The city’s public advocate, Betsy Gotbaum, blasted New York-Presbyterian Weill Cornell Medical Center yesterday for its “alarmingly high” rate of Caesarean sections. More than 37% of births at the hospital in 2003 were by Caesarean section, compared to a citywide average of 26.4%, according to a report Ms. Gotbaum released yesterday.

The hospital’s chief of labor and delivery, Amos Grunebaum, said the public advocate’s criticism is “misleading.” He said that the hospital’s Caesarean-section rate is high because it handles a large number of high-risk pregnancies.

In releasing the report, Ms. Gotbaum said mothers who undergo Caesarean sections are at higher risk for infection, hemorrhaging, organ injury, psychological trauma, and infertility. She cited an estimate from Public Citizen, a watchdog group founded by Ralph Nader, that half of all Caesarean sections performed in America are unnecessary.

The public advocate, who is seeking re-election this year, also said that all 44 hospitals in New York City are shirking their responsibility to disclose data on Caesarean sections to prospective mothers, as required under state law.

Dr. Grunebaum said his hospital makes the data available upon request to all patients.

Speaking to The New York Sun yesterday after a press conference outside Lenox Hill Hospital on the Upper East Side, which had a 31.7% C-section rate in 2003, the most recent year for which statistics are available, Ms. Gotbaum said: “Why would more high-risk women go to New York Hospital than Lenox Hill? I don’t know.”

Dr. Grunebaum said he had called the public advocate’s office yesterday morning at 9 a.m., three hours before Ms. Gotbaum’s noontime press conference, to “educate” her about the factors behind his hospital’s high rates of Caesarean sections.

He said Ms. Gotbaum never returned his phone call.

Dr. Grunebaum told the Sun: “It’s irresponsible to just look at the absolute number without asking ‘Why?’ “

He rattled off three factors that he said accounted for the hospital’s high Caesarean-section rate.

First, he said, approximately 5% of all deliveries at the hospital are multiple births, compared to a national average of 1%. His hospital is home to a world-renowned in vitro fertilization clinic, and in vitro pregnancies are more likely to end in multiple births. An associate professor in the department of internal medicine at the University of Michigan, Steven Bernstein, said the 5% multiple-birth rate at New York Hospital could account for only a small fraction of the disparity between the frequency of Caesarean sections at that hospital and the World Health Organization’s target C-section rate, which is 10% to 15%.

A second factor, according to Dr. Grunebaum, is that his hospital serves an unusually large number of middle-aged mothers.

Third, he said, doctors across the metropolitan region refer complicated cases to his hospital, and these pregnancies are more likely to end in Caesarean deliveries. A medical professor at University of California-Irvine, Bruce Flamm, said: “I doubt that they have a much higher-risk population than New York University and Mount Sinai,” two Manhattan hospitals that are also regional referral centers, and where Caesarean rates hover slightly above 28%.

The director of the maternal fetal medicine and ultrasound division at Washington University in St. Louis, Yoel Sadovsky, said he disagreed with Ms. Gotbaum’s assessment that New York-Presbyterian’s Caesarean-section rate is “alarming.” As a comparison, Dr. Sadovsky said, the Caesarean rate at Washington University’s Barnes-Jewish Hospital in April was also 37%.

New York Hospital is situated on the Upper East Side, and the former chairman of the Task Force on Caesarean Sections at the American College of Obstetricians and Gynecologists, Roger Freeman, said the surgical procedure is becoming particularly commonplace among affluent women.

Dr. Bernstein noted, however, that low-income mothers who have less access to prenatal care might also be at an increased risk for pregnancy complications, and would thus have higher Caesarean-section rates.

Dr. Grunebaum said New York-Presbyterian does not collect socioeconomic data on its obstetrics patients.