Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice.
There are many causes of delayed periods like
pregnancy,
anaemia,
thyroid disorders, stress,
anxiety, etcetera. If you are sexually active, it would be better to get a urine pregnancy test to rule out pregnancy.
If you are not sexually active, it could be the other causes like anaemia, thyroid disorders, stress or anxiety. Since you have already taken
regestrone, wait for another 4 more days and if still no periods, visit your gynaecologist.
She might ask you to do a couple of blood tests. Meanwhile, don't be anxious about why your periods haven't started. Anxiety itself can further delay the onset of periods. So relax and wait for a couple of days.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. Divya Kuttikrishnan