Stress Biomarker Associated with Infertility
Guest blogger, Carole Wegner
A recent study by researcher Courtney Lynch, an assistant professor of epidemiology at the Ohio State University Wexner Medical Center, showed that sustained levels of stress was associated with a longer time to conception. The study was performed by conducting questionnaires regarding perceived stress, testing for biomarkers of stress in saliva samples and charting the time to conceive. One stress biomarker (salivary alpha-amylase) was associated with increased time to pregnancy in data collected from 373 couples who participated in the study conducted from 2005-2009.
Alpha-amylase is an enzyme that is secreted into the saliva and aids in the first steps of food digestion that occur in the mouth. Alpha-amylase digests starches into the next smaller subunits called maltose. What does increased alpha-amylase production have to do with stress? It is not clear but one idea that has been proposed is that effectively converting starch into sugar for quick energy might be useful under stress when we might be getting ready for a fight or flight response. In any case, it is something that the body makes in greater abundance when it is stressed.
Women with the highest levels of alpha-amylase – presumably having the highest stress– were twice as likely to have longer times to conceive as those who had lower levels of this biomarker. According to the study authors, “This is the first US study to demonstrate a prospective association between salivary stress biomarkers and time to pregnancy, and the first in the world to observe an association with infertility”.
Does this mean that stress is a major cause of every case of infertility? No, but it does mean that it is likely one infertility factor, among many, that we should be aware of. “Stress” has become a sensitive word for couples who are struggling to conceive because they are often the recipients of the well meaning–but still irritating— advice “Just relax and you’ll get pregnant”. We are all aware that women can and do become pregnant even in stressful situations, for instance war, famine and situations in which people live with domestic violence. Even rape, a form of acute stress, frequently results in pregnancy if it occurs during the fertile window. So why is stress seem to be associated with infertility in some instances but not all?
It might be most useful to think of the ability to conceive as balance between positive and negative fertility factors. Stress is a negative factor that pushes the system toward greater risk of infertility.
Structural problems like missing or plugged Fallopian tubes are an absolute barrier to conception through sex . (IVF was invented to circumvent this barrier). Even the most zen-like peaceful non-stressed personality can not overcome this barrier. Similar absolute barriers to female conception include the absence of a uterus or eggs to ovulate. Likewise, the absence of sperm is an absolute barrier for men to conceive.
Other factors are not absolute barriers but make the body work harder to conceive. For instance, smoking can increase the time to conception. Yes, we all know the woman who smoked like a chimney before and during her pregnancy. These women are the exception and not the rule- not to mention that their children are born with a lower than normal birth weight and have lingering health issues from a less-than-ideal uterine environment! But maybe they were born with extra eggs, a healthy reproductive tract and even self-poisoning with tobacco toxins wasn’t enough to inhibit their fertility.
Weight extremes are also problematic for conception. Being morbidly obese or anorexic can interfere with the normal hormonal patterns necessary for fertility. Like stress, weight extremes by themselves, may not be enough to cause infertility, but coupled with other factors may become enough.
This study suggested that high levels of stress may be sufficient to increase the months needed for a successful conception. Hopefully, future studies may better define what is meant by “high” levels of stress and what role stress plays in relation to other infertility factors in causing infertility.
Carole Wegner, PhD, HCLD
President, Zygote Science, LLC.
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