He, sallallaahu ‘alayhi wa sallam, used to do Tahneek for them:

An-Nawawi said: “Tahneek, which means to chew on a date or something similar, then to wipe it on the palate of the child. If it is done without dates it is fine, but to use a date is better, for its sweetness is very beneficial to the baby.”

Modern science has confirmed the medical benefits of doing Tahneek for the growth and development of the child. Narrations regarding Tahneek show that it should be done with dates or something sweet, and it is the first thing that should enter his body. That is because a newborn child could suddenly die if one of two things happens: either a drop in his blood sugar or a sudden decrease in his body temperature if the surrounding weather is cold. The blood sugar (glucose) level in the newborn baby is often low, which could lead to dangerous results, such as the baby refusing to breastfeed, or limpness in his muscles, or difficulty breathing, or causing a blue tinge to the skin. It could also lead to complications such as stunted growth or mental retardation.

The cure to this is simple and that is to administer glucose dissolved in water, either in his mouth or by way of injection, and this is what happens when doing Tahneek with a date. Studies have proven that doing Tahneek also strengthens the muscles in the mouth and tongue, preparing the newborn to breastfeed easily.