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COPYRIGHT 2002 Mothering Magazine
The July 5, 2001, issue of the New England Journal of Medicine contained a study by Mona Lydon-Rochelle et al. (1) and an accompanying editorial by Michael E Greene, MD, (2) which together generated much media attention and discussion of the risks of vaginal birth after cesarean (VBAC). the study actually contains little new or ground-information and relies on questionable data collection, media-and even some physicians--are claiming a greater risk for uterine rupture than previous shown. Headlines across the nation have suggested that research now supports repeat cesarean section over VBAC, number of physicians have opined that cesarean safe or safer than vaginal birth.
But take a closer look: what physicians are inadvertently that their overuse of medical intervention in childbirth has succeeded in making the average vaginal birth as risky as major surgery. A careful critique exposes the limitations of and the current medical model of childbirth, question of whether that model still holds any credibility for pregnant women.
Study Results
The study used Washington State birth certificate data in combination with hospital discharge data from the years 1987 to 1996 to examine the incidence of uterine rupture in four groups of women: those who had an elective repeat cesarean section (ERCS) without labor (n=6,980), those who attempted VBAC with spontaneous onset of labor (n=10,789), those who had labor induced by non-prostaglandin methods (n=1,960), and those whose labor induction included prostaglandins (n=366). The uterine rupture rate for women having a scheduled elective repeat cesarean was 0.16 percent, or 11/6,980. For women with spontaneous onset of labor (SOOL), the rate was 0.54 percent (56/10,789); with non-prostaglandin induction, the rate was 0.77 percent (15/1,960); and for women with induction which involved prostaglandins the rate was 2.45 percent (9/366).
None of these rates is significantly different from those found in previous studies. In fact, the rate of rupture among women having a trial of labor was lower than many recent studies have suggested. The rate for all women attempting VBAC was 0.6 percent, which falls on the low end of the 0.2 to 1.5 percent range cited by the American College of Obstetricians and Gynecologists (ACOG) in a review of the literature for their VBAC practice guidelines. (3) Rates of 0.5 to 1.0 percent have been used in the past as evidence for the relative safety of VBAC; those who are using those same rates now to suggest that VBAC is too risky are engaging in an egregious display of statistical sleight of hand for the purpose of limiting women's access to VBAC. The motivations that are behind this movement are discussed in the conclusions of this article.
IT IS CERTAINLY NOT NEWSWORTHY TO find that elective repeat cesarean does not completely protect a woman from the risk of rupture. It is the prior cesarean, not VBAC, that exposes mother and baby to the risk of uterine rupture. A prior cesarean scar also predisposes the mother and baby to other obstetrical complications that are rarely seen in women with intact uteri. Physicians know well that cesareans cast a long shadow over the rest of a woman's reproductive life, one that can affect both her and her unborn children's health and safety. Yet the cesarean rate reached 22.9 percent in 2000, an 11 percent increase over the previous four years and the highest rate reported since 1989. (4) Clearly, physicians are not doing enough to reduce the number of unnecessary cesareans (conservatively estimated at 50 percent of all cesareans, or approximately 500,000 per year). (5) Therefore, they must bear the responsibility for the complications that their often cavalier use of surgical intervention continues to cause; proposing further surgery as a solution will only compound the problem.
The most notable finding of the New England Journal of Medicine study--and one that has barely made a ripple in the news media--is the dramatic increase in risk of rupture seen with induction of labor that includes the use of prostaglandins. Although previous studies have linked powerful synthetic hormones used to induce labor with an increased risk of rupture, this study attempted to isolate the use of prostaglandins as a distinctly separate risk factor and expressed it in terms of relative risk with respect to elective repeat cesarean. The rate of rupture among women induced with prostaglandins was 15 times higher than that of women who didn't labor at all. When compared to the risk of rupture for women who entered labor spontaneously, the rupture rate with prostaglandin induction was nearly five times higher. This should give caregivers and expectant women pause before they consider induction of labor after a previous surgical delivery, which is alarmingly common today.
Uterine rupture is a serious, life-threatening complication for both mother and baby. As Michael F. Greene observed in his editorial, Lydon-Rochelle et al. found that when uterine rupture occurred the odds of the baby dying were 5.5 percent. The odds of a baby dying in the absence of uterine rupture were 0.5 percent. Greene states that this is a tenfold increase in the risk of fetal death, which although statistically valid is a gross misrepresentation. Of the 91 total ruptures recorded in the study, there were five fetal deaths. (The authors did not indicate in which of the study groups these deaths were found because the sample was too small to draw any valid conclusions.) Those five deaths represent a 5.5 percent fetal mortality rate in the subset of women who had a uterine rupture (n=91). Note that the data did not allow the researchers to conclude that the ruptures necessarily caused the deaths, merely that they were associated with rupture.
In the non-uterine rupture group (n=20,004), there were 100 fetal deaths, for a fetal mortality rate of 0.5 percent. Although that can be expressed as a tenfold increase in the death rate for uterine rupture versus non-uterine rupture, to do so...
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