Donating eggs for a childless woman may impair your own fertility.

I donated eggs to friends... now I've been left infertile - Daily Mail

Extract:

"A woman who gave her eggs to help two childless friends fears she has been left infertile by her act of kindness.

Donna Stickels, 26, revealed her personal ordeal to warn other women about the potential dangers of egg donation."

Fertility can sometimes be improved by reducing salt intake. - See http://www.wildeaboutsteroids.co.uk/conditions.html