Answer:
The number of abortions probably does not change a whole lot if they're legal or illegal so the number of available for adoption children would likely stay the same. The two numbers that would go up are the number of mothers suffering from secondary problems like infections/death and (without proper medical oversight) the number of late term abortions would probably rise as well (further balancing the total number of abortions).
Before it was legal 5,000-10,000 women died a year in the USA from abortion and the number would return to that range if it became illegal again.