Nearly 25 years ago, my husband and I were having dinner with friends who were expecting their second child — and I was having trouble getting pregnant.
“Just relax,” my friend’s husband offered, adding that his wife got pregnant after a weekend getaway to visit the in-laws in Florida.
My stress levels skyrocketed. I didn’t respond. But if I had, I’d have told him that all those theories about how stress curtails fertility are drivel from the Brontë era.
But now, I’m not so sure.
The notion that stress can muck up a person’s fertility goes back centuries and has seeped into popular culture. In the third season of “Downton Abbey,” the character Matthew Crawley, an heir to his family’s estate, worried that a World War I injury had rendered him infertile. “My dear Mr. Crawley,” a doctor told him, “anxiety is an enemy to pregnancy.”
In real life, medical experts from the 19th century claimed — without evidence — that the stress of higher education could damage a woman’s childbearing abilities. Women, the argument seemed to go, had a finite amount of energy that was dispersed to either their brain or womb, but not to both. Dr. Edward H. Clarke, M.D., a professor at Harvard Medical School who specialized in primary care and the study of the ear, wrote in his 1873 book, “Sex in Education; Or, a Fair Chance for Girls,” that a woman may “work her brain” over math, botany, and chemistry, but she will “divert blood from the reproductive apparatus to the head.” Therefore, he concluded, women should not be educated in the same way as men.
Women’s rights activists were irate.
By the 1940s, doctors developed a term for women they considered to be too anxious, ambitious or not in tune with their own stress to get pregnant: psychogenic infertility. They believed that career-driven women who were struggling to conceive were not down on their luck merely because of run-of-the-mill infertility, but because they harbored anti-maternal unconscious thoughts that hijacked hormones from their brains and ovaries. Women’s magazines were replete with anecdotes from formerly infertile women who got pregnant after they quit working and learned to enjoy homemaking. Many obstetricians prescribed a few months of psychoanalysis. During a talk in 1947, Dr. Viola Bernard, M.D., an eminent psychiatrist in New York City, said that the “unconscious dread or aversion to pregnancy can indirectly disturb ovulation and hence conception,” claiming such thinking led to sterility.
The emergence of so-called test-tube babies in the 1980s, along with the machinery that could manipulate sperm and eggs, turned everyone’s attention away from the potential impact of emotions on fertility. With the ability to precisely measure stress hormone levels and to use computers to analyze troves of biological data, a handful of scientists began taking a closer look at how stress might impact fertility — and vice versa.
“It’s the chicken and egg question,” said Alice Domar, Ph.D., executive director of the Domar Center for Mind/Body Health at Boston IVF and an associate professor of obstetrics, gynecology and reproductive biology at Harvard Medical School. “We know women and men going through treatment are very stressed, but does stress cause infertility?”
Turns out, that question is challenging to answer. Few large, conclusive studies have been done on the topic. Because most studies are small and rely on notoriously unreliable self-reported data, their conclusions are hard to parse. But according to what researchers do know, there are a few hints that stress may have at least some impact on fertility.
A study published in the American Journal of Reproductive Immunology in 2018, for instance, found that among 45 couples who were undergoing in vitro fertilization, women who had higher blood levels of a specific kind of molecule that rises with stress were less likely to get pregnant after one cycle of I.V.F.
Other studies have also linked reduced fertility with increased concentrations of salivary alpha-amylase, an enzyme that’s secreted by salivary glands in response to stress. One, published in 2014 in the journal Human Reproduction, found that among nearly 400 women in the United States, those who had the highest levels of salivary alpha-amylase were 29 percent less likely to get pregnant after a year of trying — and more than twice as likely to be declared infertile — than those who had the lowest levels of the enzyme. Another study, out of China and published online in the journal Stress in 2019, linked higher levels of this enzyme in both men and women undergoing fertility treatments with a lower chance of pregnancy.
But these findings should be interpreted with caution. When you look at the actual numbers of women who did and didn’t get pregnant in the first two studies, they weren’t so dramatically different, said Anthony Donoghue, M.S., an adjunct assistant professor of statistics at Columbia University and author of “Statistics and the Media: Foundations in Statistical Thinking through Media Examples.” In the Chinese study, there were larger differences in pregnancy rates but since this study was observational, he said, there could have been other factors influencing the results. “There might be something there, but probably not a whole lot,” Donoghue said, who was not involved with the studies. The authors of the 2014 study also reported that they did not find a link between fertility and cortisol, a hormone released in response to stress; nor did they find links between self-reported stress and pregnancy.
Precisely how stress might reduce fertility is still unknown. Some experts have hypothesized that stress may reduce libido, leading to less frequent sex. Others have suggested that stress may dampen the immune system in a way that is bad for implantation.
A few studies have suggested a link between stress and lower sperm quality, but findings are inconsistent. Authors of one study, which was published in 2014 in Fertility and Sterility, interviewed 193 men between 38 and 49 and analyzed their semen samples. They found that life stress (but not work stress) was associated with reduced sperm concentration and speed, as well as abnormally shaped sperm. A 2010 study of 744 men published in the same journal, however, found that the 166 men who reported at least two instances of life stress had lower sperm concentration, but the same number of normally shaped sperm as those who reported less stress, so their fertility rates may not have been impacted.
Researchers have theorized that stress might reduce sperm concentrations by producing a rush of glucocorticoids, a class of steroid hormones that temper the secretion of testosterone from cells in the testes.
Bruce McEwen, Ph.D., a pioneering stress researcher and a professor and director of the neuroendocrine laboratory at Rockefeller University in New York City, said that while data is lacking, he suspects that chronic stress may dampen fertility indirectly. Stress, for instance, can disrupt sleep, which in turn can throw the circadian rhythm out of whack and upset the normal ebb and flow of hormones. Stress may also create or exacerbate disordered eating — which can lead to irregular or absent periods.
Studying stress can also be complicated because the definition of stress is murky. Is a stressful day at the office the same as the stress of a breakup? And how does one accurately measure this nebulous concept?
A 2015 analysis of 39 studies published between 1978 and 2014 (and which included more than 2,700 men and women seeking fertility treatment in the United States and abroad) found that those who practiced cognitive-behavioral therapy (a type of talk therapy) and mindfulness training were more than twice as likely to get pregnant than the couples who didn’t use such stress-reducing strategies. The results were published in the journal BMJ Open.
Yoon Frederiksen, Ph.D., a lead author of the study and an assistant professor of psychology at Aarhus University in Denmark, said that — as with all the stress and fertility studies to date — hers offers a clue about how stress impacts fertility but is not conclusive. “We really want to know what is happening inside the body,” Dr. Frederiksen said.
According to Dr. Domar, the “biggest myth out there is ‘just relax and you’ll get pregnant.’” But she also maintained that there may be some truth to the idea that stress can influence fertility, in one way or another. “I’m talking out of both sides of my mouth,” she said. “I do believe stress can have an impact and I think if you can reduce depression and anxiety, pregnancy rates go up. I don’t know why but they do.”
As for me, I never tried the Florida rest cure, but I got pregnant anyhow — three times, once with twins. And yet, despite the dearth of data, I practiced deep breathing techniques and yoga during each pregnancy. As is the case with conception, I knew there was no proof that such practices during pregnancy would lead to happier and healthier babies, but I felt they couldn’t hurt. And they certainly made me — and perhaps my babies’ — journey calmer as well.
By Randi Hutter Epstein, M.D. Original: HERE