Exposure to light while sleeping may harm fertility in women and lower their chances of getting pregnant, latest research shows.
These findings were found equally important for pregnant women.
The study, conducted by researchers from the University of Texas Health Science Center, San Antonio in US, found that staying in complete darkness for at least eight hours was crucial for the proper functioning of the reproductive system and for keeping the developing baby safe in the womb, Live Science reported.
Continuous exposure to light at night reduces the production of melatonin, a hormone secreted by the pineal gland in the brain during darkness. The hormone possesses anti-oxidant and anti-cancer properties and plays a major role in circadian rhythms. It is the same hormone that protects eggs from oxidative stress and other damages, according to the researchers.
"Every time you turn on the light at night, this turns down the production of melatonin," study researcher Russel J. Reiter, a professor of cellular biology at the University, told Live Science.
"If women are trying to get pregnant, maintain at least eight hours of a dark period at night," he added. "The light-dark cycle should be regular from one day to the next; otherwise, a woman's biological clock is confused."
Similarly, sufficient levels of melatonin production in expecting mothers are required for the proper development of the foetus. Evidence shows that exposure to night light in pregnancy can increase the risk of behavioural problems in children.
Reiter recommended women who are trying for a baby or already pregnant to create a healthy, dark sleep environment and to avoid using blue and white light. Pregnant women should take care not to get exposed to light during an eight-hour sleep cycle every day, particularly during the last stages of pregnancy, Reiter said.
Findings of the study have been reported in the journal Fertility and Sterility.
Role of light exposure on infertility has been a source of concern from a long time. A research released in 1981 revealed that exposure to extremely bright light similar to the daylight turned off production of melatonin in humans and affected fertility, The New York Times reported.
Meaning of Complete Darkness
Using light –blocking fabrics for window curtains can help create a healthy sleeping environment. The room should be in complete darkness, i.e. nothing in the room should be visible at least 15 minutes after switching off the light. Use towels or aluminium foil to block lights coming from outside- either through the space down the door or through the windows, according to Katie Singer, a certified fertility educator and author of "The Garden of Fertility."