Hallow Dear, On 4th day of the menses, the egg is nor released and hence there is no possibility of pregnancy even if you have intercourse on this day. The egg is usually released 14 days prior to the next expected menses. However, you are having PCOS and had menses following Novelon; hence it is difficult to predict the day of egg release (ovulation) in you. The best option for you is to monitor ovulation. You can do it either by Ovulation Monitoring Home Kit or by Ultrasonography. When the ovulation takes place, utilise that day for your sexual intercourse. This will increase the possibility of pregnancy. The egg is having life of 24 hours while the sperms are active for 72 hours. So try to have at least every alternate day frequent intercourses around the day of ovulation. If you are monitoring ovulation by ultrasonography, keep in mind that usually a healthy ovum is released when follicle is between 18 mm to 21 mm size. If the follicle is mature but ovulation does not take place naturally, the Gynaecologist may give you hCG injection to cause the ovulation. Then you should have intercourses. I hope this helps you. Dr. Nishikant Shrotri