Campaign against the BAC: The Birth After Caesarean Collaborative Research Trial.

Henci Goer
www.HenciGoer.com
Comment on the Australian VBAC Trial
(submitted August 14, 2006)

I have grave concerns that the Patient Information Sheet fails to provide accurate, complete, unbiased information on which to make a decision.

·         The information sheet grossly misrepresents the excess risk of the baby dying as a result of scar rupture. It cites a “very small risk,” which it defines as a risk of between 1 in 150 to 1 in 250 babies. In point of fact, the excess risk in comparison with planned cesarean surgery is 1 in 2500 to 1 in 10,000 (Guise 2004; Landon 2004; Lydon-Rochelle 2001; Mozurkewich 2000; Smith 2002). To put this number in perspective, the excess risk of losing the pregnancy as a result of amniocentesis is 1 in 167 (Seeds 2004). It is worth noting that pregnancy loss due to amniocentesis happens considerably more often than even the inflated mortality rate reported in the Patient Information Sheet, yet no one questions amniocentesis on grounds of safety.

·         No mention is made of the excess harms of accumulating cesarean surgeries. For mothers, these include a growing risk of placenta accreta (the placenta invades the muscular wall of the uterus, sometimes penetrating through it and invading other organs); surgical injury to bladder, ureters, or bowel; ileus (paralyzed bowel); intensive care unit admission; hemorrhage; and hysterectomy (Silver 2006). For babies, these include preterm birth, low birth weight, and serious respiratory problems (Seidman 1994). This omission is critical because a considerable percentage of women having a second child will go on to have further pregnancies, planned or unplanned. In contrast to the risks of accumulating surgeries, once women have a VBAC, they are almost certain to go on having uneventful vaginal births (Landon 2004a; Lieberman 2001; Macones 2005; Rosen 1990; Smith 2004)

·         Failure to provide optimal care during VBAC labors will result in excess complications and cesarean deliveries. This will give the misimpression that planned cesarean is the better option. One wonders what, if any, attention was given to this issue when planning the trial and selecting participating institutions. To cite but two examples: 

o        Many studies show that VBAC rates of 75% are readily achievable in an unselected population, and a study in which independent midwives provided care achieved an 87% rate (Lieberman 2004). Since most complications in the VBAC population will be found in the women who have unplanned cesarean surgeries, lower VBAC rates than the mid 70 percents will result in avoidable complications associated with the excess surgery that will make VBAC appear worse than it is.

o        Many large studies have established that scar rupture rates during VBAC labors can be 5 per 1000 or less, while some studies report double this rate or more. Inappropriate VBAC management can increase the risk of scar rupture and therefore the rate of serious complications that result from scar rupture. For example, a recent large prospective study reported a scar rupture rate of 4 per 1000 in women laboring spontaneously versus 9 per 1000 in women augmented with oxytocin and 10 per 1000 in women being induced with oxytocin (Landon 2004). Likewise, another large study reported a scar rupture rate of 5 per 1000 with spontaneous labor onset, 8 per 1000 in labors induced with oxytocin, and 25 per 1000 in labors induced with prostaglandin (Lydon-Rochelle 2001). In most cases, awaiting spontaneous labor is as safe or safer than induction, and the need for augmenting labor can be greatly reduced with practices and policies that support normal birth.

·         The Patient Information Sheet asserts that there is “minimal reliable evidence” to recommend planned cesarean section or vaginal birth, but we have large observational studies and systematic reviews of those studies comprising in total tens of thousands of women. All have concluded that either choice entails risks. The likelihood that a randomized trial would reach any other conclusion is nil. Moreover, in many analyses, risks of VBAC and likelihood of VBAC have been quantified for subgroups of women with specific factors in their obstetric history or current pregnancy. The money devoted to this trial could have been spent far better looking at how to make VBAC safer and more effective. For example, while suture material and technique is likely to have an effect on scar integrity, I could not find a single randomized controlled trial, much less a systematic review, addressing this issue.

A grave danger of this trial is that its results will be used by physicians who prefer repeat cesarean surgery as a pseudoscientific rationale for denying access to VBAC. This is not an imaginary concern. The now discredited Hannah (2000) breech trial has been used in this fashion, and in the United States, elements of guidelines developed by the American College of Obstetricians and Gynecologists are frequently cited as reason not to allow VBAC despite no evidence to support them. In point of fact, VBAC refusal violates human rights in that it forces women to agree to major surgery as a condition of obtaining medical care. The grounds on which this denial is usually made, the baby’s safety, also violate human rights, which hold that no person should be forced to undergo any invasive procedure, let alone major surgery, in order to benefit a third party. This holds true even when it is certain that the beneficiary will otherwise die, which is far from the case with VBAC.

References

Guise JM, McDonagh MS, Osterweil P, et al. Systematic review of the incidence and consequences of uterine rupture in women with previous caesarean section. BMJ 2004;329(7456):19-25.

Landon MB, Hauth JC, Leveno KJ, et al. Maternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery. N Engl J Med 2004;351(25):2581-9.

Landon M. The MFMU cesarean section registry:  Factors affecting the success of trial of labor following prior cesarean delivery. Am J Obstet Gynecol 2004a;191(6 supp 1):S17.

Lieberman E. Risk factors for uterine rupture during a trial of labor after cesarean. Clin Obstet Gynecol 2001;44(3):609-21.

Lieberman E, Ernst EK, Rooks JP, et al. Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol 2004;104(5 Pt 1):933-42.

Lydon-Rochelle M, Holt VL, Easterling TR, et al. Risk of uterine rupture during labor among women with a prior cesarean delivery. N Engl J Med 2001;345(1):3-8.

Macones GA, Peipert J, Nelson DB, et al. Maternal complications with vaginal birth after cesarean delivery: a multicenter study. Am J Obstet Gynecol 2005;193(5):1656-62.

Mozurkewich EL, Hutton EK. Elective repeat cesarean delivery versus trial of labor: a meta-analysis of the literature from 1989 to 1999. Am J Obstet Gynecol 2000;183(5):1187-97.

Rosen MG, Dickinson JC. Vaginal birth after cesarean: a meta-analysis of indicators for success. Obstet Gynecol 1990;76(5 Pt 1):865-9.

Seeds JW. Diagnostic mid trimester amniocentesis: how safe? Am J Obstet Gynecol 2004;191(2):607-15.

Seidman DS, Paz I, Nadu A, et al. Are multiple cesarean sections safe? Eur J Obstet Gynecol Reprod Biol 1994;57(1):7-12.

Silver RM, Landon MB, Rouse DJ, et al. Maternal morbidity associated with multiple repeat cesarean deliveries. Obstet Gynecol 2006;107(6):1226-32.

Smith GC, Pell JP, Cameron AD, et al. Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies. JAMA 2002;287(20):2684-90.