Thanks for query,
You have hormonal
imbalance leads to delayed ovulation resulted in to delayed periods.
our Pitutary gland in brain secreates precursor of hormone that advised our adrenal gland to produce sex hormones .Any disturbances in this leads to less blood levels of hormones disturbs your ovulation process cause you no periods or delayed periods.
Your doctor has prescribed you oral hormonal theraphy that mimics like nature hormone so that the process becomes regular.Once it gets regular you get ovulation & you can become pregnant.