During pregnancy, a large number of women experience sleep disturbances. Now, a new study suggests that pregnancy-associated sleep perturbations could have a lasting effect on the physical and mental health of the baby. Researchers at the Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, used highly controlled animal experiments to evaluate the effects of sleep restriction during pregnancy on the brain development of offspring.

Sleep is a basic necessity for survival. Lack of sleep can lead to a weakened immune system, affect both short and long term memory, and has been shown to cause accidents and errors in the workplace. Disturbances in sleep in pregnant women have been well documented, with studies showing that such disturbances are associated with increased preterm birth, labour pain, and depression. In spite of this, very little is known about what effect such disruptions may have on the health of the child. 

“Adverse effects of poor sleep in different age group populations have been studied to a certain extent. However, not much attention is paid to sleep disturbances caused during pregnancy,” said Kamalesh Gulia, senior author of the study.

Sleep consists of two distinct phases — non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. In this particular study, researchers restricted pregnant female rats from sleeping for 5 hours each day during the third trimester of pregnancy. The protocol abolished both NREM and REM sleep in these rats. Once pups were born to these dams, the researchers analysed their sleep-wake profiles during the first three weeks of life.

Gulia and her team observed that the pups born to sleep restricted dams had higher active sleep (precursor of adult REM sleep), but lower quiet sleep (precursor of adult NREM sleep) and wakefulness when compared to control pups.

The researchers next examined the effects of maternal sleep restriction on the brain activity of the offspring using electroencephalography (EEG) analysis. This test detects electrical activity in the brain using a set of electrodes that are attached to the scalp. The researchers observed changes in the properties of different brain waves in the brains of pups whose mothers had faced sleep restriction. Coupled with the increase in the ratio of active to quiet sleep in these pups, this observation indicated an immature brain at birth and delayed development of networks for sleep-wakefulness. Interestingly, these signs of delayed brain maturation in the pups born to sleep restricted dams are similar to signs of delayed maturation observed in premature babies.

“This study highlights the importance of sleep during pregnancy, but it also suggests that neonatal sleep monitoring can be used as a tool for early assessment of retarded brain development,” said Gulia.

“This is a voluminous study by the sleep research pioneers of India,” said Bindu Kutty, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, who was not involved with the study. ​“It is a truly unique study that has massive translational value. To further understand the developmental pattern, the study can be conducted on the same rat model at different time intervals,” she suggested.

This study provides an important insight into the ways maternal and offspring health are intertwined, and suggests that sleep problems should be monitored, identified, and taken seriously by doctors working with pregnant women.

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