Water is a substance essential for life. It creates the environment of our body, keeps it's homeostasis, enables every biochemical reaction and metabolic processes in human organism. Maternal hydratation is essential for homeostasis of two organisms and drinking water influences the amniotic fluid volume, fetal well-being and removes toxic metabolic products. The chemical contaminants of drinking water and products of it's chlorination and ozonization could be responsible for spontaneous abortion, birth defects and perinatal complications.