How much sleep is too much while pregnant?

Sleeping for more than nine hours per night, without disturbance, during pregnancy may be associated with late stillbirth, according to US researchers. Their study suggested that maternal sleep habits, including lengthy periods of sleep without waking more than once in the night, may be associated with foetal health.
According to a new international study, led by Michigan Medicine, sleeping for more than nine hours per night during pregnancy is linked with late stillbirth. The findings of the study were published in the journal Birth, to point out a link between long periods of uninterrupted maternal sleep and stillbirths that are independent of other risk factors.

As per the National Sleep Foundation, pregnant women must sleep 7 to 9 hours every night and sleeping beyond 10 hours can be termed as excessive sleeping during pregnancy.

Blood pressure is said to be at its lowest during sleep, but when someone is up, a rise in the nervous system activity occurs, causing an intermittent increase in the blood pressure. A brief change in the blood pressure is able to avoid a long stretch of low blood pressure. Low blood pressure has been related to foetal growth defects, preterm birth, and stillbirth.

While on the other hand, it is said that pregnant women should avoid waking up in the middle of the night. Sleep deprivation has been linked to poor pregnancy outcomes. There is evidence that sleep disruption is related to poor pregnancy outcomes, few studies have looked at the other end of the continuum, such as long stretches of uninterrupted sleep.