Sunday, October 03, 2010

Are some Irish mothers "too posh to push"?

The use of C-section to deliver babies has tended to go up over time and has generated some concern. It is, after all, a significant operation and can have negative consequences. For example mothers are less likely to breastfeed after a C-section.

It is sometimes argued that mothers elect to have C-sections as they are “too posh to push”. Leaving aside the question of whether this is a good or bad thing: is it actually true? Using the Growing Up in Ireland data I estimate some simple probit models predicting the probability of elective and emergency c-sections. Household income (equivalised & in log form) is positively associated with having a C-section. But the coefficient for emergency c-section is almost twice as big as that of elective. This doesn’t fit in with a simple story of affluent mothers choosing to have c-section. I have no idea why income would have such an effect on emergency C-sections.

Mother’s education, interestingly, seems to have no effect (& remember education is generally seen as a better measure of socio-economic status than income) nor does a measure of social class (not shown here) nor does whether the mother smoke or drank during pregnancy. Factors that do predict a c-section include the mother’s BMI and her age (for the elective case) and the baby’s birth-weight (for the emergency case). Clearly many other factors may influence these outcomes & not all of which are in this data.

So while there is clearly a connection between how well-off a mother is and whether she delivers via a C-section its not at all clear that it is a simple case of "money talks".


(1)

(2)


elective

emergency

log income

0.0168*

0.0292***


(2.41)

(3.96)




mother's educ

-0.00209

0.00246


(0.73)

(0.81)




birthweight

-0.0101

-0.0322***


(1.77)

(5.20)




born on time

0.0693***

-0.0590***


(8.73)

(6.58)




" early

0.193***

-0.00267


(7.86)

(0.23)




" very early

0.126*

0.214***


(2.44)

(4.26)




partner

0.0186

-0.0114


(1.82)

(0.96)




girl

-0.00154

-0.0202**


(0.24)

(2.95)




Mothers BMI

0.00346***

0.00427***


(5.32)

(6.22)




" smoke

-0.00852

-0.00414


(1.62)

(0.78)




" drink

-0.0121

-0.00234


(1.93)

(0.35)




Age

0.00565***

-0.000325


(8.71)

(0.48)

N

7020

7020

pseudo R2

0.065

0.055

Marginal effects; Absolute t statistics in parentheses

* p<0.05,**p<.01,***p<.001


2 comments:

Peter Carney said...

"I have no idea why income would have such an effect on emergency C-sections."

Kevin, interesting post. one reason for the income finding might just be family size.

If you have one birth by c-section then subsequent births will be by c-section in the vast majority (~90%) of cases. So one idea is that maybe what you're finding here is that poorer mums are having relatively more routine c-sections (i.e., relatively fewer emergency c-sections) than richer mums cause they are having more children than richer mums.

Another, less probable reason, is that some mums may have a preference for the 'au natural' birth but then elect for c-section in the 11th hour. it might be reasonably, if you accept the hypothesis, that it's easier for richer mum's to switch due to insurance. If the c-section is not scheduled, it would probably fit the emergency box best.

so, if you could control for birth-order or family-size, and pmi status, i would wager you'll explain the odd finding on income; notwithstanding the education finding.

Kevin Denny said...

I am not sure about that argument but maybe, I will check if I have family size in the data.
If a mother decides late in pregnancy that she wants a C-section I would have thought that would still be an elective- an emergency one has to be decided for medical reasons?