While even one abortion is one too many there are many reasons or excuses given for them. Optimizing the race is probably the least frequent cause. Most are performed for convenience and as a form of birth control. Neither of these have anything to do with eugenics let alone Darwinism.
Eugenics is about a lot more than race, but the reality is that in America black babies are three times as likely to be aborted as white babies and that is directly related to abortion marketing.
Sex selection abortion is also a form of eugenics and this makes up a huge number of abortions.
The overwhelming number of babies that test positive for certain genetic conditions (like Down Syndrome) are aborted and this is eugenics.
Neither of these have anything to do with eugenics let alone Darwinism.
ALL modern-day eugenics is directly related to Darwinian and Malthusian principles.