When I was pregnant with DD I was sure she was having fits. I would feel jerky, twitchy movements all the time.
When she was born i figured out what it was.. When she is falling asleep, and for about ten minutes into the sleep cycle, she twitches. Mostly in her hands, but her whole body jerks too. She still does it to this day (she is 11).
Something similar? Mention it to your Dr or midwife if you're worried xx