A Consumer Reports investigation of more than 1,500 hospitals in 22 states found C-section births for women with low-risk deliveries were as few as 4 percent of births in certain hospitals and as many as 57 percent in others. Low-risk deliveries involve women who haven't had a C-section before, don't deliver prematurely and are pregnant with a single baby who is properly positioned.
Childbirth Connection, a non-profit group, said the best outcomes for women and babies appear to occur with Cesarean section rates of 5 percent to 10 percent and research shows rates higher than 15 percent seem to do more harm than good.
In 1965, the U.S. Cesarean section rate was 4.5 percent but the national C-section rate was 32.8 percent in 2010 and 2011.
"Some C-sections are absolutely necessary for the health mother or baby, but the high rates in some hospitals are "unsupportable by professional guidelines and studies of birth outcomes," said Dr. Elliot Main, director of the California Maternal Quality Care Collaborative and former chairman of the department of obstetrics and gynecology at the California Pacific Medical Center in San Francisco, who reviewed the data of Consumer Reports.
A study published in The Lancet earlier this month found the U.S. infant mortality rate is low, but higher than most other industrialized nations and the U.S. maternal death rate increased slightly from 1990 to 2013.
"C-sections increase the risk of mortality and complications," Dr. Kent Heyborne, chief of obstetrics at Denver Health Medical Center, which had the lowest C-section rate of any hospital in the Consumer Ratings rating, told the magazine.
"But we're just now becoming aware of the down stream effects."
Which hospital a mother chooses to deliver a child can make the difference in what type of birth, but a mother-to-be often has little or no information on which to base a decision.
The Consumer Reports ratings found 66 percent of the hospitals earned the lowest or second-lowest score, while only 12 percent got either of the publication's top two ratings.
C-sections can be lifesaving when the the womb is blocked by the placenta or the baby isn't properly positioned for birth, but the C-section -- the second most commonly performed surgical procedure in the country -- is major surgery and has the risk of major surgery.
Compared with women with vaginal births, healthy, low-risk women undergoing their first C-section were three times more likely to suffer complications such as severe bleeding, blood clots, heart attack, kidney failure and major infections, a 14-year analysis of more than 2 million women in Canada found in 2007.