Recent Empirical Research Suggests Rise in Cesarean Section Rates Not Caused by Malpractice Liability Pressure

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In my recent post on the NIH’s consensus development conference on vaginal birth after cesarean, I noted that one of the recommendations coming out of the conference was that “medico-legal” reforms “be developed, implemented, and evaluated” to determine their effect on cesarean section rates.  Recent empirical research indicates that such reforms are likely to have little impact.

Prior work suggested that medico-legal reforms could play a significant, if supporting, role in efforts to reduce the number of unnecessary cesarean sections.  For example, the authors of a 2006 study published in Health Affairs analyzed the disturbingly large disparities in cesarean rates from county to county and concluded that, for normal weight births, 14.5 percent of the variance in rates was attributable to variance in malpractice premiums and the number and size of malpractice payouts.  Another study published in the journal Medical Care in 2009 found, among other things, a small negative association between cesarean section rates and two types of tort reforms — caps on noneconomic damages and pre-trial screening panels.

In an article in the latest volume of American Law and Economics Review, Influence and Deterrence: How Obstetricians Respond to Litigation Against Themselves and Their Colleagues, Northwestern University researchers David Dranove and Yasutora Watanabe move beyond “macro measures of the malpractice environment” and “tak[e] a micro look at the data, examining on a quarterly basis how physicians respond to claims lodged against themselves and their immediate colleagues.”  Using two rich data sets from Florida, one of all hospital births between 1994-2000 and another of every resolved malpractice claim from that state from 1979-2003, Dranove and Watanabe generate answers to three provocative questions:  Do obstetricians perform proportionally more cesarean sections after they have been sued?  Do their cesarean section rates increase in the wake of suits against other obstetricians at their hospital?  What about when the number of lawsuits filed against non-obstetricians in their county goes up?  The answer to the first two questions is yes, but the “effects are both small in magnitude and very short-lived.”  Moreover, the effect disappears after an obstetrician has been sued once; subsequent suits have no effect.  The answer to the third question is no.

Dranove and Watanabe theorize that “[t]he fact that [the effect of a physician's own history] is short-lived and limited to obstetricians with no previous contacts may indicate that obstetricians overreact to their first contact.  It is possible, for example, that they rapidly discover that the litigation process is neither costly nor particularly painful.  For example, physicians rarely make a financial payment to the plaintiff and do not appear to lose any income as a result of being sued (Danzon et al. 1990; Zeiler et al., 2008).”  They conclude that “[w]hatever has caused the pronounced upswing in [c]esareans, it is not due to the influence of individual, hospital-wide, or regional contacts with the legal system.”  This, of course, causes one to wonder what has caused the “pronounced upswing;” in a subsequent post, I will look at other possible explanations, including reasons related to health care finance and organization.

NIH Panel Recommends Medico-Legal Reform to Reduce Elective Repeat Cesarean Delivery Rate

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In December 2009, an Arizona woman made the news when, in her ninth month of pregnancy, she left her husband and three sons behind and traveled to Phoenix, six hours away from her home, to await the birth of her fourth child.  She took these drastic measures because she wanted to give birth vaginally but her local hospital did not allow women who have had a cesarean section to attempt a vaginal delivery.

Last week, the NIH held a consensus development conference on vaginal birth after cesarean (”VBAC”) to evaluate, among other things, the sharp increase in elective repeat cesarean deliveries in the United States and the medical and non-medical factors that have caused it.  The panel convened by the NIH found that both a trial of labor in women who have had a prior cesarean and an elective repeat cesarean delivery have “important risks and benefits” that “differ for the woman and her fetus.”  A trial of labor is associated with a statistically significant increase in risk of uterine rupture and in risk of perinatal death.  Elective repeat cesarean delivery, on the other hand, is associated with a statistically significant increase in risk of maternal death.  Moreover, as the number of prior cesareans goes up, the risk of serious harm to both mother and baby does too, which is of particular concern to women who hope to have large families.  As the panel notes, these facts and figures pose “a profound ethical dilemma for the woman as well as her caregivers, because benefit for the woman may come at the price of increased risk for the fetus and vice versa.”

The panel concluded that for certain women — those with a “prior low transverse uterine incision” — a trial of labor is a reasonable choice, albeit one that it increasingly constrained by difficulty accessing clinicians and facilities able and willing to offer it. Among the non-medical barriers to VBAC is a recommendation made by the American College of Obstetricians and Gynecologists and the American Society of Anesthesiologists that women with a prior cesarean not be permitted to attempt a vaginal delivery unless the hospital has “immediately available” surgical and anesthesia personnel.  The panel concluded that this recommendation should be reassessed in light of “other obstetrical complications of comparable risk, risk stratification, and in light of limited physician and nursing resources.”

The panel also found that “medico-legal considerations add to, as well as exacerbate” barriers to VBAC.  Midwife Amy Romano, who writes the Science & Sensibility blog for Lamaze International, explains that because “lawsuits focus entirely on the counseling around [uterine] rupture rates, and doctors are sued if that counseling isn’t done or documented effectively, then the doctor has a financial incentive to focus on rupture likelihood[.]“  This steers women toward elective repeat cesarean delivery and exacerbates the already formidable liability barrier to VBAC.  The panel predicted that “caps on noneconomic damages and reductions in physician malpractice premiums would result in fewer cesarean deliveries” and recommended that these and other interventions to reduce the liability barrier be developed, implemented, and evaluated to determine their efficacy.