Had unprotected sex( withdrawal method was successfull) on 19 January. But to avoid the unpredictable pregnancy, she took a Ipill on 20 january exact after 24 hours of sex. Her monthly mensturation was expected on 22 January. But it didnot happened. Today is 29 january but still no mensturation. We did pregnancy test too and it was negative. Hadnt used Ipill ever before. When can i expect her mensturation ??