Social Darwinism is disgusting
concise.
Social (and, indeed, physical) Darwinism is the first thing I thought of as well, but why are you so disgusted with it? The survival of the fittest is natural, and has selected your kind for success. "The survival of the fittest"? Then how do you explain the continued existence of the hippopotamus, who can only feed on dry land but cannot even survive on dry land during the sunshine?
I understand what is meant, but "survival of the fittest" - and "success" in Darwinist terms as well - is a badly phrased and easily misunderstood and abused term, and should perhaps be retired. We're actually talking the survival of anything sufficiently fit to meet a certain minimum standard, and not under massive pressure from fitter competition. Anything that can find itself a niche.
Alleviate the social burden of nurturing an unwanted human? That's what free childcare, welfare, and family tax credits are for
You're talking of alleviating the social burden of not nurturing an unwanted human. Which also exists.
(And no, I do think the cost should be covered for the economically destitute. Basically, it makes no sense to deny access to abortions to those who subjectively need it the most. If we want the procedure to remain safe and legal (as in "safe legal & rare", that is). What would be the point of offering legal abortions to the middle class while very poor (and very young - one of the two reasons for my opposition to parental notification laws) still recourse to coathangers?