Science Blog

  • How much do unborn babies sleep? (Things We Don’t Know about Pregnancy Series #16)
    1 week

    We can’t measure the brain activity of a human foetus – not whilst they’re inside their mother. But we’re really interested. What happens to a baby’s brain as it’s developing, and what does this tell us about our own and the developing process of sleep?EEG (electroencephalogram) reading via Wikipedia Commons.Researchers into brain activity have performed EEG (electroencephogram) exams on premature babies, and monitored eye movement in the womb to learn about sleep cycles, although big errors with these kinds of measurements are common. They have, however, detected REM (rapid eye movement) sleep from around 7 months, when the brain cycles in and out of restful and REM (rapid eye movement) sleep every 20 to 40 minutes. From 7 months onwards, foetuses mostly sleep (90-95% of the time at 32 weeks, 85-90% by 37 weeks). After it develops, REM sleep increases and increases, reaching a lifetime high of 12 hours a day just before the baby is born.Very little is known about foetus sleep before this. For example, we don’t know if sleep and sleep cycles suddenly or more gradually develop with the foetal brain. New research into lambs has shown that foetuses enter a dreaming-like brain state weeks before REM sleep starts[1]. As well as learning more about sleep, this study could help us figure out how the brain develops and when it is most at risk.Equally, neurons in the brain develop much earlier, with those responsible for sleep present long before REM sleep is seen. Continue to full article »