Now a growing number of experts are asking whether it's necessary to do so many.
"This is not the case in other countries that get better results without doing routine pelvic exams," Dr. Carolyn L. Westhoff, a gynecologist at Columbia University Medical Center, said in an interview.
"I'm an American gynecologist, and that's how we were trained. It took many years for me to ask, 'Why are we doing this?' "
For most women, Pap smears are now recommended just once every three to five years — and for some, not at all. No doubt many women would be delighted to skip the routine pelvic exam, too, which many find uncomfortable and embarrassing.
A woman undergoing the exam is bare below the waist. She lies on the examining table on her back with her knees bent and legs spread apart, her feet in stirrups and her buttocks near the end of the table. The doctor inserts a lubricated, gloved finger into her vagina and, with the other hand, presses down on her abdomen to check the shape and size of her uterus and ovaries.
It's called a bimanual exam. Dr. Westhoff is among an increasing number of experts now challenging the value of this time-honored practice, which is done as a matter of course when women come in for routine gynecological checkups or Pap smears.
These experts say that for women who are well, a routine bimanual exam is not supported by medical evidence, increases the costs of medical care and discourages some women, especially adolescents, from seeking needed care.
Moreover, the exam sometimes reveals benign conditions that lead to follow-up procedures, including surgery, that do not improve a woman's health but instead cause anxiety, lost time from work, potential complications and unnecessary costs.
"The number of women who follow this unfortunate path each year is unknown but is likely sizable given the sheer number of pelvic examinations performed each year in the United States," Dr. George F. Sawaya wrote in the Archives of Internal Medicine in December 2011.
"In my experience as a practicing gynecologist, I frequently have had to take patients into the operating room because I found an enlargement during a bimanual pelvic exam," Dr. Sawaya, a professor of obstetrics at the University of California, San Francisco, said in an interview.
"I then follow up with a sonogram which shows a mass, but I can't tell what the mass is without surgical exploration. Yet nearly always it's benign."
Dr. Sawaya says it's time to change this practice, in which doctors "put patients in a perilous situation and then act like they're rescuing them." He admits that his position "won't win any popularity contests, but I'm trying to do what's right for patients."
Dr. Westhoff and colleagues wrote in January 2011 in The Journal of Women's Health, "Frequent routine bimanual examinations may partly explain why U.S. rates of ovarian cystectomy andhysterectomy are more than twice as high as rates in European countries, where the use of the pelvic examination is limited to symptomatic women."
She and others say that the justifications gynecologists typically offer for doing the pelvic exam — screening for a sexually transmitted infection and cervical cancer, early detection of ovarian cancer, and evaluating a woman for hormonal contraception — either do not require a bimanual exam or are not supported by research.
In a multicenter trial supported by the National Cancer Institute, for instance, no cancers of the ovaries were detected by a pelvic examination alone. The test sometimes did produce suspicious findings that resulted in further procedures.
"The pelvic examination is not an effective screening tool for ovarian cancer," Ms. Analia Stormo, a researcher at the Centers for Disease Control and Prevention, and colleagues wrote last March in the journal Preventive Medicine.
Yet Ms. Stormo also found that "almost 70 percent of obstetrician-gynecologists reported believing that a pelvic examination is an effective means of screening for ovarian cancer."
To screen for sexually transmitted Chlamydia and gonorrhea, tests done on a urine sample or vaginal swab obtained by the patient "have numerous advantages" over the pelvic exam, Ms. Stormo and colleagues noted.
Although a pelvic exam has been traditionally coupled with prescriptions for contraception, both the American College of Obstetricians and Gynecologists and the World Health Organization have said that hormonal contraceptives like the birth control pill can be prescribed without first doing a pelvic exam.
"Whenever doctors are doing things by rote, we have to rethink whether what they're doing is really helpful," Dr. Sawaya said.
Dr. Westhoff concurs: "We should limit the well-woman checkup to proven procedures."
That is likely to be an uphill battle. Recent surveys by Dr. Sawaya and colleagues, among others, have shown that most gynecologists in the United States consider the routine bimanual exam of internal reproductive organs an important part of a well-woman visit. The practice is endorsed by the American College of Obstetricians and Gynecologists, which nonetheless admits that medical evidence to justify it is lacking.
In the latest study, published online in November in the college's journal, Jillian T. Henderson, an assistant professor of obstetrics at the University of California, San Francisco, Dr. Sawaya and colleagues examined the circumstances under which a national sample of obstetrician-gynecologists would conduct a bimanual pelvic exam. The doctors were presented four vignettes about healthy patients, ages 18, 35, 55 and 70, who come "for a routine health visit."
Nearly all 250 doctors who took the survey said they "would conduct bimanual pelvic examinations in routine visits with asymptomatic women across the life span," even in a 55-year-old woman described as having no ovaries, uterus or cervix.
Most of the clinicians surveyed said the exam was important to identify benign uterine fibroids, even though the value of this finding in women lacking symptoms is unclear, the team reported. Most clinicians also maintained that the pelvic exam was important "to reassure patients of their health."
How important is this exam to a doctor's income? Slightly more than half of those surveyed ranked "ensuring adequate compensation" as very important or moderately important.
One of the most vexing problems in medicine today is the fact that doctors get paid only for performing procedures, not for the time they spend talking with patients to discuss issues of possible medical importance.
The next time you see your gynecologist for a routine checkup, ask if a pelvic exam is planned and, if so, what the doctor expects it to accomplish.