That is of course true, because C sections are primarily used in high-risk pregnancies and in emergencies. But what you actually care about is the counter-factual: if a given set of deliveries were "natural" rather than a C section, would mortality go up or down? It's hard to develop studies to answer that counter-factual. But there is good evidence that C-section rates are negatively correlated with mortality (i.e. they lower deaths) up to about 20% of deliveries, and have no positive or negative effect beyond that: http://www.skepticalob.com/2017/10/more-wailing-and-gnashing....
Indeed, there is new evidence that "natural" births are in the long term bad for mothers, dramatically increasing the risk of things like incontinence later in life: http://www.skepticalob.com/2018/03/what-if-c-sections-are-be.... As a practical matter, these negative effects will impact far more women than differences (if any) in morality rates.
