What Are The Side Effects Of Loette Tablet?

Hi, i am a 20 years old girl.i was suppose to get my periods on 30th of dec which got delayed and i got them on 4th feb. My doctor has suggested me to take loetter tablets for 3 months to regularize my cycle. Do you think it is neccesaary i take them ? Will this pills have side effects on my body ? And is it okay if i dont take these pills ?