TSH level increased from 2.5 to 4.5

My doctor got my TSH tested before IVF.it came around 2.5 , he said we are good to start with IVF.We did our first IVF cycle and it failed ,meanwhile I also started taking prenatal tablets with biotin in it.

I again got my TSH tested before we go for our second round and my TSH results came back as 4.5!!!!!

In two months my TSH has jumped from 2.5 to 4.5...Can anyone share your experiences about prenatal/ IVF effecting TSH levels...Why is this happening to me!!!i have already started taking birth control pills for my second IVF cycle n now this!!!!