Hello,
The cause of irregular periods could be due to hormonal imbalance, stress, chronic illness, polycystic ovarian disease, thyroid gland disorders or diseases, pituitary gland tumors or cyst,
galactorrhea, prolactinomas etc. You should consult a gynecologist
and get examined
and investigated if the irregularity in periods persists.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided.