For now, the Senate has rejected an abortion amendment similar to the one in the House bill which has passed. However, further challenges could emerge.
The NY Times Economix blog cited several experts who agreed that the Stupak amendment in the House was a significant change from the status quo. Private insurers would be unable to offer abortion services in plans on the insurance exchange - furthermore, the insurance exchange is expected to grow over time, as more small and medium companies opt into the exchange. There is the possibility that insurers might sell separate abortion riders, which would be legal. However, five states presently restrict the availability of abortions in plans regulated by their insurance commissioners and all indications are that markets for riders have not developed.
Experts at George Washington University, led by Professor Sara Rosenbaum, have a detailed analysis.