The female body attempts to balance its resources between essential maintenance and reproduction, but environmental stressors can overwork the immune system and lessen the resources available for conception. That's according to new research by scientists the University of Illinois, whose work has been published in the American Journal of Human Biology.
The study participants were a group of healthy, premenopausal, European women. The researchers collected the women's urine and saliva samples and measured salivary ovarian hormone levels daily over one menstrual cycle. They also tested urine samples for levels of C-reactive protein (CRP), a commonly used marker of inflammation.
"Depending on the other factors that you look at alongside it, CRP can tell you about immune function or it can tell you about psychosocial stress, because CRP has been correlated to both of those things in other populations," researcher Kathryn Clancy explained. Her team observed a negative relationship between CRP and progesterone - in women with high CRP, progesterone was low.
Clancy said it is too early to tell whether these correlational relationships indicate a causal relationship in which inflammation suppresses ovarian hormones. However, she believes that there are two possible pathways that explain these results.
"One is that there is an internal mechanism, and this local inflammation drives higher levels of CRP, and that is what's correlating with the lower progesterone," she said. "The other possibility is that there is an external stressor like psychosocial or immune stress driving allocation to maintenance effort, which in turn is suppressing ovarian hormones."
Clancy believes that her research will help women understand their bodies better. "From an anthropological perspective, these trade-offs are really important because they help us understand the timing of different life events: Why does someone hit puberty when they do, why do they begin reproducing when they do, why do they space babies the way they do?" Clancy said. "It's really interesting to see the interplay between a person's intentions about when and why to have children, and then their own body's allocations to reproduction or not."
Discuss this article in our forum
Subfertility new culprit in impaired neurological development
Mind/body program boosts IVF chances
Antidepressant meds may compromise male fertility
Stress and Infertility
Source: University of Illinois