California is diverse in presenting both urban and rural hospital settings, education levels, income levels and ethnicity and so we like this paper on the merit of good demographics to draw from and the educated observations made by the authors.  Zweifler et al reported in the Annals of Family Medicine that they also studied the type of data collected on a birth certificate and took into consideration the definitions of infant and mortality rates as utilized on California’s birth certificates versus the World Health Organization’s definition.

     In 1999 ACOG issued its recommendations for VBAC and the guidelines restricted VBAC delivery “attempts” to be made only in hospitals that could respond immediately to emergencies.  The study’s objective was to compare the infant and maternal mortality rates before and after the guidelines’ implementation and secondly, the affect on rural women as their local hospitals were less likely to have immediate access to emergency physicians and services.  In 2004, ACOG reaffirmed its policy and the American Academy of Family Physicians (AAFP) challenged ACOG’s stance in 2006 by analyzing the California Birth Statistical Master Files from 1996 through 2002, three years before and three years after ACOG’s policy was issued and before it went into full effect.  Bad news travels fast.

Some relevant background provided by the authors of this paper:

  • Percentage of babies born via cesarean in the U.S. in 1965, 4.5%; in 2002, 26.1%.
  • The VBAC lash may be a trend that actually began to show in 1997 and ACOG’s policy is a result of obstetricians discomfort with VBAC for a few years prior to the 1999 ACOG statement.
  • Federal reports in the 80’s and 90’s promoted VBAC as a safe and reasonable alternative.  In 1994 and 1995 ACOG promoted VBAC as well for a woman with one previous cesarean of a lower uterine segment incision (low horizontal incision).
  • Hospital birth certificates categorized Electronic Fetal Monitoring and Ultrasound exams as “complications.”  Our authors did not place those records into the ‘complications’ category (bravo!).
  • Certificate of Live Birth information was used to categorize the delivery method as “Successful”, “Failed” (including delivery assistance other than cesarean) and “Cesarean Section-Repeat.”
  • The Certificate of Live Birth codes “unsuccessful attempt at vaginal birth after cesarean section” as a “delivery complication.”
  • The Certificate of Live Birth codes maternal death within 72 hours hours of delivery as a delivery complication whereas the World Health Organization (WHO) definition of maternal death is within 42 days.
  • The authors calculated infant deaths using the WHO’s definition, newborns living less than 28 days.
  • Newborn weights were categorized as follows: <1500g [3lbs) very low birth weight, 1500g to 2499g[3lbs to 5.5lbs] low birth weight, 2500g to 4000g [5lbs to 8.8lbs] normal birth weight and >4000 [8.9+ lbs] large birth weight.
  • Rural hospitals may fare better as high risk women identified are transferred to urban hospitals that are better equipped.
  • Neonatal morbidity – hypoxic-ischemic encephalopathy and the maternal morbidity – uterine rupture – are not given Certificate of Live Birth codes.  The very reason(s) why ACOG issued their guidelines … and it/they can’t be tracked!

In the years studied 10.9% of all hospital births in California were to women with previous cesareans.  Our researchers believe their results which show a higher VBAC success rate (83% versus the 79% reported by Wall, Deutchman et all in 2005) is due to the lack of clear categorizing of planned and unplanned VBAC deliveries using birth certificate data. 

MATERNAL DEATH RATES     1996-1999          2000-2002
Attempted VBAC                      2.0%                      8.5%
Repeat Cesarean                      8.7%                      11.9%
Total Maternal Deaths w/i 72 hours of delivery: 35
The authors’ results are as follows (Zweifler et al):
  • Very low birth weight babies fared the same with VBACs as reported by Riva & Teich in American Journal of Obstetricians and Gynecologists in 1961 (remember our previous post’s claim that there have been no improvements in high risk infant mortality rates in three decades?)
  • The above may be attributed to the fact that these births are classified as VBAC even if there was a planned cesarean.  Women with very low birth weight babies who attempted VBAC but “ultimately had cesareans (classified as a failed VBAC) had similar neonatal mortality rates as women giving birth to very low birth weight infants by repeat cesarean section.”  Here’s what shows the quality of these researcher’s knowledge.  They give you a very educated reason for the difference: “..the differences in neonatal mortality rates for infants of very low birth weight may be less a function of attempting a VBAC or electing to have a repeat cesarean section than a reflection of (existing risk) factors.”
  • VBAC very low birth weight infants are precipitous and therefore did not have a chance to receive the benefit of steroids prior to birth that have been shown to improve their outcomes (ah, see our previous post on the validity of technology’s effect on ‘saving’ our babies).
  • No significant difference in maternal deaths for attempted VBAC v. elective repeat cesarean although it is not possible at this time to narrow down maternal mortality specifics.
  • Proportion of older women and black women who attempted VBAC did not decrease after 1999 and that is consistent with national VBAC trends as reported by Menacker in a National Vital Statistics Report of 2001.
  • VBAC deliveries declined faster in rural than in urban hospitals in 1999 and that could be attributed the decline in number of family physicians able to provide obstetrical services.  Chalk one up to ACOG for running family physicians, our nation’s previous whole health care experts, out of business.
  • Repeating: Neonatal morbidity – hypoxic-ischemic encephalopathy and the maternal morbidity – uterine rupture – are not given Certificate of Live Birth codes.  The very reason(s) why ACOG issued their guidelines … and it/they can’t be tracked!
  • Results are dependent on proper coding of birth certificates which are here proven to be subject to misclassification.
  • Attempted VBACs were 24% prior to ACOG’s 1999 guidelines and were 13.5% immediately after the guidelines were issued.
  • “Neonatal and maternal mortality rates did not improve despite increasing rates of repeat cesarean delivery during the years after the ACOG 1999 VBAC guideline revision.  Women with infants weighing [greater than or equal to] 1,500g encountered similar neonatal and maternal mortality rates with VBAC or repeat cesarean delivery.”
     Perhaps we should have titled this post “Chalk One Up for ACOG.”  Certainly, they legally outmaneuvered family physicians for the right to attend births.  You see with the rise of cesareans and the decline of VBACs how could a family physician fight to keep his/her clients let alone practice best birth care protocols?  How long will you be able to afford the right to exercise your health care options?