Circadian Rhythm and the Newborn Human

In the womb, your baby shares your natural body clock. It takes at least 3 months for infants to develop their own circadian rhythm.

It is normal and natural then for your baby to have no discernible day/night pattern to feeding and sleeping. They lack the hormonal control to establish one. And it is not something they can be taught, no matter how much parents try and self-styled "sleep trainers" promise. What is more likely to occur is various techniques and programs are tried until one "magically" works coincidentally as the natural development stage is reached and circadian rhythm begins to function. Most babies naturally begin sleeping longer stretches at night around 3 months.

"Melatonin, cortisol, body temperature, movement, blood pressure, digestion, and consolidated sleep are all part of the circadian rhythm. The newborn infant develops the components of circadian rhythm postnatally. A rhythm of cortisol develops at 8 weeks of age, melatonin and sleep efficiency develop at approximately 9 weeks, and body temperature rhythm and that of circadian genes develop at 11 weeks"."

Jacqueline Yates, DO