Hello
As you mentioned that you are taking
folic acid tablet , this don't causes any weight gain.
Other tablet is duphaston or
dydrogesterone for regularization for menstruation.
You are also want conception.
Here in your case two points are important .
As you are having
irregular menstruation ( so for which your gynae advised duphaston ) .
The next thing is you are gaining weight .
The third thing is you didn't get pregnancy ( because you want a baby , according to query ).
The side effects of duphastone are dizziness, nausea, headache , fatigue, irritability,
abdominal pain & distension.
No doubt this is a good drug for menstruation regulation and above all this don't causes any weight ,so you can take this tablet as advised by your gynaecologist.
One thing more I want to suggest you , please get in
ultrasound of both ovaries for any cysts ( weight gain, irregular bleeding may be due to this disease ).
So consult one more gynaecologist and get his opinion ( 2nd one ).
Good luck.