What Causes Delay In Periods?

Hello Dr., Its been 3 years we are married, We are trying for baby since last months. Doctor has told there is a cyst in o right overy but still they told not take it so serious n will try for a month. Dr prescribed Ovral G for my wife to remove the cyst but it didn't work. Also she taking MCBM 69 n Ebexid and I'm taking Evion LC all one per day since two months.She still not conceived but her periods got delayed by three weeks still waiting for it to happen. Are these tablets have any side effects, Wt is the reason such delay. Can v simply wait for periods to happen or need to consult doctor.? Its been 7 weeks for her last period. Thank you.