Human spaceflight: to infertility and beyond


  • Walter D. Cardona Maya Reproduction Group, Department of Microbiology and Parasitology, Medical School, University of Antioquia, Antioquia, Colombia
  • Stefan S. du Plessis Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa



Not Applicable


Garrett-Bakelman FE et al, demonstrated a spectrum of molecular and physiological changes attributed to spaceflight in their recently published “NASA Twins Study”.1 During his 340 days in space onboard the International Space Station (ISS), one of a pair of monozygotic twins was not only challenged by noise, isolation, hypoxia, and alterations in the circadian rhythm, but more importantly the exposure to ionizing radiation (IR) and microgravity. Terrestrials are subjected constantly to surface gravity and most if not all physiological processes have adapted accordingly. It is therefore easy to envisage that weightlessness can have consequences for space travellers.2


Garrett-Bakelman FE, Darshi M, Green SJ, Gur RC, Lin L, Macias BR, et al. The NASA twins study: amultidimensional analysis of a year-long human spaceflight. Science. 2019;364:6436.

Lobrich M, Jeggo PA. Hazards of human spaceflight. Science. 2019;364(6436):127-8.

Wakayama S, Kamada Y, Yamanaka K, Kohda T, Suzuki H, Shimazu T, et al. Healthy offspring from freeze-dried mouse spermatozoa held on the International Space Station for 9 months. Proc Natl Acad Sci U S A. 2017;114(23):5988-93.

Ikeuchi T, Sasaki S, Umemoto Y, Kubota Y, Kubota H, Kaneko T, et al. Human sperm motility in a microgravity environment. Reprod Med Biol. 2005;4(2):161-8.

Ding Y, Tang J, Zou J, She R, Wang Y, Yue Z, et al. The effect of microgravity on tissue structure and function of rat testis. Braz J Med Biol Res. 2011;44(12):1243-50.

Masini MA, Albi E, Barmo C, Bonfiglio T, Bruni L, Canesi L, et al. The impact of long-term exposure to space environment on adult mammalian organisms: a study on mouse thyroid and testis. PLoS One. 2012;7(4):e35418.

Merrill AH, Wang E, Mullins RE, Grindeland RE, Popova IA. Analyses of plasma for metabolic and hormonal changes in rats flown aboard COSMOS 2044. J Appl Physiol. 1992;73(2 Suppl):132S-5S.

Tash JS, Johnson DC, Enders GC. Long-term (6-wk) hindlimb suspension inhibits spermatogenesis in adult male rats. J Appl Physiol. 2002;92(3):1191-8.

Fedorova NL. Spermatogenesis in the dogs ugolyok and veterok after the kosmos-110 spaceflight. Kosm Biol Med. 1967;1:28-31.

Philpott DE, Sapp W, Williams C, Stevenson J, Black S, Corbett R. Reduction of the spermatogonial population in rat testes flown on Space Lab-3. Physiol. 1985;28(6 Suppl):S211-2.

Sapp WJ, Philpott DE, Williams CS, Kato K, Stevenson J, Vasquez M, et al. Effects of spaceflight on the spermatogonial population of rat seminiferous epithelium. FASEB J. 1990;4(1):101-4.

Darmishonnejad Z, Tavalaee M, Izadi T, Tanhaei S, Nasr-Esfahani MH. Evaluation of sperm telomere length in infertile men with failed/low fertilization after intracytoplasmic sperm injection. Reprod Biomed Online. 2019;38(4):579-87.






Letter to the Editor