My friend had a protected (condoms) with his gf.. but stil she took an i pill to be on saferside.....?

15 dys afer this she had bleeded for about 2 to 3 days was not lke a normal period as he says..... but my friend said that she has not got her periods till now after that.. it was supposed to be on Nov 6.. Any idea why is this so.. is there any chance of she being pregnant or is it any effect caused of taking the tablet even thoughcondom was used....he is askng for suggestions n i do not have any idea....woud lookforward for some good answers which will help my friend..