Progesterone and oestrogen

Progesterone and oestrogen may be known as two of the key hormones involved in pregnancy and the menstrual cycle, but they also have the power to influence how well we sleep.

Progesterone, for example, has sleep-inducing properties – meaning fluctuations in the hormone can directly affect how sleepy we feel. This is because progesterone stimulates the brain to produce a neurotransmitter (a chemical messenger within the brain) called gamma-aminobutyric acid, or GABA. GABA’s prime function is to lessen the ability of our nerve cells to receive, create or send messages to other cells, essentially slowing brain activity and helping the body to relax in the process.

Because of this, elevated progesterone levels – like those that occur during pregnancy – can lead to higher levels of daytime sleepiness and increased sleep onset, meaning the time it takes you to fall asleep is reduced. However, while you may feel sleepier in the daytime during pregnancy, some of the other symptoms – such as heartburn and general discomfort – can cancel out the positive effects of the progesterone and make it harder to sleep at night.

Hormones and sleep: how oestrogen, progesterone and testosterone affect how well you rest