Hi I have got pcos ,an very iregular periods,so the doc haz gave me norethisterone tabs,he said eat them 4 10 dayz an then stop an you wil get a widrawl bleed ,the day you bleed count 21 days onward an get your blood chkd if ovulation iz happening,my question 2 u iz,I thought after eating thez tablets the egg doznt realease so how can ovulation occur.plz reply 2 me bk