What happened for me is that at 41 weeks I was sent to the hospital for an ultrasound, with fetal movement monitoring appointment planned for the day after.
What actually happened is that the ultrasound showed my fluid levels were very low, so I was sent straight after for fetal monitoring (they strap the monitor disk things to your belly, and you click a little button whenever you feel a fidget).
In my case, the baby was fine, but they wanted to induce (which is a whole other 3 day story ending in EMCS - which I want to emphasise, whilst unpleasant was just because these things are, the staff and treatment couldn't have been better)
Had the ultrasound shown everything normal, then I'd have gone on at least another week before they'd have been suggesting intervention.
Remember that by now the baby has very little room, and hopefully their head is getting wedged into the right position (turns out my little guy was at an awkward angle, which is why he wasn't descending, and the induction wasn't working) so they do move a little less, and a little less strongly. BUT if you don't feel movement for an unusually long amount of time (I'd feel something every few minutes if I sat and concentrated) then you need to get seen.