These are soooo comfortable.  I wear mine 24/7 over my maternity bra.  Some of my tank top straps cut into my shoulders as I twist and turn in my sleep.  Not these.  They fit so comfortably.  I was a 32A/B not pregnant, then grew to a 34DD pregnant.  Im definitely bigger than that now while breastfeeding.  I bought the Large size and it fits perfectly.