Study: Reproductive Issues Due to Circadian Rhythm Disruption

Holy Hormones Honey! Living outside the body’s circadian rhythm wreaks havoc on endocrine system functioning.  Women’s lives are not driven by testosterone. We live with a natural ebb and flow of hormone signals that affects all other systems in the body.  When we ignore that rhythm, we begin to have reproductive issues. Infertility rates are skyrocketing.  Teenage girls are put on synthetic hormones injections and implants at an earlier age – and at the most fragile time of their lives – menarche. Women were revered as Goddesses because of this innate alignment with the inner and outer worlds. For more information see Female Mystique: The Three Phases of Eve.

Off the Clock: Disrupted Daily Rhythms Hinder Fertility in Mice

Mice whose sleep patterns were altered had more difficulties conceiving and carrying pregnancies to term. The findings may have implications for women trying to conceive.

Scientific American
By Sarah Fecht
May 23, 2012


“My biological clock is ticking.” The phrase typically pops up in movies about middle-aged women who want to start a family before menopause makes it impossible. But a new study published May 23 in PLoS ONE indicates that another clock may also be important for females trying to conceive: the one that regulates our waking and sleeping cycles.


A strong body of evidence links daily wake-sleep cycles to feminine reproductive cycles. When scientists remove a female mouse’s suprachiasmatic nucleus—the pacemaker in her brain that regulates daily circadian rhythms—her estrous cycle ceases, and she becomes infertile. In human females, working night shifts and frequently traveling across time zones has been associated with menstrual irregularities, reduced fertility and a greater number of negative pregnancy outcomes such as low birth weight, preterm birth and miscarriage.

But “one of the issues with these epidemiological studies,” says Keith Summa, a medical and doctoral student at Northwestern University, “is that there are other factors associated with shift work that may also be playing a role.” For example, women who work night shifts also tend to sleep less. “Our study provides stronger evidence that reproductive problems are due to circadian disruption itself,” Summa says.

Summa and his colleagues divided a group of 48 inseminated female mice into three groups. Then they fiddled with the rodents’ sleep patterns by changing the lighting conditions in the cages. The control mice experienced a normal light-dark cycle: 12 hours of “daylight” and 12 hours of “nighttime,” on a set schedule that never wavered.

The researchers shifted the light-dark cycles for the two less-fortunate groups of mice.  In one cage, the morning lights went on progressively later; mice began the experiment with a “daytime” of 6 a.m. to 6 p.m., but then after five days, researchers shifted the light forward by six hours, so that daytime would last from noon to midnight instead. The five-day period allowed the mice to adjust to each new schedule before it shifted again.

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Environmental Perturbation of the Circadian Clock Disrupts Pregnancy in the Mouse


Author: Leslie Carol Botha

Author, publisher, radio talk show host and internationally recognized expert on women's hormone cycles. Social/political activist on Gardasil the HPV vaccine for adolescent girls. Co-author of "Understanding Your Mood, Mind and Hormone Cycle." Honorary advisory board member for the Foundation for the Study of Cycles and member of the Society for Menstrual Cycle Research.