Do Babies Sleep in the Womb?

Do you ever wonder why babies are sometimes active and sometimes not? We can certainly feel them kick about and do other little movements, and at other times they are quiet. But do they sleep in the womb?

To the best of our knowledge, babies spend most of their time in the womb sleeping [1]. Compared with the rapid eye-movement (REM) and non-rapid eye movement (NREM) sleep states that are typical in adolescents and adults, foetuses and preterm infants have a less clear-cut contrast between sleep states [2].

Their equivalent of REM sleep, referred to as active sleep, is distinguished based on facial and body movements and variations in heart rate, and breathing. Quiet sleep, which is their version of NREM sleep, has a more regular heartbeat and breathing pattern. There is also little body movement during this stage. As gestational age increases, your little one starts to develop a more even ratio of active and quiet sleep.

Why do foetal babies spend so much time sleeping?

Deep REM sleep allows our brain to establish neural connections. Although this dynamic process never stops throughout life, it is largely developed while we are in the womb. Neural connections are essentially pathways that run through our brain, allowing each area to talk to the other. This prompts your baby’s ability to hear, move, process sensations and respond to specific noises, such as your voice.

Do babies yawn in the womb?

So, we’ve established that babies sleep quite a lot while in the womb, and that this is super important to their development, but a big question remains - do they yawn while they’re in there? Interestingly, science has found that your little one is likely yawning from as early as the first trimester [3].

It has also been observed that foetuses yawn approximately 25 times a day [4]! While there is some debate over whether babies actually yawn or are simply opening their mouths (possibly to even burp!), foetal yawning can sometimes help medical professionals determine the health of your baby.

The science is still in its early stages but some debate that it may provide an indicator of a baby’s central nervous system development.