A few more women are forgoing the hospital to give birth at home.

Researchers have found a 20 percent increase in American births at home from 2004 to 2008. Most of the rise was due to an increase in home births among non-Hispanic white women.

Marian MacDorman, a statistician with the National Center for Health Statistics and lead author of the study, says it was a surprise to see such a big increase in a four-year period.

“The number of home births had been declining for a long time,” MacDorman says. From 1989 to 2004, the percentage of home births in the U.S. had been dropping slowly but steadily every year, according to the study.

Still, the number of births at home is pretty small. In 2008, there were 28,357 home births.

Researchers also found a statistically significant improvement in birth outcomes for babies born in the home. Infants who were born preterm fell by 16 percent. The percentage of home births that resulted in infants with a low birth weight also fell by 17 percent.

For the study, which was published in Birth: Issues in Perinatal Care, researchers used data from U.S. birth certificates.

One reason for the better outcomes could be that more women are planning to give birth at home. Researchers found among the 25 states that tracked planning status in 2008, 87 percent of births that occurred at home were planned. MacDorman also suggested that midwives could be getting better at choosing low-risk women to be candidates for home birth.

The safety of home births is a much-debated issue. Last summer, research from the American Journal of Obstetrics and Gynecology found that planned home births were associated with a mortality rate three times as high as babies in hospital deliveries. The Lancet ran an editorial, saying the research “provides the strongest evidence so far that home birth can, after all, be harmful to newborn babies.” But the study methods drew some criticism, and, according to a piece in Nature, the journal re-evaluated but didn’t retract the paper.

Boston University School of Public Health Professor Eugene Declercq, a coauthor of the latest study, told WBUR’s Common Health that previous research had found the top reasons women cited for choosing delivery at home were safety, avoiding unnecessary medical intervetions and a previous bad experience at a hospital.

While home births only account for less than 1 percent of births in the United States, researchers acknowledge that they’re much more prevalent elsewhere in the world. For example, in the Netherlands, 30 percent of births take place at home. But Marian MacDorman says she won’t speculate on whether the increase in the U.S. will continue. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.