its long list of causes, Shields said the collaborative’s role is to listen to what community members say they need. They meet in non-medical settings, like community centers or churches, to plan programs.

Bio-Nyarko said her own experience as an immigrant helps her to connect with her clients.

“They feel like they are new, and they don’t know nothing” she said. “I tell them, ‘We are all new, we are all strangers here, so don’t feel bad.’”

Bio-Nyarko said clients feel better when they see the color of her skin and hear her voice. And she helps her clients access healthy food, prepare for birth and navigate the U.S. health care system, among other services. The goal of the project is to create equal health outcomes regardless of race.

Achiamaah Serebour is one of Bio-Nyarko’s clients. She has an 18-month-old son named Curtis Nana Duncan. Serebour says having an advocate helped her. She refers to Bio-Nyarko as “Ma Sussana.”

“She’s from Ghana and she’s from way back home,” said Sarabour. “She knows my experience. When I met her, I said, ‘Oh, God, thank you,’ because it’s like I met my mom.”

When Curtis was born, Serebour received a “Baby Box” from the Healthy Baby Collaborative, a sturdy cardboard box, which could be used as a place for Curtis to sleep. When Serebour received the box, it was filled with educational materials about nutrition, postpartum depression, mental health and breastfeeding. It also included baby clothes and a colorful picture book without words, which is a pre-literacy tool that can be used no matter the mother's language.

Though the numbers have gotten a lot better for black and African-immigrant women in Worcester since the project started 20 years ago, Shields says there’s more to do.

“Our work is not done,” said Shields. “Risk factors of poverty, immigration, acculturation and racism still exist, and we can’t really rest on our laurels.”

In fact, despite the relative success with Nhyira Ba for black families, Worcester has recently seen a significant uptick in the Hispanic infant mortality rate. It’s now three times higher than for white babies and far exceeds the state average for Hispanic babies.

The collaborative is now working with local Latino families to find solutions. Shields said community members mentioned stressors like unemployment and poverty.

“Our goal is making sure that people of every community are represented at our table,” said Shields. “We’re trying to get more representation in our group, and we want to make sure that we have really good listening ears around what the community wants us to know.”

Correction: An earlier version of this story incorrectly stated that Sara Shields is an obstetrician. She is a family physician. This story has also been updated to reflect the correct spelling of the Worcester Healthy Baby Collaborative's project to reach African immigrant women. It is Nhyira Ba, not Nyshira Ba.