Sleeping position associated with late pregnancy stillbirth

A research paper recently published in the British Medical Journal reports a strong association between sleep practices and stillbirth late in pregnancy. The authors set out to...

"...determine whether snoring, sleep position, and other sleep practices in pregnant women are associated with risk of late stillbirth."

The compared date for 155 women with a singleton stillbirth after 28 weeks of pregnancy (and without congenital abnormality) with 310 women with pregnancies and gestation matched to those in which stillbirth occurred as controls. They examined maternal snoring, daytime sleepiness, and sleep position at the time of going to sleep and on waking. Their data were striking for the association with sleep position in particular:

"No relation was found between snoring or daytime sleepiness and risk of late stillbirth. However, women who slept on their back or on their right side on the previous night...were more likely to experience a late stillbirth compared with women who slept on their left side... Women who got up to go to the toilet once or less on the last night were more likely to experience a late stillbirth compared with women who got up more frequently. Women who regularly slept during the day in the previous month were also more likely to experience a late stillbirth than those who did not."

Sleeping on the back or right side conferred a 250% increase of stillbirth late in pregnancy than sleeping on the right side. The results for sleep position and frequency of rising for the toilet during the night make sense considering the vascular dynamics. Daytime sleepiness is frequently associated with decreased oxygenation due to apneas or hypopneas during the night. The authors' conclusion is a call to action to prevent the devastating heartbreak of late pregnancy stillbirth by better advice based on more science:

"This is the first study to report maternal sleep related practices as risk factors for stillbirth, and these findings require urgent confirmation in further studies."

Meanwhile, it seems prudent to prefer a right side sleeping position while awaiting further confirmation. Also, clinicians, pregnant patients and their partners should be alert to signs of sleep disordered breathing.