Tom Davis sits with his children, from left, Matthew, 12, Jacob, 13, and Ethan, 6, in Chatham, Va. Davis lost his wife, Elizabeth, in 2000, after she gave birth to Ethan. U.S. women are dying from childbirth at the highest rate in decades, new government figures show.

Atlanta ? U.S. women are dying from childbirth at the highest rate in decades, new government figures show. Though the risk of death is very small, experts believe increasing maternal obesity and a jump in Caesarean sections are partly to blame.

Some numbers crunchers note that a change in how such deaths are reported also may be a factor.

“Those of us who look at this a lot say it’s probably a little bit of both,” said Dr. Jeffrey King, an obstetrician who led a recent New York state review of maternal deaths.

The U.S. maternal mortality rate rose to 13 deaths per 100,000 live births in 2004, according to statistics released this week by the National Center for Health Statistics.

The rate was 12 per 100,000 live births in 2003 – the first time the maternal death rate rose above 10 since 1977.

To be sure, death from childbirth remains fairly rare in the United States. The death of infants is much more common – the nation’s infant mortality rate was 679 per 100,000 live births in 2004.

Maternal deaths were a much more common tragedy long ago. Nearly one in every 100 live births resulted in a mother’s death as recently as 90 years ago.

But the fact that maternal deaths are rising at all these days is shocking, said Tim Davis, a Virginia man whose wife Elizabeth died after childbirth in 2000.

“The hardest thing to understand is how in this day and age, in a modern hospital with doctors and nurses, that somebody can just die like that,” he said.

Some statisticians note the number of maternal deaths – still fewer than 600 each year – is small. It’s so small that 50 to 100 extra deaths could raise the rate, said Donna Hoyert, a health scientist with the National Center for Health Statistics. The rate is the number of deaths per 100,000 live births.

Some researchers point to the rising C-section rate, now 29 percent of all births – far higher than what public health experts say is appropriate. Like other surgeries, Caesareans come with risks related to anesthesia, infections and blood clots.

Experts also say obesity may be a factor. Heavier women are more prone to diabetes and other complications.