Wednesday, February 27, 2013

The Power of Numbers - the Math of Maternity Care

When I am working, I spend most of my time immersed in numbers and thinking about indicators that can be used to measure health and the health care system. As a result, I am acutely aware of the power of numbers and the importance of understanding what numbers are available, how the numbers used are calculated, what the numbers include or exclude, and what it might mean when the numbers change over time. As a result, I read statistics and particularly health statistics, with a different lens. Specifically, I am much more critical of the numbers I see - as I know that the story being told by the numbers depends critically on the numbers used and how they are being interpreted. I have become particularly aware and interested in the numbers used (and not used) to tell the story of maternity care, particularly in the news media. The thing is numbers have power, and by focussing on the wrong numbers or interpreting the numbers in the wrong way - there may be unintended negative consequences for women and their babies. Currently, the most commonly used statistics in the news media with respect maternity care are: infant mortality, cesarean section rates, and cost estimates - and, sadly these numbers and they way they are used are telling a story which may be leading many women, care providers, and health administrators astray.

Infant mortality is the number of babies who die from birth to one year of age relative to all babies who are born alive. As a result improvements in the rate of accidental death or access to paediatric care - perhaps as a result of better car safety, sleep safety or better health insurance coverage - will lower the rate of infant mortality. While fewer very young children dying is a very good thing, saying it is the result of better maternity care is a bit of a stretch. Unfortunately, many media reports make that stretch and equate infant mortality rates with maternity care.

With respect to cesarean section rates - little quality information can be gained by looking at the headline rate (number of c/sections as a share of all births). This is because nothing is known about how many of those cesareans are planned cesareans, how many are emergent cesareans, how many are maternal choice, how many have complications, how many are traumatic, or how many avoid much more severe complications that would have occurred in the absence of a cesarean. Given a choice between a third or fourth degree tear, an instrumental delivery, or an oxygen deprived baby - most moms are better off and would likely choose a cesarean section. Further, the cesarean section rate is not risk adjusted, and as such it is nearly impossible to say whether or not any specific rate is too high or too low without knowing the characteristics of the population being served - is it older? are the mothers of a healthy weight? are there other co-morbidities (heart problems, kidney problems, diabetes, etc.)? When the relative risks of cesarean are reported on, both emergent and planned cesareans are frequently lumped together and as a result the risks of an emergent cesarean are underestimated while the risks of an elective cesarean are overestimated. Lastly, the only thing the cesarean section rate tells us is how many cesareans were performed, the supply of cesareans, but it tells us nothing about how many cesareans should have been performed, the demand for cesareans.

Finally, the cost estimates that are available are at best flawed in that the costs included are only the immediate costs (those that occur within 30 days of the birth), and the costs of cesarean lump together emergent and elective surgeries and as a result do not reflect the costs associated with planned mode of birth. From an economics perspective, spending money on birth (including spending money on cesareans or other interventions) might be a good investment if it avoids other costs in the long run, such as those costs involved in coping with a damaged pelvic floor, birth trauma, or a birth injury.

There are better statistics that already exist - like the perinatal mortality rate. There are also better statistics that could exist - like the rate of unmet need (ie. epidurals requested but not given), the rate of adverse mental health outcomes, and patient reported outcome measures. Numbers are powerful, unfortunately it is quite possible that when it comes to maternity care, the focus is on the wrong numbers.


  1. I was having a great convo with my pelvic floor physiotherapist about the cost of pelvic floor issues.

    Pelvic floor physio is not covered by my provincial health insurance...that already makes vaginal birth look cheaper.

    Did you know that in elderly women that purchase incontinence products the average yearly expenditure is $1100?

    But what we really wanted to know was what is the productivity cost due to female pelvic floor issues related to childbirth? What if you have a prolapse and have a job that requires heavy lifting? What if, like me, you can't count on regular bathroom breaks? Are women off work but not on benefits (silently disabled), do they change jobs? reduce hours? retire early?

    And what about exercise? If exercise is reduced due to pelvic floor issues, what is the cost to society from the increased morbidity of heart disease and lower life expectancy?

    And what about the costs associated with depression and anxiety?

    All currently unmeasured costs that result in vaginal birth looking cheaper than c-s.

  2. And if the woman decides to attempt to correct her pelvic floor issues surgically at a later date - what of those costs?

    I just think the whole issue of cesarean and vaginal birth has been looked at myopically - and that women are generally in a good position to assess which planned method of birth is in their own best interests after a conversation with their health care provider about the relative risks and benefits of the available methods (planned cesarean and planned vaginal birth).