It feels like someone is drilling on top of your uterus. (nicolejardim.com)
This is a darker line extending from the pubic bone to the top of the uterus (fundus), usually showing up for first time moms around the third month. (verywellfamily.com)
The strong muscles at the top of the uterus push down and release, guiding your baby toward the cervix. (babycenter.com)