- © 2008 Canadian Medical Association
I read with interest the cost-utility analysis of abolishing the law of gravity by Claude Cyr and Luc Lanthier.1 Their conclusion that microgravity might be the solution to the health care crisis in Canada is intriguing.
As the International Space Station moves us closer to the possibility of colonizing space, it is becoming increasingly important to understand the effects of altered gravity on mammalian reproductive physiology. There is evidence that hypo- and hyper-gravity induce changes in male and female reproductive processes.2 Findings from studies using a variety of experimental conditions to simulate hypogravity raise questions about whether reproduction is possible when gravity is reduced.
Studies using the Holton hindlimb suspension model, which provides a practical way to simulate the major physiologic effects of hypogravity, are providing evidence that hypogravity might exert pronounced effects on male reproductive processes and reduce the rate of implantation during early pregnancy in rats. Moreover, the cardiovascular deconditioning, bone demineralization and decrease in red blood cell concentration associated with hypogravity might affect the ability of female rats to sustain their pregnancies. Similar findings from experiments during space flights raise questions about whether early pregnancy can be sustained in humans when gravity is reduced.2 Additional research is needed to fill in the gaps in our knowledge about reproductive physiology under conditions of hypo- and micro-gravity.
Footnotes
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Competing interests: None declared.