The heavy double doors swung open with a clunk, and a short, dark-haired woman walked uncomfortably onto the labor and delivery ward at Tufts Medical Center. Her husband was at her elbow, supporting her and looking concerned. Just then, she groaned, tightened her face, and braced herself against the wall as another contraction began. One week past her due date, the woman appeared to be in active labor. But after a pair of nurses got her into a blue hospital gown and she was examined by the resident physicians, it turned out that her cervix was dilated only 1 centimeter.

I was the obstetrician on hospital duty that Sunday morning, so I introduced myself and learned that the patient, pregnant with her first child, wished to have as few interventions as possible. Respecting her desire, we decided to reevaluate her in a few hours to see how her labor had progressed.

But would she get her wish? Thirty years ago, the caesarean rate in the United States was 17.9 percent; the most recent government figures now put that rate at 32.9 percent. For first-time mothers, the rate is around 26.5 percent. Put another way, the odds were greater than 1 in 4 that this woman would end up not with the natural delivery she wanted, but with a surgical delivery in one of the two operating rooms down the hall.

Every few years, public health officials wring their hands about the high caesarean rate and pledge to do something about it. In 2000, the federal government set a goal of reducing the caesarean rate among first-time moms to 15 percent (from 18 percent in 1998) by 2010. Instead, officials watched it shoot up.

Here in Massachusetts, where the overall rate was 33.7 percent in 2009, the most recent year for which data are available, the Department of Public Health teamed up with the March of Dimes and invited to a meeting in May obstetric leaders from the 47 hospitals in the Commonwealth that deliver babies. In a conference room at the Massachusetts Medical Society building in Waltham, each attendee was given a sealed envelope with his or her hospital's caesarean rate for first-time mothers who were considered low risk (carrying single, head-down, normal-weight babies, delivering at full term after going into labor spontaneously). Dr. Lauren Smith, the health department's medical director, then showed the assembled leaders a slide containing all of the hospitals' rates, but without naming the facilities. Depending on where they delivered, these Massachusetts moms could expect their chance of undergoing a caesarean to range from 10 percent to 35 percent.

Obviously, any woman's chances will vary depending on her individual circumstances - a 40-something mother carrying twins is almost certainly bound for the operating room, while a 29-year-old with two vaginal deliveries behind her probably is not. And a hospital may have a higher than average rate because it caters to high-risk patients, while another may have a low rate because it refers those cases to other centers.

"I don't know what the correct rate is," Dr. David Acker, chief of obstetrics at Brigham and Women's Hospital told participants, "but I can tell you that at some hospitals it's too high, and at others it may be too low."

***

Caesarean section is a delivery done through a surgical incision made in the patient's abdomen and uterus. Most fundamentally, the procedure is done to prevent injury to the baby or the mother. There are many valid reasons why an obstetrician may choose to operate: if the baby is breech; to prevent a too-large baby from becoming "stuck"; if the mother's cervix fails to dilate adequately; to prevent brain damage or death if a fetal heart-rate monitor indicates the baby might become oxygen-starved; if a mother has had a previous caesarean section.
And, of course, some women are electing to have C-sections purely because of personal preference.

However, some caesareans are done for the wrong reasons: a fear of litigation or a doctor's convenience. The surgery typically takes less than 30 minutes to perform, while the labor process can take hours.

Financial incentives, often blamed for much of the rise in health care costs, probably don't influence the caesarean rate significantly. Physicians receive only about 10 percent more for performing a caesarean than they do for vaginal deliveries (approximately $2,500 for the delivery, prenatal, and postnatal care), and although hospitals are paid significantly more for a caesarean, their costs are greater, too, so the net profit (or loss) for the hospital tends to be equal, according to hospital administrative experts.

Whether a high caesarean rate even matters is the subject of much disagreement among obstetricians and public health experts. "I don't have a sense for what the 'right' caesarean rate is," the health department's Smith said, "but any surgery has the potential for complications, and you want to make sure you are doing it for good and reasonable reasons."

While many women feel strongly about how they give birth, some obstetricians seem to shrug. Their priority is a healthy mother holding her healthy newborn. If the process involves a low-risk surgery that preempts a potentially risky labor, that is a small price to pay.

At a recent Las Vegas conference on obstetrical safety, some 125 members of the audience were asked to raise their hand to indicate their personal C-section rate. "Less than 15 percent?" the speaker asked. Two hands in the large auditorium went up. "Fifteen to 30 percent?" Half the hands were up. "More than 30 percent?" The rest. Then the speaker asked the room, "How many of you care?" No one raised a hand, and the room broke out in laughter.

***

These are tough times for Cambridge Hospital, part of the Cambridge Health Alliance, which has been hit hard by reductions in state payments for health services. Still, there is a striking atmosphere of collegiality on this unit where the overall caesarean rate was only 25.9 percent, eighth lowest in the state, according to the health department's report for 2009. (By comparison, my own hospital, Tufts, which handled 1,228 births in 2009, was at 39.4 percent).

