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Every pregnant woman should get a c-section.

Wait, no. No pregnant women should get c-sections.

Hmm, that doesn’t seem right either.

There are a lot of black and white things in medicine. Should we treat scurvy with vitamin C? Hard to argue against it. But there are many areas where hard and fast rules just don’t apply, and the c-section rate is a big one.

OK – we’ve decided that a 100% c-section rate is too high, and a 0% c-section rate is too low. What’s the right number? If your answer is “well, it’s too complicated to really assign a number”, you are in stark disagreement with the World Health Organization, which suggests that the appropriate rate is somewhere between 10 and 15% of live births.

Now a study appearing in the Journal of the American Medical Association suggests that that target might be too low. But I’m going to suggest that the whole idea of a target is misplaced anyway. But first, the details:

This is what’s called an ecological study. Instead of looking at the experience of individual patients, the study uses aggregate data, in this case, national c-section rates from all 194 WHO member states, and links them to that country’s maternal and neonatal mortality rates. The lowest c-section rate was 0.6% in South Sudan, likely attributable to a lack of appropriate facilities. The highest rate was 56%, in Brazil, for reasons that we can all speculate about offline.

Overall, the finding was that countries with higher c-section rates had lower maternal and infant mortality. C-section rates of less than 5% were associated with high rates of maternal mortality – about 0.4% and infant mortality – about 1.5%. These figures got better as the rate of c-section went up until the 20% c-section mark, where things sort of flattened out. In other words, no evidence of higher mortality as the c-section rate increased further.

The trouble with an ecological study is that you only have national-level data to work with. The authors adjusted for what they could – GDP for instance, but we lack information on a critical factor – complications during delivery.

The reason the 15% c-section target set out by the WHO doesn’t make sense is that it is a target that averages two different populations – women who need c-sections due to medical necessity, and women who don’t. There is evidence in the US that unnecessary c-sections increase maternal morbidity. Simultaneously, there is ample evidence that lack of access to c-section when it is necessary is a major problem in the developing world. While there are few absolutes in medicine, one could argue that the c-section rate should be 100% for women who need them, and pretty low for those who don’t. Rather than arguing whether 15% or 20% is the “right” national c-section rate, let’s turn our efforts in getting c-sections to the right people, regardless of the nation they call home.