Does Delayed Period After Having Protected Sex Indicate Pregnancy?

hi, m 23 male , i did intercourse with my gf last month, bt this time she dosent have her periods.
we use protection .bt once i put it in bare skin.
whats the chance for its pregnancy?
thats sure we want abortion if its like that.
is there any other safe method for abortion. we dnt want that it should if notice by her parents or any other problem would come..please help m in deep trouble..thanx