A number of factors contribute to the lower than average caesarean rate at Cambridge Hospital, but many stem from the vision of obstetric care implemented by the chief of the department, Dr. Kathleen Harney. Unlike those obstetricians at the conference in Las Vegas, Harney cares about her hospital's caesarean rate and talks to her colleagues about it. "Keeping it low is a priority," Harney says, and every six months she shows each obstetrician on her staff his or her individual caesarean rate and how it compares with colleagues' (the other names are hidden).

Harney's staff - all of the physicians and midwives are employed by the hospital - work according to a schedule and pay structure that doesn't reward one type of delivery or another. The obstetrician responsible for labor and delivery on any given shift has no obligations - no patient checkups, for example - other than to be in the hospital and deliver babies. As a consequence, there is no incentive to accelerate labor or make sure a delivery occurs at a convenient time.

Harney also credits the lower C-section rate to a decision by the hospital to hire a group of physician assistants. Ironically, by making sure that a skilled surgical assistant is always available, Harney and her colleagues are able to give a difficult labor more time to progress before they "call" a caesarean, knowing that they can get the surgery underway fast.

Most critical to the relatively low caesarean rate, in my opinion, is that Cambridge Hospital has a culture of nonintervention. This has some tangible elements: More than half of the 1,317 deliveries in 2009 were done by certified nurse midwives or family physicians. Neither typically performs caesareans and, as professional groups, both have lower caesarean rates than do obstetricians. (If a midwife or family physician is worried about a laboring patient, he or she can consult the on-call obstetrician, who can, if necessary, use forceps or a vacuum to hasten delivery or do a caesarean.) The hospital also supports a birth center dedicated to natural deliveries without anesthesia or interventions (the birth center's vaginal deliveries are not included in Cambridge Hospital's numbers).

Another example of this mind-set is Dr. Jen Retsinas, who worked for the Alaska Native Medical Center in Anchorage before coming to Cambridge Hospital. "I have the lowest C-section rate here," says Retsinas, whose 4.4 percent rate last quarter was atypically low, even for her. Retsinas, who admits that she has a "deep skepticism of traditional medicine," fits in at Cambridge Hospital, but probably wouldn't elsewhere. Her absolute refusal to perform "elective caesareans" - those done on demand without a medical indication - might alienate patients and colleagues at another hospital with a more traditional obstetric culture.

The culture that embraces an obstetrician like Retsinas is self-selecting: It attracts physicians and patients who share and reinforce its values and may repel patients and physicians who don't. It's not monolithic, either; two obstetricians on Harney's staff - she won't name them - have higher than average caesarean rates, and Harney says she doesn't pressure them to change their practice patterns.

***
Several hours after my patient arrived at Tufts, her cervix was still barely dilated. I was faced with a dilemma: Many obstetricians recommend induction - starting labor artificially using medications or other means - one week after the due date passes in order to prevent the small but real risk of stillbirth. However, that unequivocally increases the risk of a caesarean. Many experts fault the rising propensity to induce labor, instead of waiting for it to happen naturally, for the increase in the caesarean rate.

I felt it was time to induce. I explained my reasoning, and my patient and her husband agreed. She would not have her intervention-free labor after all. Then, a few hours later, we ran into another problem: The monitor that tracked the baby's heart rate as a bumpy line on graph paper started to show the occasional drop from a reassuring 135 beats per minute to rates in the 90s. Assuming that the umbilical cord was being squeezed, the nurses administered oxygen through a plastic mask and repositioned the patient's body. The dips stopped, but two hours later, her cervix was still only 5 centimeters dilated.

The truth is, an obstetrician can persuade almost any patient at any time that a caesarean is the best choice. I could have told this woman that the transient dips in the heart rate concerned me and that I recommended surgery to prevent her baby from being harmed. Few patients, hearing those words, would refuse. If I performed a caesarean, I could eliminate the risk that something would go wrong later. In the mind-set of an obstetrician, this is critical.

Obstetricians in Massachusetts pay between approximately $60,000 and $130,000 annually for medical malpractice insurance, primarily because if a baby is injured during labor and the obstetrician is successfully blamed, a multimillion-dollar payment is commonplace. The average obstetrician is sued nearly three times before he or she retires, so the threat of litigation represents a constant pressure. We are rarely blamed for what we do but are often faulted for what we fail to do. As a consequence, when in doubt, many obstetricians reach for the scalpel.
"The biggest downside to doing a caesarean, assuming you don't have complications, is that it costs the [health care] system more," says Dr. Michael Grossman, an obstetrician/gynecologist in private practice in North Andover. "The biggest downside [to not doing a caesarean] is that you lose the kid. It may not affect the statistics, but on an individual basis it's pretty damn important."

The statistical translation of this fear is the rise in the number of caesareans done for "fetal distress" - 20 percent in seven years in a 2011 study published in a leading obstetrics journal. Babies aren't having more "distress"; doctors are just more likely to make this diagnosis and operate because of it. My patient's nurse, two resident physicians, and I discussed her labor. We agreed that the baby was not in immediate jeopardy. Although we considered it, we still didn't recommend a caesarean.

