In a letter to the outgoing president, Koop recommended that a major federally funded longitudinal study of abortions health risks was the only way to secure definitive answers. His proposal for a major study died in the Democratically controlled congress, however, when abortion advocates argued that the appeal for such research was politically motivated and a waste of tax payer dollars.
Koop is right; a study like this isn't very meaningful. Women who have abortions are far more likely to have all sorts of problems in their lives. Excluding women with prior psychiatric care helps, but only a little.
Even a detailed study like Koop is suggesting has limited value. Women who get abortions may be fundamentally different than women who don't, in ways that can't be captured by any metric. Proof of causation - abortion causes poor mental health - will always be tenuous.
Of course, in our "smoking is dumb" PR society, maybe the stigma of being cukoo will work better than the stigma of murderous selfishness.