Wednesday, November 4, 2009

My response to WHO Press Release criticism

Henci Goer, representing Lamaze International, has criticized the CCA's latest press release, 'WHO admits: There is no evidence for recommending a 10-15% caesarean limit'. Her criticism can be read here, and this is my response.

Firstly, inside the red circle in the WHO table that Henci has highlighted, you will see a small letter 'c', and the note beneath the table reads: 'See Section 2.5 for a discussion of this range.'

Since Henci has not reproduced this discussion, I will do so here. It reads:

"Earlier editions of this handbook set a minimum (5%) and a maximum (15%) acceptable level for caesarean section. Although WHO has recommended since 1985 that the rate not exceed 10-15% (125), there is no empirical evidence for an optimum percentage or range of percentages, despite a growing body of research that shows a negative effect of high rates (126-128). It should be noted that the proposed upper limit of 15% is not a target to be achieved but rather a threshold not to be exceeded. Nevertheless, the rates in most developed countries and in many urban areas of lesser-developed countries are above that threshold. Ultimately, what matters most is that all women who need caesarean sections actually receive them."

With regard to minimum and maximum acceptable levels, it says:"Both very low and very high rates of caesarean section can be dangerous, but the optimum rate is unknown. Pending further research, users of this handbook might want to continue to use a range of 5–15% or set their own standards."

My response to Henci
1. The WHO handbook states (above) that users 'might' want to continue to use a range of 5-15% or set their own standards. Given that the WHO itself states (also above) that 'there is no empirical evidence for an optimum percentage or range of percentages', it is entirely your prerogative to choose to continue advocating a percentage threshold that has no basis in evidence.
I do not. I prefer to advocate countries setting their own standards, and in doing so, to explore a far wider body of research than the three studies that you (and the WHO) refer to in your post (more on these below).

2. This is an indisputable fact: On the subject of cesarean rates, the WHO has said in 2009 that 'the optimum rate is unknown'. This is what our press release states and while this fact may not fit in with your birth ideology, that does not make it any less factual.

3. You infer that our press release did not go far enough in terms of quoting the WHO handbook accurately, and in this context, you refer specifically to the extract 'despite a growing body of research that shows a negative effect of high rates'. Please look again - our release does include this line of text and we made no attempt to avoid or hide it.

4. I am open to debating the subject of cesarean deliveries, and in particular, my focus is on demonstrating that a planned prophylactic cesarean at 39 weeks for women planning a small family is a perfectly legitimate birth choice in preference to a trial of labor (since these women are adversely affected by strategies to reduce cesarean rates to 15%).
But what I object to strongly is your effort to censor a press release that does not agree with your point of view. Medical News Today and have both been contacted with the specific request to remove our press release from the internet, and to use your own words, 'shame on you' for resorting to such tactics.

5. Furthermore, in your chat with visitors to your site at the bottom of the page, you are praised for contacting Medical News Today, and you write: 'Your welcome! This is my idea of fun.' Again, I don't think there's anything funny about attempts to censor an opposing viewpoint to your own.

6. In March this year, I spoke at a seminar on the subject of cesarean rates, and my presentation included many studies to support the point of view that a 15% rate is unrealistic and unwarranted (as you know, the CCA is not the first to criticize the WHO's 1985 recommendation). I can provide you with a copy of this, and would like to note here that I received very positive feedback from many midwives and natural birth advocates in the room that day - and that the doctor with the 'opposing viewpoint' to mine in our seminar even admitted that a 15% rate is unachievable. Here is an extract on the subject of infant mortality for example:

"Since extraneous socioeconomic factors affect the U.S. infant mortality rate (deaths <1>Singh and Kogan, 2007), it is less relevant to the delivery method than the fetal mortality rate (deaths at 20-27 gestational weeks or ≥28 gestational weeks), neonatal mortality rate (deaths <28>MacDorman and Kirmeyer, 2009), (Kung et al, 2008)
Northern America, together with Australia (which has a cesarean rate of 30.8%), has the lowest regional stillbirth rate and one of the lowest regional neonatal mortality rates worldwide. The WHO says it has 'shown that one third of stillbirths take place during delivery - deaths that are largely avoidable and closely linked to the place of and care provided at delivery.' (Neonatal and perinatal mortality: country, regional and global estimates, WHO, 2006)
A UK study of 65 maternity units incl. 540,834 live births and stillbirths found that a 'higher intervention score and higher number of consultant obstetricians per 1000 births were both independently and significantly associated with lower stillbirth rates.' (Joyce et al, UK, 2004)

My criticism of WHO's 2009 handbook
1. Its recommendation on cesarean rates is now open to ambiguity. While I am glad that (after much lobbying) the WHO has finally put in print that it has no evidence for recommending an optimum cesarean rate, it is a pity that its statement remains open to this type of debate.