***

Thirty miles up interstate 93 from Cambridge Hospital, Holy Family Hospital in Methuen had the state's fourth-highest overall caesarean rate in 2009 - 40.9 percent. There, practice patterns and the obstetrical culture may help explain the higher than average rate.

Nearly 90 percent of the 1,015 deliveries at Holy Family in 2009 were done by eight obstetricians, five of whom operate their own solo private practices from offices several miles from the hospital. During the day, each doctor is responsible for his or her own laboring patients, which means that a doctor may have an office full of patients scheduled for visits at 15-minute intervals as well as, several miles away at the hospital, one or more pregnant patients in labor. (Several health professionals with close ties to Holy Family were interviewed for this story but did not want their names attached to quotes for fear of possible retaliation.)

If a labor nurse is worried about a patient and summons the patient's doctor, he or she has two options: Race to the hospital to evaluate the patient and, if satisfied with her progress, allow labor to continue, risking the chance that repeated interruptions during the day could create havoc in the office, or tell the nurse to prepare the operating room, explain to the patient in labor why she needs a caesarean, perform the surgery, and be back in the office in an hour, confident that the rest of the day will be uninterrupted.

At night, the obstetricians take turns being on-call for all of the practices' patients. Yet even this system may create an incentive for the doctors to deliver their own patients before signing out for the night: Each pays $500 to the on-call doctor for every delivery.

Another reason high caesarean rates can become self-perpetuating within a population is because once a woman has one C-section, all her future births, for safety reasons, are likely to be the same. Because labor after a caesarean increases the risk that the uterus will rupture at the scar site, potentially causing massive hemorrhage and irreparable injury, the American College of Obstetricians and Gynecologists decreed in 1999 that hospitals providing this service needed to be prepared to do urgent caesareans, including staffing an in-house obstetrician and anesthesiologist. As a result, many community hospitals simply banned the procedure. Vaginal birth after a caesarean (VBAC) rates in the United States, which had peaked at 28.3 percent in 1996, declined to around 8 percent in 2007. Statewide, only 8.7 percent of Massachusetts women had a VBAC in 2009. At Holy Family, the rate was 1.6 percent, because the obstetricians there are reluctant to perform them, they say.

Holy Family's administrators say they do not confer with the obstetricians about the high caesarean rate. "The delivery approach is a decision made between the OB/GYN and their patient, not the hospital," wrote hospital spokeswoman Danielle Perry in an e-mail. Hospital administrators, including CEO Lester Schindel, declined to be interviewed for this story.

A discussion about hiring full-time staff doctors at Holy Family who would care for laboring patients while obstetricians were unavailable foundered when the obstetricians balked at paying part of the cost, according to physicians who vetted the plan.

Dr. Michel Lirette, a beloved French-Canadian transplant, says he typically delivers at least 40 percent of his patients by caesarean, and because he delivers approximately 1 in 6 babies born at Holy Family, influences its higher than average rate. Lirette says that up to 10 percent of his first-time pregnant patients never want to labor and schedule their caesareans. Many of these patients, according to Lirette, seek him out because he respects their choice for a surgical delivery. "My patients are happy with the care they receive, and they come back to me" with subsequent pregnancies, Lirette says. "I make sure they have a good experience and deliver a healthy baby."

"We have to deal with individual patients," says Grossman, who also practices at Holy Family, "whereas pressure from the state and society to keep the C-section rate low are all based on population outcomes. These priorities are 100 percent non-compatible."

***

Some 20 hours after she arrived, my patient's cervix finally became fully dilated. With the next contraction, she pulled her legs back and pushed as hard as she could. But now the baby's heart rate, which had concerned us throughout the labor, dipped again with each push. Research suggests that even the most worrisome heart rate pattern rarely predicts injury. Still, I had to make a decision.

In my gut, I believed that my patient's baby would make it safely to delivery. But I couldn't predict how long it would take: an hour, two? Forceps or a vacuum wasn't an option - the baby's head was still too high up within the pelvis. I'll admit that it crossed my mind that when my shift ended in two hours, my colleague would be annoyed to take over responsibility for a patient pushing that long and with a less-than-perfect heart rate pattern.

I sat down in a chair beside my patient's bed. "I'm not worried about your baby right this minute," I told her. "However, you have a lot of pushing yet to do, and I'm concerned that your baby will not tolerate it. My recommendation is that we do a caesarean now. I think it's the safest thing."

Under bright lights, 20 minutes later, we delivered a little girl, who emerged screaming and pink. My patient and her husband were delighted and thanked me for guiding them to a safe delivery. I didn't spend time second-guessing my decision: Everyone was healthy; the new family was content. None of us mentioned the fact that surgery would now almost certainly be required for the birth of their future children. And it certainly never crossed my mind that my personal C-section rate had just ticked up.

Dr. Adam Wolfberg is a maternal-fetal medicine specialist at Tufts Medical Center and the author of the forthcoming book Fragile Beginnings. He can be reached at adam@adamwolfberg.com. Send comments to magazine@globe.com.