Well, if one believes in respecting the `will of the people', then I don't see why you wouldn't go ahead and honour the vote (against abortion). I wouldn't differentiate between capital punishment/abortion/leaving the EU.
Personally however, I would be very careful to put anything in a referendum for a host of reasons. People may be badly misinformed on the issues involved, easily manipulated (eg by politicians with ulterior motives), and it can really become divisive for a country where there was no real division before. Brexit is such an example.