Will Bleeding Stop With Merina Insertion And Without Any Side Effect?

Good Evening Doctor !! I have been taking Regestrone as prescribed by my gynac...since i was bleeding for almost 20 days and it did not stop even after taking Pause MF. Subsequently, my gynac adviced me to go in for a Merina insertion which could be in my next mensural cycle. Please advice if Merina will be helpful and also does it have any side effect. I understand from a few friends that with Merina one tends to put on weight ! Please advice.