2. It refers to 'a growing body of research that shows a negative effect of high rates' and references three studies, '(126-128)', but there are numerous other large and contemporary studies that demonstrate very positive outcomes with cesarean deliveries, and these are not mentioned in this area of the WHO's discussion at all.

How can the WHO ignore (for example) that women in the UK (where national data on elective and emergency outcomes is separated, unlike the U.S., which only separates primary and subsequent cesareans) are less likely to die following a planned cesarean than any other birth type? Or studies from Sweden that demonstrate greater levels of satisfaction following planned cesarean births than planned vaginal deliveries? Or the latest study from Canada - of 40,000 births - that concludes: ‘elective pre-labour caesarean section… at full term decreased the risk of life-threatening neonatal morbidity compared with spontaneous labour with anticipated vaginal delivery’. And the cesarean group in this latter study were breech deliveries (understandably more complicated than cesareans with cephalic presentations) while the vaginal delivery group were cephalic presentations...

3. When I interviewed Dr Monir Islam, Director of the WHO’s ‘Making Pregnancy Safer’ program last year, he told me that he agrees with the ACOG’s 2007 and NIH’s 2006 statements on maternal request cesareans: that they are ethically justified following individualized consultation.

His exact words were: 'A woman should have the right to decide. Why should she not have the right to decide? 'It should be an informed decision; the doctor needs to give the woman all the information she needs, and then the woman should decide whether she wants a cesarean section or she doesn’t want a cesarean section.'

Clearly, maternal request cesareans add to national percentage rates of cesareans, and this is another reason why a 15% threshold is unrealistic in North America and the UK.

4. The three studies referred to as 'a growing body of evidence' are seriously flawed in the context of this debate when quoted in isolation, and particularly in any debate about maternal request cesareans with no medical indication (the notes below refer to maternal request because this is the context I first wrote about them in, but they are still relevant here because any attempt to reduce national cesarean rates to 15% would have to involve the refusal of maternal request).

*Issues with the Deneux-Tharaux et al study
If you read the research in full, it is evident that in the two causes of death where the majority of maternal mortality occurs, CD does not result in more cases of death than VD. For example, the risk of postpartum hemorrhage (the most common cause of death here, at 38.5%; n.25) is as high with VD as it is with CD. In fact, the maternal mortality risk is higher for CD in the three causes of death that occur least: Venus thromboembolism (n.7 of 10 total); Puerperal infection (n.4 of 5 total) and Complication of anesthesia (n.4 of 5 total), which equates to 15 out of 20 deaths in these areas (the total number of deaths was 65). This is the source of the 'triple the risk' headlines.

Furthermore, Deneux-Tharaux writes: 'It must be noted that 3 of the 4 deaths due to complications of anesthesia in this study occurred after general anesthesia, whereas the 4th death occurred after spinal anesthesia. This suggests that general anesthesia at cesarean delivery is associated with a much greater mortality risk than regional anesthesia.'

PMHull: General anesthesia is usually administered in an emergency CD, not an elective CD. Therefore, any deaths following the use of general anesthesia in an emergency CD should not be used to analyze the safety of an elective CD where spinal anesthesia is used.

Deneux-Tharaux: 'Cause specific mortality could not be analyzed separately for prepartum and intrapartum CD because the numbers of deaths were too small.'

PMHull: The separate analysis of prepartum and intrapartum CD is vital in any research that draws conclusions on the comparative safety of elective CD versus VD. The mix and match of analysis, results and conclusions of 'all CD' and 'elective or maternal request CD' is not an effective measure. Furthermore, maternal mortality following intrapartum CD is a measure of risk that needs to be applied to the category of 'planned vaginal delivery' and not a planned CD. This is important because risk can only be assessed at a birth 'planning' stage, and whether desired or not, the fact is that a planned spontaneous VD can have the outcome of instrumental and/or emergency cesarean delivery.

PMHull: It is also worth pointing out that the three mortality areas, where greater risk with cesarean is demonstrated, are largely preventable in quality hospitals with competent surgical personnel, using medical knowledge that has existed for many years. The data used in this study was from a period spanning 1996 to 2001. It is inadequate to make any conclusive statements using data that is over a decade old, especially when data exists in other studies from births that have occurred more recently.

