Well I may have found the weight gain culprit...TOM! You may be thinking well didn't you know it was coming?! The answer is no, I have had an IUI (mirena) for over a year and a side affect is not having a consistent period each month. I haven't had a TOM for months now so when I woke up and saw Aunt Flow came to visit I said Aha! That must be part of the weight gain. Only time will tell I'll have to see if my theory is correct next WI.