Light Elimination Therapy for the Treatment of Infertility (LET)

by One More Soul Staff

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Joy DeFelice R.N., B.S.N., P.H.N. Director, Natural Family Planning ProgramProvidence Sacred Heart Medical Center, Spokane, WA 99220-2555 USA

Presentation and French translation. Françoise Soler

Light Elimination Therapy for the Treatment of Infertility (LET)

ABSTRACT: Infertility remains a common and often unresolved condition afflicting certain couples. Numerous animal studies have demonstrated that alterations in the light-dark cycle can affect reproduction as mediated by the pineal gland and its hormone, melatonin. To examine whether a similar disruption could affect human fertility, a pilot study was conducted with infertile women enrolled in a Natural Family Planning program.

OBJECTIVE: To examine the association between illumination present during sleep, abnormal menstrual cycle parameters, and infertility.
STUDY DESIGN 1: Forty-eight women were studied over a 10-year period. They were taught to chart their menstrual cycle following standard Natural Family Planning methods on three consecutive cycles. At the last class, subjects were informed about the hypothesized effects of ambient light on their reproductive hormones. They were provided with a list of light sources and a rating system to gauge intensity, allowing each subject’s total light score to be calculated.
Subjects were then instructed to decrease their score as much as possible for six consecutive cycles. Their menstrual cycles were examined before and after light minimization looking at 6 parameters: menstrual flow; pre-follicular; follicular phase; ovulation; luteal phase; cycle length.

RESULTS: Initially, none (0%) of the subjects had all parameters within normal range in any of three consecutive cycles. An abnormal follicular phase was found in 96% of the women, followed by luteal (64%) and ovulation (58%) phase abnormalities. The mean light score was 37.5. Establishment of a darkened sleeping environment was associated with a significant reduction in abnormal parameters within 6 cycles. Twenty-six (54%) of the women became pregnant within that same time frame, a rate equivalent to a fertile non-contracepting population.
Two of these women had a history of habitual miscarriages, and both completed the pregnancy.

The mean light score at time of conception was 4.6, representing a reduction of over 87%. 15 conceived during the first 3 cycles of darkness; 11 others during cycles 4 to 6 of darkness. 11 were < 30 years old; and 15 > 30 years old. 8 pregnancies occurred during the months of April to September, and 18 between October and March. Darkness was maintained during the pregnancies. All had a healthy delivery. 30 women (62.5%) had previous physician fertility consultation. 25 then had infertility procedures, but it was after LET that 13 (52%) conceived.
Among the 12 men with abnormal tests before LET, 6 conceived after LET.

DISCUSSION: It is known that the brain (specifically the hypothalamus and pituitary glands) is the cycling center for the hormones that govern the menstrual cycle. In early 1978, Joy gained particular insight into why and how these light influences might work within the brain from research conducted on laboratory rats by R.J Wurtman, and particularly two papers1, 2. “The pineal gland has undergone extraordinary changes with evolution. It has developed into an unusual kind of gland, a neuro-endocrine transducer. This means that this gland can take an
outward stimulus (light) which is relayed through a special optic (eye) nerve route to the pineal gland, which can then convert this light impulse to hormonal output (melatonin)”. Joy postulates that melatonin is stored in the hypothalamus and from that location influences the woman’s reproductive hormones. “Therefore, if the definite 24 hour rhythm of melatonin (normally low during the day and high during the night), is disrupted, then the normal progression of hormonal events of the menstrual cycle can also become disrupted.” Joy has collated formal details to evaluate the sleeping environment for light sources3.
a) Artificial light sources located in the bedroom (with different scores if the light is white, green, blue, or red).
b) Contributing factors that increase the level of light in the sleeping area (as thin window shades, large windows, mirrors, snow on the ground…) by artificial or natural light sources.
c) Inside artificial light source reflecting into the bedroom (as a light on all night in the hallway or reflecting from another room…)
d) Outside artificial light source reflecting into the bedroom (as streetlights or neighbor’s….) Eliminate the light source itself for the best results. In situations where the light cannot be eliminated entirely, darker window coverings; or a sleep mask; or folded cool material placed snugly across the nose and eyes will block out the light. Other helpful ideas are available.

CONCLUSION: The presence of ambient light during sleep can have a fundamental and independent effect on a woman’s reproductive function. A simple regimen of adequate light exclusion can be an effective, economical and non-invasive treatment of a certain subset of infertile couples. Well-controlled studies are required to validate these results, including assays of reproductive hormones and melatonin to delineate the physiologic mechanisms involved. Couples can correctly identify their days of potential fertility in each cycle through STM instruction. A sufficient level of darkness during sleep, and then maintaining that darkness, helps to stabilize all the hormonal phases of the menstrual cycle. These phases can be observed in the woman’s STM charted patterns. Couples also report greatly improved sleep after darkening.

1. Wurtman RJ The pineal and endocrine function Hospital Practice 1969;4:32-7
2. Wurtman RJ. The effects of light on the human body. Scientific American 1975;227:60-77
3. DeFelice J. Eleventh Edition (2009).The effects of light on the menstrual cycle: also infertility.Before and after clinical observations of light elimination therapy
Les effets de la lumière sur la glaire cervicale dans le cycle menstruel, observations cliniques by SERENA
Questionnaire pour évaluer la pollution par la lumière Françoise Soler


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