LONDON — Prince William’s wife, Kate, cast aside British tradition when she picked the team that helped her deliver her baby on Monday.

Instead of turning to a midwife, an option favored by a majority of women in the U.K. as well as Queen Elizabeth II, the Duchess of Cambridge followed the U.S. practice of having doctors on hand for the birth of the boy who will be third in line to the British throne.

The royal birth was supervised by Marcus Setchell, who serves as the queen’s gynecologist, and Guy Thorpe-Beeston, an obstetrician who practices at St. Mary’s Hospital in Paddington, central London, where Kate’s son, weighing 8 pounds, 6 ounces was born Monday.

Kate, the first woman from outside royalty or the aristocracy to marry so close to the throne for 350 years, probably picked what seemed like the safest approach for the high-profile birth of her first child, said Nancy Chescheir, an obstetrician at the University of North Carolina’s School of Medicine in Chapel Hill. Yet scientific evidence suggests a hospital delivery under the care of an obstetrician isn’t necessarily best for routine births.

A 2008 Cochrane Collaboration review found women who used midwives have fewer interventions such as caesarean sections and episiotomies to widen the vagina during delivery, said Holly Powell Kennedy, a midwife and professor at Yale University’s School of Nursing.

“We are all baffled as to why Kate is having an obstetrician,” Sheena Byrom, a midwife based near Preston in northern England, said in an interview before the birth. “It’s not like America.”

The Duchess of Cambridge’s decision has hit a nerve in a country where almost two-thirds of births are supervised by midwives. Queen Elizabeth II delivered her four children at home with midwives, according to Louise Silverton, director of midwifery at the Royal College of Midwives.

“It’s a cultural thing,” Silverton said. “I don’t wait for doctors to tell me what to do, I make my own decisions.”

Midwives focus on high-touch, low-tech deliveries that can yield better results at a lower cost for healthy women, particularly because they’re less likely to use unnecessary medical equipment, said Angela Ferrari, a certified nurse midwife from Massachusetts General Hospital in Boston.

The role of midwives is so established in the country that it’s inspired the popular British Broadcasting Corp. television series entitled “Call the Midwife.” Obstetricians tend to step in for high-risk pregnancies or when complications develop.

In the U.S., the system for prenatal care and delivery is based on the mother’s preference for a midwife or an obstetrician, according to the University of North Carolina’s Chescheir. Certified nurse midwives, the primary type of midwife in the U.S., care only for low-risk pregnancies and are supervised by an obstetrician.

Chescheir, herself an expert in complex, high-risk deliveries, is a fan of midwives, who she says tend to be more holistic, foster less of a medical environment and create a family event. Midwives delivered almost 12 percent of the 2.65 million infants born vaginally in 2011 in the U.S., the most recent statistics available, according to the National Center for Health Statistics.

“I don’t think British women should feel they are being slighted as long as they have access to obstetrical specialists if a problem arises,” said Meg Berreth, a midwife and instructor at the University of North Carolina in Chapel Hill. “A very brief perusal of literature would show you the average woman is getting exceptional, if not better care, with a midwife in the U.S. and Britain.”

Women can also get epidurals and pain medicine even if they are delivering with a midwife, according to Berreth.

“I don’t envy Kate Middleton,” she said, referring to the Duchess of Cambridge by her maiden name. “Every decision she makes becomes a statement.”

Some experts said it made sense for Kate to rely on an obstetrician, given the high-profile pregnancy and its accompanying stress, and risks that can quickly spiral out of control if a delivery starts to go wrong.

“I don’t like to think of one birth being any more important than another’s, but the stakes are extraordinarily high in this case,” Chescheir said. “When there is that much pressure on, it probably makes sense to have a lot of people on board. In obstetrics, when things go bad, they can go bad extraordinarily quickly.”

In the end, Kate made a personal decision choosing obstetricians over midwives, just as her late mother-in-law, Diana, did when she delivered both her boys in the same London hospital in the 1980s under doctor supervision.

“It’s very important that women feel safe during labor,” Berreth said. “For some women that means a hospital and for others that means a home.”