After a decline between 1990 and 2004, the percentage of U.S. births that occurred at home increased by 29% between 2004 and 2009, according to a report from the Centers for Disease Control and Prevention.

The report by the CDC's National Center for Health Statistics found that births at home increased from 0.56% of all births in 2004 to 0.72% in 2009.

"Women may prefer a home birth over a hospital birth for a variety of reasons, including a desire for a low-intervention birth in a familiar environment surrounded by family and friends, and cultural or religious concerns," the authors wrote. "Lack of transportation in rural areas and cost factors may also play a role, as home births cost about one-third as much as hospital births."

For non-Hispanic white women, home births increased by 36%, from 0.80% in 2004 to 1.09% in 2009. About one in every 90 births for non-Hispanic white women is now a home birth. The rate is lower among women of other racial or ethnic groups, with non-Hispanic white women accounting for about 90% of the total increase in home births from 2004 to 2009.

Home births are more common among women ages 35 and older, and among women with several previous children. About 20.8% of home births were to women ages 35 and older, compared to 14.2% of hospital births. About half of home births were to women with at least two previous children, compared with 28% of hospital births. And about 84% of home births were to married women, compared with 59% of hospital births.

The percentage of home births was generally higher in the northwestern part of the United States and lower in the southeastern region. The percentage in 2009 varied from a low of 0.2% of births in Louisiana and the District of Columbia to highs of 2.6% in Montana and 2% in Oregon. Other states with home birth rates of 1.5% or higher include Idaho, Pennsylvania, Utah, Vermont, Washington and Wisconsin.

In 2009, 62% of home births were attended by midwives, including 19% by certified nurse midwives and 43% by other midwives (such as certified professional midwives or direct-entry midwives). Among hospital births, only 7% were attended by midwives.

Home births have a lower risk profile than hospital births, according to the report. The percentage of home births that were preterm was 6%, compared with 12% for hospital births. Less than 1% of home births were multiple deliveries, compared with 3.5% of hospital births.

"The lower risk profile of home births suggests that home birth attendants are selecting low-risk women as candidates for home birth," the authors wrote.