Ay mama, that's actually pretty normal at 38+ weeks, ang cervix natin talaga ay nag-open and close pa lang throughout pregnancy, hindi consistent yung dilation, kaya don't worry too much! A few of us moms experienced the same thing where one check showed dilation then the next closed up, it's really just how our bodies work as we approach labor, pero best to ask your OB about this sa next checkup mo para ma-confirm lang if everything's on track, since you're so close na to your due date.