U.S. maternal death rate has risen, but why?

ATLANTA — U.S. women are dying from childbirth at the highest rate in decades, new government figures show. Though the risk of death is small, experts think an increase in maternal obesity and a jump in Caesarean sections are partly to blame.

Some number-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.

Death from childbirth remains 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.

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 health statisticians note the total number of maternal deaths — 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 scientist with the National Center for Health Statistics. The rate is the number of deaths per 100,000 live births.

In 2003, there was a change in death-certificate questions in the nation's most populous state, California, and Montana and Idaho. That may have resulted in more deaths being linked to childbirth, enough push up the 2003 rate, Hoyert said.

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

"There's an inherent risk to C-sections," said Dr. Elliott Main, who co-chairs a panel reviewing obstetrics care in California. "As you do thousands and thousands of them, there's going to be a price."

Excessive bleeding is one of the leading causes of pregnancy-related death, and women with several previous C-sections are at especially high risk, according to a review of maternal deaths in New York. Blood-vessel blockages and infections are among the other leading causes.

Experts also say obesity may be a factor. Heavier women are more prone to diabetes and other complications, and they may have excess tissue and larger babies that make a vaginal delivery more problematic. That can lead to more C-sections. "It becomes this sort of snowball effect," said King, now medical director of maternal-fetal medicine at Riverside Methodist Hospital in Columbus, Ohio.

The age of mothers could be a factor, too. More women are giving birth in their late 30s and 40s, when complications risks are greater.

Race is also a factor in maternal deaths. Studies have found that the maternal death rate in black women is at least three times greater than it is for whites. Black women are more susceptible to complications such as high blood pressure and are more likely to get inadequate prenatal care.