For a lady with regular 28 days cycle, ovulation (release of egg) happens on 14th day of the cycle. If the egg gets fertilized(sperm enters the egg successfully), then that lady has conceived and she will not get her periods. If the egg was not fertilized, she wouldn't have conceived and she will get periods after 14 days
If hormone imbalance occurs like in a lady with PCOD, with weight gain, ovulation doesn't happen and cycle becomes irregular
Next Steps
Lifestyle changes ( weight reduction)
to see gynecologist