WASHINGTON: Premature births of US babies have been climbing since the mid-1990s and the increase is being driven by Caesarean section deliveries, according to a study published on Wednesday.

Dr Alan Fleischman, medical director and senior vice-president of the March of Dimes infant health advocacy group, voiced concern that a sizable portion of these C-section deliveries may be medically unnecessary.

Premature babies are at greater risk for a number of medical and developmental problems such as troubled breathing, bleeding in the brain, birth defects and death. Premature birth is defined as delivery before the 37th week of pregnancy.

Researchers at the US Centres for Disease Control and Prevention and the March of Dimes compared single births not twins or other multiple births, which are at an increased risk for pre-term birth in 1996 and 2004. The rate of premature births rose by about 10 per cent in that period, they said.

The number of premature births rose from 354,997 in 1996 to 414,054 in 2004, the study published in the journal Clinics in Perinatology showed.

“When one looks at the numbers carefully, there was an increase of 60,000 who were pre-term, and 92 per cent of them were by Caesarean section,” Fleischman said.

The increase comes amid an ongoing controversy over whether some doctors are performing C-sections because they fear being sued if they do not and whether some women are opting for medically unnecessary C-sections out of convenience.

A C-section delivery of a baby through a surgical abdominal incision is advised when a vaginal birth is not possible or is unsafe for the mother or child.—Reuters