Lu Libing touches the belly of his pregnant wife, Mu, as they pose for pictures during an interview with Reuters at their home in Ganzhou
Lu Libing touches the belly of his pregnant wife, Mu, as they pose for pictures during an interview with Reuters at their home in Ganzhou, Jiangxi province March 13, 2014. Lu knew he had only one choice as the birth of his third child approached. He couldn't afford hefty fines that would be meted out by Chinese authorities, so he put the unborn child up for adoption. On the Internet he found "A Home Where Dreams Come True", a website touted as China's biggest online adoption forum, part of an industry that has been largely unregulated for years. Demand for such websites has been fuelled by rural poverty, China's one-child policy, limiting most couples of only one child, and desperate, childless couples. To match story CHINA-ADOPTIONS/ Picture taken March 13. REUTERS/Alex Lee

In a recent report published in the journal Fertility and Sterility, it was suggested darkness was most essential for women who wanted to get pregnant or are expecting a baby, as it determines the reproductive health in women.

It also helps protect the devolving foetus, said Russel J. Reiter, study researcher and professor of cellular biology at the University of Texas Health Science Centre in San Antonio.

Previously published researches were analysed by Reiter and a summary of the role of malatonin was provided. Melatonin is a hormone secreted by the pineal gland in the levels and circadian rhythms on successful reproduction in females. When exposed to darkness, the pineal gland in the brain secretes a hormone called melatonin, which is important in women wanting to conceive or who have already conceived as it protects their eggs from oxidative stress, explained Reiter. When women ovulate, the hormone's strong antioxidant properties shield the egg from free-radical damage.

"Every time you turn on the light at night, this turns down the production of melatonin. If women are trying to get pregnant, maintain at least eight hours of a dark period at night. The light-dark cycle should be regular from one day to the next; otherwise, a woman's biological clock is confused," he advised.

Turning on the lights at night curbs the production of the hormone in women, and this affects the foetal brain which may not get the proper amount of melatonin to regulate the function of its biological clock, he said.

Animal studies have revealed that this hormone may determine the behavioural problems in newborns. This has led some researchers to speculate that similar disruptions of the light and dark cycles when a woman is pregnant may be related to the rise in attention-deficit/hyperactivity disorder (ADHD) or autism spectrum disorders in young children.

Reiter said, "We have evolved for 4 million years with a regular light-dark cycle that regulates circadian rhythms. We have corrupted this with the development of artificial light, which disrupts the biological clock at night and suppresses levels of melatonin. There is a biological price to pay for disturbing the light."

He also stated that staying in darkness had nothing to do with sleep. So women could also make sure that the bedroom is kept dark with no light peeking in. Even if you can't sleep, do not turn on the lights as this will help adequate production of melatonin which is required for the foetus, he advised.

Melatonin is required for the normal functining of every individuals body, a drop in the levels can lead to Seasonal Affective Disorder (SAD) and depression. Supplements are prescribed to insomniacs and those undergoing sleep diorders. Pregnant women, however, must not take melatonin supplements as they can have side effects such as morming grogginess, drowsiness, fatigue, lower body temperature, vivid dreams and a chamge in blood pressure. The side effects will disappear on dicsontinuation of the supplement.

Though they are safe in small doses, it's best to consult a doctor before taking it.