By: Dr. Shoshana Bennett and Dr. Richard L. Hansler
Staying healthy and happy throughout this exciting process of having a baby is a goal of every mother. Some recent discoveries about how light affects the human body are of special relevance to this topic.
It has been known for many years that exposing the eyes to light at night suppresses the sleep hormone melatonin. What is new is that it is principally the blue rays in ordinary white light that cause the suppression.
When a mother gets up at night and turns on a light in order to take care of her baby, she suppresses her production of melatonin. When she goes back to bed she may find she can’t sleep. About the time she finally falls asleep again, her baby cries and she again turns on a light. Once more, this cuts off her supply of melatonin. This results in upsetting her internal clock.
When she goes to bed the following evening she may find she can’t sleep, even though very tired. Her melatonin flow did not start at the normal time because her internal clock has been reset by the light exposure during the previous night. If this goes on for a number of nights, her body doesn’t know what time of day or night it is. She produces less and less melatonin, she sleeps very little and may fall into a state of depression. Disruption of the internal clock is well known to psychiatrists as a cause for depression.
Because it is now known that only the blue rays in ordinary light cause the melatonin suppression, it is easy to avoid the problem. All that is required is to use lightbulbs in the nursery and bathroom that don’t produce blue light.
Alternatively, the new mother may simply slip on a pair of glasses that block blue light and she can then go anywhere in the house without fear of losing her supply of melatonin. Because a father also can develop postpartum depression, he needs to take the same precautions.
Many pregnant women find they are getting up during the night. For them, using blue blocking glasses and/or light bulbs makes sense for the same reasons.