WASHINGTON – More than 27% of the babies born in America last year were delivered by Caesarean section, a record high for the surgical method that is a controversial subject among both obstetricians and mothers.

Birth rates for teenagers continued their steady decline, but rates increased for women 35 to 44, the government said yesterday.

Nearly 4.1 million births were recorded in the America in 2003, a slight increase over 2002, according to a report from the National Center for Health Statistics, part of the Centers for Disease Control and Prevention.

Roughly 1.13 million, or 27.6%, were Caesarean deliveries, up from 26.1% in 2002. The rate is up by a third since 1996, said the report, which is a preliminary look at American births last year.

A Caesarean section is major abdominal surgery with potentially serious side effects. The report does not distinguish between those that were medically necessary and those that were elective.

There were 70,000 fewer vaginal deliveries following previous Caesareans, known as VBACs, last year than in 2002. Some research has found increased risk in such vaginal deliveries in certain circumstances.

The drop-off in the procedure follows a 1999 change in guidelines from the American College of Obstetricians and Gynecologists that essentially limits VBACs to large, urban hospitals with continually staffed operating rooms, said Eugene Declercq, professor of maternal and child health at the Boston University School of Public Health.

A group opposed to medically unnecessary Caesareans said 300 U.S. hospitals have banned the vaginal deliveries after C-sections in recent years, contributing to the rise in Caesarean deliveries.

“Doctors get sued for the Caesareans they don’t do or don’t do fast enough, not the unnecessary ones,” said president of the International Caesarean Awareness Network, Tonya Jamois. “Hospitals make more money off Caesareans than vaginal births. There is an economic incentive and a lot of defensive medicine going on.”

The OB/GYN organization advocates a case-by-case approach that weighs the risks of both methods of delivery.

One unexplained trend in the annual report is the continued increase in the rate of premature and low birth weight babies even though the teen birth rate dropped, fewer women were smoking while pregnant, and more women were getting timely prenatal care.

The rate of babies born after fewer than 37 weeks of gestation rose slightly to 12.3%, the highest level in the more than 20 years federal officials have tracked the statistic. Those weighing less than 5.5 pounds increased slightly to 7.9% last year, the report said.