I purchased this in my second trimester, and did not get much use out of them at all.  Although it wasn't extremely tight, it was tight enough to unsettle my easily-disturbed pregnant gut.  I tried them several times and each time became very uncomfortable and ill.  I actually ordered the next size up thinking I might have just ordered to small, but the larger ones would just slide down and do nothing at all.  Perhaps some women have tougher stomachs than I do, but for me these didn't work well at all.