VBAC Risks and Benefits: A Review of the Evidence

1. VBAC Risks and Benefits: A Review of the Evidence American College of Nurse Midwifery 2005 Washington, D.C. “Hot Topics” Betty-Anne Daviss, MA, RM Adjunct Professor, Pauline Jewett Institute of Women’s Studies, Carleton University & Kenneth C. Johnson, PhD Centre for Chronic Disease Prevention and Control Public Health Agency of Canada

2. Overview of NACC Study Repercussions • NACC study example of a trend in the use of single studies to drive practice • Implications for the way “science” is used • Repercussions for American women on choice • Repercussions internationally on women’s choice in VBAC

3. Disturbing Trends • Single studies given more merit than warranted, often ignoring systematic reviews • 1. Hannah, The Term Breech Trial (2000) • 2. Pang et al. Washington Home Birth Study (2002) • 3. Lydon Rochelle et al., NEJM VBAC study (2001) • 4. Lieberman et. al, NACC VBAC Study(2004)

4. Similarities in the Response to The Single Studies 1. Studies adopted to practice in isolation of former studies. 2. Adoption of intervention occurred largely because of editorials and high profile granted to the studies, regardless of merit. 3. Adoption almost immediate, prompted by hospital meetings, obstetric association directives, and mass media.

5. Similarities in the Response to These Single Studies • 4. Evidence of flaws in the studies or unwarranted conclusions were not published for several months, by which time practice was already changed, and reversal of the decision not implemented. • 5. Lack of inter-disciplinary or consumer/ professional forums to discuss larger implications of change of practice. • 6. Adoption of each study increased intervention.

6. Meta-analyses Recommendations Ignored Rosen, Dickinson and Westhoff. • Vaginal Birth after cesarean: a meta-analysis of morbidity and mortality. Obstet Gynecol. March 1991 Roberts et al. Trial of Labor or Repeated Cesarean Section Arch Fam Med Mar/Apr 1997 Mozurkewich and Hutton. • Elective Repeat Cesarean Delivery vs. Trial of Labor:Ameta-analysis of the literature from 1989 to 1999 Am J Obstet Gynecol Nov 2000

7. Meta-analyses Recommendations • 1. Rosen, Dickinson and Westhoff: • VBAC appears to be a safe component of obstetric care, and failed VBAC with consequent cesarean poses no major risks. • Need to modify Cragin’s original dictum to “Once a cesarean, a trial of labour should precede a second cesarean except in the most unusual circumstances.”

8. Meta-analyses Recommendations • 2. Roberts R, Bell H, Wall E, Moy J, Hess G, Bower H • In balancing the potentially competing values of patient preferences vs cost containment, we concluded that clinicians should counsel women about the risks, benefits, and costs of TOL and ERCS, and a guideline should recommend TOL, but respect a woman’s preference for ERCS.

9. Meta-analyses Recommendations • 3. Mozurkewich and Hutton. • Small increases in the uterine rupture rate and in fetal and neonatal mortality rates may result from a trial of labor compared to elective repeat cesarean section. • These increases may be counterbalanced by reductions in maternal morbidity with a trial of labor, including febrile morbidity, transfusion, and hysterectomy. • Either a trial of labor or elective repeat cesarean delivery may be a reasonable option for women with at least one previous cesarean delivery.

10. Single study adopted Lydon-Rochelle et al. Risk of uterine rupture during labor among women with a prior cesarean delivery NEJM 2001

11. Risk of Uterine Rupture During Labor among VBACs (Lydon-Rochelle) • For women with one prior cesarean delivery, the risk of uterine rupture is higher among those whose labor is induced than among those with repeated cesarean delivery without labour. Labour induced with a prostaglandin confers the highest risk.

12. How the Study Was Used • NEJM Editorial extrapolated recommendations not contained in the study • Rather than commentary being we shouldn’t do induction with VBACs, we shouldn’t do VBACs • ACOG made use of the study at a press conference to announce to the media the increased dangers of VBAC

13. Repercussions of the Lydon-Rochelle Study • All former meta-analyses ignored • Changed practice within a couple of months • Response in letters to the editor of the NEJM and the BMJ not published for six months

14. % VBAC Low Risk* Mothers, U.S., 1990-2001 * Full-gestation(37+ weeks), vertex presentation, singleton births

15. Current Changes:National Cesarean Rates 1990-2002

16. VBAC deliveries - USA 1989-2003

17. National Study of Vaginal Birth After Cesarean in Birth Centers (NACC Study) • Prospective study of 1453 attempted VBACs in 41 U.S. Birth Centers – 1990-2000 • 24% transfer to hospital • 87% VBAC success

18. NACC Study Uterine Rupture

19. NACC Study Perinatal Death

20. NACC Study Conclusions “Despite a high rate of vaginal births and few uterine ruptures among women attempting VBACs in birth centers, a caesarean-scarred uterus was associated with increases in complications that require hospital management. Therefore, birth centers should refer women who have undergone previous cesarean deliveries to hospitals for delivery. Hospitals should increase access to in-hospital care provided by midwife/obstetrician teams during VBACs.”

21. Using the same logic: • Because women of lower socio-economic status have higher risk of perinatal death, • they should all go to the best tertiary care hospitals.