*Issues with the MacDorman et al studyAlthough the researchers applied the NIH's 'intention-to-treat' recommendation, they have not accounted for one of the most important recommendations by the NIH, which is to wait until 39 weeks EGA for planned cesarean delivery with no medical indication. Instead, the study defines low-risk births as "singleton, term (37-41 weeks' gestation), vertex births, with no reported medical risk factors or placenta previa and with no prior cesarean section." This is important, because while a baby delivered at 39 weeks EGA is certainly not risk free, the neonatal mortality rate is most likely lower than the 1.73 reported here; and this is especially relevant since it is cases of 'no medical indication' that MacDorman et al are questioning.

Planned vaginal deliveries (even those for low risk women) can last beyond 41 weeks, and there is documented evidence of a 'small but significant' risk in fetal mortality beyond this point (Divon et al, 1998), and also after 40 weeks. (Caughey et al) Measuring mortality up to 41 weeks alone may have provided PVD with improved statistical outcomes in this study.

Self-reported limitations of the study include concerns about the accuracy of reporting specific data items on the birth certificate.
MacDorman et al: 'Reporting for the major variables in this study (neonatal mortality and method of delivery) is generally considered to be excellent; however, underreporting of individual medical risk factors and complications of labor and delivery on birth certificates has been documented. is possible, based on either poor reporting or because the risks involved items not recorded on the birth certificate, that the group including cesarean delivery with no labor complications or procedures was still an inherently higher risk group, and those risks accounted for both the decision to perform a cesarean section and the subsequent neonatal death. It is also important to note that birth certificate data cannot be used to infer the intentions of either mothers or their practitioners, so these data do not address 'maternal request' cesareans.'

Dr Marian MacDorman said at the time of the study: ‘Even though we don't know exactly that it's elective cesarean delivery, it is probably the best approximation we can make.'...

PMHull: Critics noted in media reports that because birth records often don't accurately reflect whether a CD was medically necessary, this study could be comparing apples to oranges.

Also, again, death that occurs following an emergency CD follows an 'attempted' or 'planned' vaginal delivery (VD). Therefore, while clinicians and women are being advised to use study data to inform their birth planning, then the mortality results should be compiled in such a way that reflects original birth plans. Grouping all CD outcomes together (i.e. emergency and elective) cannot help inform the birth planning stage, and in fact grouping emergency CD outcomes with VD outcomes would be more accurate than grouping them with planned CD.

Issues with the Villar et al study
This study focused on countries in Latin America, where there are differences in standards of health care as a whole compared with North America and the UK. That is not to say the research should be dismissed; only that there are other studies in North America and the UK (that demonstrate more positive outcomes with cesarean delivery), and these should surely be included in any WHO referenced 'body of evidence'.

As a final note, readers may be interested to know that another study by Villar et al (Maternal and neonatal individual risks and benefits associated with caesarean delivery: multicentre prospective study), published one year later in 2007, met with a great deal of criticism in the form of Rapid Responses on the BMJ wesbite. Headlines included:

A prospective study is still needed Maureen Treadwell (1 November 2007)
Definition of "elective" is misleading Amy B. Tuteur, Sharon, MA USA (2 November 2007)
Avoid interfering with physiology when possible David JR Hutchon (2 November 2007)
Term and preterm deliveries Gordon C S Smith (3 November 2007)
Not much help, really Robert G Buist (17 November 2007)
Somewhat misleading Zhong-Cheng Luo (19 November 2007)
Caesarean section risks and maternal choice Jonathan H West (20 November 2007)
Elective Caesarean section safest form of childbirth Michael P Wyldes (23 November 2007)
Contrary to Epidemiological Logic Dr Mudassir Azeez Khan (19 December 2007)
Anesthesia Effects Martin Dauber (27 December 2007)
New research finds lowest maternal mortality rate with elective cesarean delivery Pauline M Hull (30 July 2008)

5. To reiterate, it is not that I am suggesting that these three studies should not be used in an evidence-based assessment of cesarean outcomes; only that they should not appear as a group in isolation and defined as a 'body of research' that proves negative outcomes with high rates. They belong as part of a much larger body of evidence, which includes studies with very positive birth outcomes following cesarean delivery (including mortality and severe morbidity for both mothers and babies).

Henci, we may just have to agree to disagree on the issue of 'optimum' cesarean rates, and unfortunately, it would appear that the WHO's handbook lends itself to encouraging such an arrangement.

If you wish to engage in respectful dialogue about this issue please contact Penny Christensen at She has volunteered to respond to any concerns or questions regarding the CCA's release. You may wish to read BTCanada’s website at for background information first.

No comments: