Mothers of District babies are less likely to get adequate prenatal care than mothers in any of the nation's 50 largest cities, a new study says, even though D.C. and federal programs offer free medical care to low-income pregnant women.

The study of 1997 birth records by the Annie E. Casey Foundation indicates that 12.3 percent of mothers of babies born in the District that year either failed to get prenatal care or got it late in their pregnancies. That is more than double the rate for pregnant women in other major U.S. cities.

Pregnant women whose yearly income is below 200 percent of the federal poverty level (or about $33,000 for a family of four) are entitled to Medicaid coverage for prenatal and post-natal care. In addition, both the city and at least three nonprofit charities operate outreach programs to inform women of options and try to persuade them to use what is available.

Bill O'Hare, director of the foundation study, said he did not know why the District had the worst prenatal care record of any major city in the country. However, he added that low-income women generally face barriers such as a lack of transportation and information about free health care programs.

D.C. babies also faced other disadvantages in greater numbers than babies in most cities, the study said. In six out of eight areas studied, babies in the District fared worse than babies typically did in other big cities.

D.C. mothers were more likely to be unmarried. Nearly 64 percent of babies in the District were born to unwed mothers, compared with an average of 43 percent in the 50 cities studied.

Babies in the nation's capital also were slightly more likely to be born to teenage mothers. In the District, 15.6 percent of all babies were born to teenage mothers, compared with 14.9 percent on average for all 50 cities.

Moreover, those teenage mothers were more likely to have one or more children already. Nearly a third of the teenagers who had babies in 1997 already had at least one child. On average, 23.8 percent of teenage mothers in the cities already had a child.

Premature birth and low birth weight are indicators of problems that can affect a child's entire life. On both measures, babies in the District fared poorly relative to those in other cities.

In the District, 13.4 percent of babies had low birth weight, compared with 8.8 percent on average in the 50 cities. More than 18 percent of D.C. babies were premature, compared to an average of just over 12 percent for the cities.

District babies did better than average in two areas studied: Their mothers were less likely to smoke, and more likely to have attended school for 12 years.

D.C. health officials did not offer any explanation yesterday for the disparities shown in the report.

The city has tried to address its problems with prenatal care through its Healthy Start Project. It offers prenatal care in community-based clinics, with evening and weekend hours, in the city's poorest wards. It also operates a mobile clinic.

Moreover, several nonprofit organizations also are involved in the effort. Healthy Families D.C., funded by the Freddie Mac Foundation; Mary's Center in Adams-Morgan; and the Healthy Babies Project all reach out to poor mothers. The Healthy Babies Project even visits crack houses and bars, asking whether anyone knows someone who is pregnant.

More of that type of outreach is needed, said Ruth Lubic, director of the D.C. Developing Families Center. The center in Northeast Washington, scheduled to open in June, will include a clinic, a birthing center, a child-care center and the Healthy Babies outreach program.

In other cities where she has worked, Lubic said, mothers often are turned off by the kind of care they receive at city clinics, and so tend to avoid them. "You hear a lot of low-income women saying they weren't treated with dignity," she said.

Drug abuse is also a factor, she added. Prenatal care is a low priority for women seeking their next fix, but it's unclear how many of the women not receiving prenatal care fall into that category, she said.

O'Hare, of the Casey Foundation, said he hopes that cities like the District will look at cities with better outcomes to see if there are solutions that can be replicated.