22. Using Similar Logic: • Landon MB et al. found: • 7 maternal deaths in 15, 801 elective cesareans • 3 maternal deaths in 17, 898 attempted VBACs • We could therefore conclude that elective caesarean section should not be done in academic institutions

23. Alternative Conclusions Because in this study there was a high rate of vaginal births and few uterine ruptures among women attempting VBACs in birth centers, And because the perinatal mortality of 2 per thousand in those with a single former caesarean section is very low (consider the overall perinatal mortality in the USA)

24. Alternative Conclusions therefore, reflection for those planning VBACS in out of hospital births should be more cautious if they have had two former caesarean sections or are >=42 weeks. Women should also be told about the risk of cesareans along with the risks of VBACs and ruptures (Cesarean risks include increased odds of infertility, miscarriage, ectopic pregnancy, placenta abruption, praevia and accreta, respiratory problems including persistent pulmonary hypertension)

25. WHO: Beyond the Numbers “Knowing the level of maternal mortality is not enough; we need to understand the underlying factors that led to the deaths. • “Each maternal death or case of life-threatening complications has a story to tell and can provide indications on practical ways of addressing the problem.” • Perinatal Audits

26. Considerations • Individual Audit • Responsibilities when publishing the numbers • Without giving context and precautions about how “the numbers” will be used

27. Implications • Implications for the way “science” is used • Repercussions for American women on choice • Repercussions internationally on women’s choice in VBAC

28. Repercussions Internationally • ACNM VBAC protocols – out-of-hospital setting • Are American standards based on research? • Reconsider what access to “immediate” caesarean section means

29. Society of Obstetricians and Gynaecologists of Canada • The word “timely” has replaced “immediate.” • 30 minutes is timely enough

30. Conclusions • Choice of birth place is multi-factorial, based on science, liability, culture • Evaluate where risks are to inform women and caregivers

32. References • 1. Lieberman E, et al. Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol. 2004;104:933-42. •  2. Maternity Center Association. What Every Pregnant Woman Needs to Know About Cesarean Section. New York: MCA, 2004. •  3. Landon MB. et al. Maternal and perinatal outcomes associated with a trial of labour after prior cesarean delivery. NEJM. 2004;351(25);2581-89. • 4. Johnson KC and Daviss BA. Re:Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol. 2005 in Press April 2005.

33. Letters to the editor re Lydon-Rochelle in BMJ December 2001 • Daviss BA • 1. Study’s focus on induction v spontaneous labour neglects spontaneous delivery (Study did not provide comparison group of women with no intervention because did not stratify for oxytocic use) • Johnson K, Gaskin I • 2. Safety of single-layer suturing in caesarean sections must be proven (the apparent increase in TOL rupture rates in the 1990’s may have been caused by a change to single layer suturing of the uterine incision – not evidence based)

34. Letters to the Editor re Lydon Rochelle in NEJM Jan 2002 • Heffner, L. Brigham and Women’s hospital • 3. Study doesn’t provide incremental risks (absolute risks) of perinatal mortality with each category of delivery, only the relative risk of infant death should rupture occur • Incremental Risk: • Csect: 0.09 deaths per 1000 • Spontaneous Labour: 0.28 deaths per 1000 • VBAC Induction: 0.47 deaths per 1000 • 2% increase in perinatal mortality from 5.2 to 5.4 per 1000 births • Bottom Line: Study suggests non-induced VBAC may result in less than 1 excess death per 5,000 births

35. Letters to the Editor re Lydon Rochelle in NEJM Jan 2002 • Weiss J, Bartlett, L Massachusetts Dep’t Public Health • 4. Diagnostic codes (ICD 665.0 and 665.1) to identify uterine rupture not used exclusively for ruptures. • Massachusetts’ study – with chart review: • ½ of those coded to 665.0 & 665.1 – not ruptures • 1/3 of ruptures missed – (coded using ICD Code 674)

36. Letters to the Editor re Lydon Rochelle in NEJM Jan 2002 • Magee, D M.D., Massachusetts • 8. Critiques Greene’s assertion that “most reasonable women… would choose a caesarean if told uterine rupture raises the risk of infant death by a factor of 10,” by reminding readers this is a relative risk in a rare event. • Suggests instead the data from this particular article should be presented as: “the rate of perinatal death with a repeated cesarean is just over 3 in 1000 births; if you choose to have a trial of labour, the rate is just below 6 in 1,000 births.

37. Letters to the Editor re Lydon Rochelle in NEJM Jan 2002 • Koroukian, S, Case Western Reserve University, Cleveland OH • 7. Re-Green’s editorial: Greene discussed informed consent. Will the information presented to women undergoing primary caesarean include the increased risk of uterine rupture in future even without the spontaneous onset of labour? And the near certainty of caesarean next time?

38. Conclusion on VBAC Issue • Study conclusions of questionable merit are being used in isolation rather than as part of a synthesis of the literature • Publicity, not always merit, is dictating which studies become acceptable • Letters to the editor do not seem to be able to undo the political drive to increase interventions based on these studies’ interpretation • The more credibility the questionable studies are given the more intervention will be subsequently required