Menopause is uniquely human
This is my first post of the new year, as I have returned to work :((. Oh well….I hope everything went well for all of you, and you have a hormonally healthy 2014. Most women find going through menopause a shock, as it is hard to understand why this is happening. We really don’t know.
Human women are the only animals who go through menopause, with most other primates remaining fertile until death.
The reason of menopause as an evolutionary trait is not known but research suggests the female reproductive system hasn’t adjusted to increasing human lifespan.
Researchers hope to examine the role of grandparents in primate development to see if this may have caused the evolutionary anomaly.
Reproductive aging patterns in primates reveal that humans are distinct
- Susan C. Albertsa,b,1,
- Jeanne Altmannb,c,1,
- Diane K. Brockmand,
- Marina Cordse,
- Linda M. Fediganf,
- Anne Puseyg,
- Tara S. Stoinskih,
- Karen B. Strieri,
- William F. Morrisa,j, and
- Anne M. Bronikowskik
Contributed by Jeanne Altmann, June 25, 2013 (sent for review April 17, 2013)
Women rarely give birth after ∼45 y of age, and they experience the cessation of reproductive cycles, menopause, at ∼50 y of age after a fertility decline lasting almost two decades. Such reproductive senescence in mid-lifespan is an evolutionary puzzle of enduring interest because it should be inherently disadvantageous. Furthermore, comparative data on reproductive senescence from other primates, or indeed other mammals, remains relatively rare. Here we carried out a unique detailed comparative study of reproductive senescence in seven species of nonhuman primates in natural populations, using long-term, individual-based data, and compared them to a population of humans experiencing natural fertility and mortality. In four of seven primate species we found that reproductive senescence occurred before death only in a small minority of individuals. In three primate species we found evidence of reproductive senescence that accelerated throughout adulthood; however, its initial rate was much lower than mortality, so that relatively few individuals experienced reproductive senescence before death. In contrast, the human population showed the predicted and well-known pattern in which reproductive senescence occurred before death for many women and its rate accelerated throughout adulthood. These results provide strong support for the hypothesis that reproductive senescence in midlife, although apparent in natural-fertility, natural-mortality populations of humans, is generally absent in other primates living in such populations.
Author contributions: K.B.S. and S.C.A. organized the Working Group that performed this research; S.C.A., J.A., D.K.B., M.C., L.M.F., A.P., T.S.S., K.B.S., W.F.M., and A.M.B. designed research; S.C.A., J.A., D.K.B., M.C., L.M.F., A.P., T.S.S., and K.B.S. performed research; S.C.A. and A.M.B. analyzed data; and S.C.A., J.A., D.K.B., M.C., L.M.F., A.P., T.S.S., K.B.S., W.F.M., and A.M.B. wrote the paper.
The authors declare no conflict of interest.
Data deposition: Data underlying these analyses have been deposited in the Dryad Data Repository, datadryad.org, (10.5061/dryad.m327n).
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1311857110/-/DCSupplemental.
Freely available online through the PNAS open access option.