Hi doctor I'm 20 years old girl
I am having irregularity in periods from many months
I had no problem in periods in the early age of it but when I was 17 I started having problems I had ultrasound and other medical tests and all are clear
My doctor prescribed me a tablet "orgametril" but it is not helping me with the problem
Why is this so?
What to do to make it go regular? I'm really worried.

There aren't any doctors here, we're just average folk looking help out other folk. I looked up orgametril and am curious why he prescribed it when he had told you that all the tests for clear. It looks like it is a hormone replacement therapy or a component of HRT.

Regardless, how irregular are your periods? Has your thyroid been tested?

Some women have irregular periods, just a fact of life. Though if they're really irregular you might be concerned. IF you can't get answers out of this doctor, I would go to another one.