Female reproductive dysfunction and transgenerational consequences following prolonged spaceflight exposure.

Spaceflight presents unique gravitational, radiation, and isolation hazards for human exploration of the Moon, Mars, and beyond, yet its impact on the female reproductive system and successive generations has been largely unassessed. In the NASA Rodent Research 20 mission, we examined the impact of a 42-d spaceflight on the female reproductive axis including ovulatory capacity, implantation rate, and fecundity as well as behavioral, metabolic, and functional outcomes in F1 and F2 offspring. Females bred 5 d after return to Earth became pregnant but only exhibited a slight decline in fecundity compared to ground controls. In contrast, F1 offspring from spaceflight dams exhibited marked growth, functional, and behavioral differences compared to F1 offspring from control dams. Moreover, F1 female offspring from spaceflight dams exhibited decreased ovarian reserves as evidenced by reduced anti-Mullerian hormone levels early in life (21 d of age) and premature ovarian failure or an early loss in fertility, as indicated by reduced numbers of litters and total number of pups born to females over a 9-mo period. Strikingly, transgenerational metabolic and reproductive disturbances were also observed in F2 pups of spaceflight granddams, including persistent reductions in ovarian reserve, suggesting germline-level effects. Together these findings reveal significant short- and long-term impacts of spaceflight on the female reproductive system and on their offspring across generations, demonstrating biological transmission of reproductive vulnerability following maternal spaceflight exposure, and raising concerns for space travelers and colonization missions.