Four months of regular sex without success in conceiving a child is still not enough time to assume that you or your partner are experiencing sterility. Instead, one full year of practicing unprotected sex is considered an optimal period for conception. You don’t have to worry about the discharge coming out of the vagina after sex. It may contain some sperm but most of the sperm stays in the vagina. You may continue practicing unprotected sex during the fertile days of your cycle. The fertile days are the days around ovulation. Ovulation happens about 14 days before the next period comes. You may consult a gynecologist if you don’t conceive after one year of trying.