Have any of you mamas had to change the kind of undies you wear during/after pregnancy?

I recently had to buy a different style of underwear (granny panties) becaue mine just werent comfy anymore. The style i wore before would just squeeze and rub me all wrong. I would get red welts in my undie area. I havent gained any weight yet, maybe its just pregnancy causing me to be overly sensitive to things. But i love how comfy these cotton grannies feel!!!