Vaginal Birth After Cesarean in California: Before and After a Change in Guidelines

Zweifler et al in Vaginal Birth after Cesarean in California: Before and After a Change in Guidelines explored the impact of the 1999 ACOG guideline revision on vaginal birth after cesarean (VBAC) rates.(1,2) The authors attempt to measure the impact of the guideline revisions on the rate of VBAC in different populations by region, ethnicity, and education. If we want to demonstrate the true impact of these guidelines, other variables must be studied.

The authors reported attempted VBAC rate and percent decline for the Black, Hispanic, and Asian populations, but these numbers do not accurately reflect the impact of the guidelines. Because of the data collection method, unintentional VBACs were included in the attempted VBAC numbers. Lack of obstetric care, precipitous delivery, and preterm delivery are all classified as VBAC by this method. Physicians have less control over unplanned VBACs, therefore the measured rate of change has been underestimated. This effect is more pronounced in populations that have a higher rate of unintentional delivery. For example, African-Americans have a higher rate of preterm labor.(3) Inadequate education, health care access barriers, and socioeconomic problems that contribute to preterm labor and out-of-hospital delivery are higher in some ethnicities and regions.(3,4)

Barriers to adequate health care in minority groups are most pronounced in controversial interventions such as whether to schedule a repeat C-section or plan a VBAC. In our community, many obstetricians are unwilling to accept the medico-legal risk and increased time commitment of attempted VBAC in pregnancies where they are unlikely to get paid. Language barriers make the extensive consent for VBAC difficult. Migrants with C-section histories often have difficulty obtaining operative reports required for VBAC. Hispanic women in our community choose to stay with a more culturally friendly practice that no longer provides VBACs instead of transferring to an office providing both options.

Restrictive ACOG VBAC guidelines combined with cultural and economic barriers complicate an already difficult issue. In a medical situation where there are two viable options, is there a loss of choice in some groups? Addressing this issue is vital to developing a culturally responsible community with equitable medical care.

1. Zweifler J. et al. Vaginal Birth after Cesarean in California: Before and After a Change in Guidelines. Ann Fam Med. May/June 2006. Vol 4(3):228-234. 2. ACOG Practice Bulletin #54: vaginal birth after previous cesarean. Obstet Gynecol. 2004.Vol 104:203-212. 3. Newton, Edward R. Preterm Labor, Preterm Premature Rupture of Membranes, and Chorioamnionitis. Clinics in Perinatology. Sept 2005. Vol 32(3):571-600 4. Institute of Medicine report on racial and ethnic disparities: Unequal Treatment; Confronting Racial and Ethnic Disparities in Health Care (national Academies Press, 2002)

Competing interests:   None declared

Dr. Viswanathan points out the importance of accounting for pregnancy complications when evaluating studies of delivery outcomes. In fact, as we reported in our study, in a regression analysis including only newborns of normal and large birth weight, pregnancy complication was the only significant predictor of neonatal mortality.(1). However, suggesting that the major finding of our study was that the risk of neonatal mortality is higher with attempted vaginal birth after cesarean (VBAC) than with repeat cesarean birth is a misrepresentation. Our two major findings, as stated in the conclusion of our abstract, were: neonatal and maternal mortality rates did not improve despite increasing rates of repeat cesarean delivery during the years after the American College of Obstetricians and Gynecologists (ACOG) 1999 VBAC revision, and women with infants weighing 1500 gms or more encountered similar neonatal and maternal mortality rates with VBAC or repeat cesarean delivery.

The authors believe our study significantly contributes to the evidence base by identifying that excess neonatal mortality when attempting a VBAC is isolated to the less than 1500 gm birth weight category. In our article, we propose plausible explanations for this observation. Although our study was limited to neonatal mortality due to the constraints of birth certificate information, our data suggests studies that found higher rates of neonatal complications should be reviewed to see if complications are also concentrated in very low birth weight infants.

Ultimately we agree with Dr. Viswanathan that women considering VBAC should be provided with a balance presentation based on evolving evidence, including the encouraging findings regarding VBAC outcomes found in our study.

(1)Zweifler J, Garza A, Hughes S, Stanich MA, Hierholzer A, Lau M. Annals of Family Medicine; 2006;4(3): 228-234.

Competing interests:   None declared