what are the reasons of jerky movements in babies and why it comes

A. Hi. Please check with your paediatrician once because It happened to my son when he was six months. Thiugh it was not frequent but atleast once or twice in a day he used to do a jerking type of gesture(not exactly jerking). We consulted with a paediatrician and came to know that his iron level was not up-to the mark. We started with iron drops and now it's all fine.