The most common U.S. hospital procedure is the Caesarean section, with 1.2 million of the operations done each year, according to a government report issued on Tuesday.

Caesarean sections cost $14.6 billion in total charges in 2003, the report from the Agency for Healthcare Research and Quality’s Healthcare Cost and Utilization Project found.

The report, which can be found on the Internet at http://www.hcup.ahrq.gov/, lists the other top five inpatient hospital procedures:

- Upper gastrointestinal endoscopy to diagnose ulcers, stomach cancer and other problems, with 712,000 procedures and $14.5 billion in total charges.

- Catheterization to diagnose heart problems, with 707,000 procedures and $17.3 billion in total charges.

- Respiratory intubation and mechanical ventilation, with 617,000 procedures and $35.4 billion in total charges.

- Angioplasty  to widen narrowed arteries, with 676,000 procedures and $26.5 billion in total charges.

Anne Elixhauser, an analyst who helped compile the report, said she was initially surprised to learn how common Caesarean sections are. But it makes sense given the number of births, she said.

“There are 4 million babies born every year. Twenty percent or more of them are done by C-section. That is a lot of babies,” Elixhauser said in a telephone interview.

“Nearly a quarter of all (U.S) hospital stays are related to pregnancy and childbirth. Most people don’t realize what a big chunk of hospital care that is.”

Elixhauser said the report, based on data from 38 states representing 90 percent of all hospital stays, is weighted to reflect the total U.S. population.

She said the relative ranking of the five procedures does not vary much from year to year.