Medical researchers at Hadassah Medical School in Jerusalem studying the effects of liver transplants in mice, found that in 96% of older, pregnant rodents, the liver regenerated within two days. This compared with 82% of young, non-pregnant mice and 46% of older, non-pregnant ones.

http://www.timesofisrael.com/pregnancy-can-boost-health-slow-ageing-israeli-study-finds/