The last few months have proved fertile ground for newsworthy reports of universal interest concerning the health of pregnant women and newborns, the likely overuse of C-sections, and the role of hospitals and health care providers in shaping parental decisions about childbirth.

Beginning with a report from the Centers for Disease Control and Prevention, we learned last December that nearly 1 in 3 women giving birth in the U.S. did so by cesarean section. That whopping rate dramatically exceeded the World Health Organization's recommended upper limit of 10 to 15 percent.

This month, we subsequently learned about wild variations in cesarean rates within our own country. After analyzing data from 1,500-plus hospitals in 22 states, Consumer Reports documented C-section rates that ranged between 4 and 57 percent among comparable groups of pregnant women. For two hospitals, mere miles away, rates were 55 versus 15 percent.

Why such profound variations? Should our standards of medical practice be so flexible?

The answer is "complicated" replies Dr. Kirsten Salmeen of the Maternal Fetal Medicine Division at UC San Francisco. She thinks variations in cesarean rates across the country are "likely due to a combination of factors." That includes differences in patient populations and preferences, provider availability and coverage, hospital and provider culture, access to anesthesia and surgical obstetric services, and the prevailing medico-legal climate.

For example, Salmeen proposed that a difference in rate might depend upon the scope of available obstetrical services. In a hospital staffed with 24/7 obstetric coverage and resourced to provide a C-section when needed, a woman might be allowed more time for labor with a vaginal delivery. In contrast, that may not be as feasible with a solo or small-group provider who'd have to cancel scheduled clinic appointments with many patients in order to wait upon one patient's labor.

Professional societies like the American College of Obstetricians and Gynecologists, or ACOG, have long been troubled by our variable and relatively high cesarean rates. In 2010, ACOG resoundingly discouraged the widespread practice of routinely repeating C-sections for most women who'd undergone a prior cesarean delivery.

In March, ACOG also updated its obstetric practice guidelines, hoping, more generally, to decrease medically unnecessary cesareans. The guidelines acknowledged that the observed "increase in the cesarean delivery rate or its regional variations" couldn't be fully explained by "maternal factors" -- that is, by the rote medical facts associated with a pregnant woman's condition. Rather, "other potentially modifiable factors" were in play, including arbitrary limitations on the time allowed women to progress in labor to vaginal delivery before surgical intervention was introduced.

Medically unnecessary C-sections are problematic on multiple fronts, primarily because of the undue risks they impose on women during childbirth. C-sections -- as major surgical procedures involving deep incisions through a woman's abdomen and uterus -- introduce anesthetic and operative risks that include infection, hemorrhage, scarring, adhesions, surgical trauma to nearby organs, longer recovery times and higher mortality.

In addition, some critics allege that financial incentives may be driving cesarean surgery rates. Indeed, compared to vaginal births, cesarean births generate substantially greater payments to hospitals from private insurance and Medicaid.

Meanwhile, it's sobering to note that we've not witnessed steady improvements in health outcomes for pregnant women and newborns.

As ACOG summarized in March, the increase in cesarean birthrates "without clear evidence of concomitant decreases in maternal or neonatal morbidity or mortality raises significant concern that cesarean delivery is overused."

A study this month in The Lancet actually revealed that our maternal mortality rates increased slightly between 1990 and 2013. Researchers characterized that drift as "a deviation from the general trend downwards in developed countries." They also found that our infant mortality rate was higher than most industrialized nations, including Saudi Arabia and Canada.

Salmeen suggests that we can't be certain about the causes for our relatively high maternal mortality rates, but they're bound to be multifactorial. Comprehensive accounting would likely reflect influences like advanced maternal age, high burdens of chronic disease and lack of health care access -- all associated with higher maternal mortality risk. She notes that older women, transplant recipients, and women with heart diseases and significant health problems are now routinely conceiving within the U.S.

Clearly, we need to look more closely at our American way of childbirth to understand what we should be doing to make it as safe as possible for pregnant women and their babies. And we have to concede that while C-sections have saved lives, they're too often used without medical justification, imposing unnecessary risks on healthy women and babies.

In the meantime, what should a pregnant woman do to minimize her risk of having a medically unnecessary C-section? Salmeen recommends that, beyond maintaining a healthy lifestyle, she should establish a good relationship with a health care provider early in her pregnancy. That provider should be someone who demonstrates "a commitment to vaginal birth" -- both generally and as an option for women with a history of a prior cesarean.

"At the end of the day," she concludes, "establishing a trusting relationship with a provider who has an 'only as needed' philosophy regarding cesareans is likely the best strategy."

Kate Scannell is a Bay Area physician and the author, most recently, of "Flood Stage."