Ever wonder why babies suck their thumbs? #pediatrics This is an ultrasound of an unborn baby thumb sucking in the womb!Ultrasound observations of fetuses as early as 15 weeks have revealed these little guys sucking on their thumbs! This ‘sucking reflex’ is believed to play a role in preparing the child to begin breastfeeding at birth! This reflex is paired with the rooting reflex, in which a newborn searches for a food source (nipple seeking) & turns his or her face in the direction of a stimul