Abortions are not exclusive to any economic status, so some of them would be welfare children.

The fact that abortions are not exclusive to any particular socio-economic groups doesn't change the fact that an overwhelming majority of abortion procedures involve women with low incomes.

According to the National Institutes of Health:

there are substantial disparities in abortion rates in the United States, with low-income women and women of color having higher rates than affluent and White women. In 2008, the abortion rate for non-Hispanic White women was 12 abortions per 1000 reproductive-age women, compared with 29 per 1000 for Hispanic women, and 40 per 1000 for non-Hispanic Black women.2 Disparities in abortion rates also exist by socioeconomic status (SES), with women with incomes less than 100% of the federal poverty level (FPL) having an abortion rate of 52 abortions per 1000 reproductive-age women, compared with a rate of 9 per 1000 among those with incomes greater than 200% FPL. In analyses assessing both income and race/ethnicity, both are independently associated with abortion rates.2