Hello dear Undestand your concern Femilon is newer contraception pill and has very few side effects. But remember, you should take regularly at specific time. (make habit to take regular by putting reminder in mobile), So you can take it safely to regularize the period. Following are minor side effects: weight gain, change in appetite, breast changes, tenderness and soreness, bloating, nausea, vomiting. But it is different from subject to subject and you can reduce by taking at specific time. Hope this may help you Breast regards Dr. Sagar