Your baby is spontaneously jerking or moving about because she is born with a number of reflexes:
The Moro reflex causes her to automatically arch her back, extend her arms and legs, and sometimes cry out when she senses a loud noise or a sudden movement. She may even do this in her sleep.
The Babinski reflex causes the big toe to bend back and the other toes to fan out when the sole of her foot is firmly stroked.
The step reflex makes your baby looks like she’s taking steps or dancing whenever her feet touch a solid surface.
The tongue-thrust reflex causes her to push her tongue out when something is placed on it.
The rooting reflex helps her find your breast and learn how to eat. When you touch your newborn’s cheek, lips, or mouth with your finger or nipple, she will turn her head to face you and open her mouth.
The “doll’s-eye response” is what happens when you lift your newborn and turn her to the left or right and her eyes stay fixed in the same position momentarily. This will normally disappear after about 10 days.
Her other inborn reflexes include grasping your finger when you hold it up to her and blinkingin response to a bright light or a sudden noise.