<s>[INST] I had a failed IVF attempt in May 2012. Have frozen embryos. So planning another ET. Doctor planning to put me on Gonapeptyl Inj since D2 in Oct 2012. Why is Gonapeptyl given prior to IVF? I was given the same before the first IVF. My periods are very regular but I have Thyroid issues. (Diagnosed with Grave s Disease and did RAI in 2009 Aug)Was on 75 and 100mcg thyroxine for the past 1 year and was going stable till the first IVF. It happened that I suddenly became hypothyroid after/during IVF. Since May, on 100mcg of thyroxine. My concern is why Gonapeptyl is given prior to this attempt of ET. Please answer.Thank you [/INST] Its given to schedule ET at specific date/time. </s>