Infertility is a growing problem in the developed world, but why more and more couples are unable to conceive is not always clear. Increasing childbearing age and complex effects of our environment are likely to blame, and so can be the overall hectic lives that many of us lead.
Quite naturally, stress can have a negative effect on the libido – but it has been linked to delayed pregnancy success in couples highly motivated to conceive, and even extreme reproductive system dysfunction in some cases. But what may be the molecular reasons behind lasting effects of stress on fertility?
A joint team of researchers at University of California and the Canadian Institute for Advanced Research have set out to answer this very question – their findings were published last week on eLife. According to their study, a single hypothalamic peptide RFRP3, which activated under stress, could be to blame for lasting negative effects on infertility in healthy females.
RFRP3 is a hypothalamic hormone common across mammals, including rodents, non-human primates and humans. While its precise mode of action is unknown, it is suspected to influence reproductive function by inhibiting synthesis and release of sex steroids: gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion and follicle stimulating hormone (FSH).
Curiously, RFRP3 activity remains high for a while after the stressor is removed, which may explain lasting effects that stressful events have on lowered conception rates.
By silencing RFRP3, the researchers were able to preserve all aspects of reproductive health in post-stress mice, thus suggesting a single molecular target that could help alleviate a range of stress-induced fertility problems.
“It is possible that manipulation of RFRP3 signaling in humans may relieve stress-related reproductive dysfunction, including decreased sex drive, impaired fertility, and increased miscarriages”, the researchers said.
Currently, as many as 63–80% of couples under 30 years of age are unable to conceive within 3 months of trying and 15% remain disappointed within 1 year. Successful manipulation of molecular pathways involved in infertility could help to reduce these numbers significantly.
Aside from human infertility, the findings may have ecological implications too – if the action of RFRP3 is universal across species, knowledge of its mechanism of action could improve breeding practices for animals bred in captivity, which experience significant reproductive disadvantage linked to stress.
Written by Eglė Marija Ramanauskaitė