The 31st week of pregnancy is the penultimate week of the eighth month of gestation. At this time, the foetus is so large that there is not enough room for it to move around inside the uterus. As a result, a woman may not be able to feel her baby as much.
Also, if the foetus is not yet in the cephalic position, it will soon change to prepare for birth. Its organs are already formed and the lanugo is disappearing.