If you have allergies, pregnancy can make your symptoms worse. But you're right to worry about taking allergy medicine during pregnancy. Pregnant women shouldn't take some allergy drugs. Certain antihistamines, however, are safe.
free radical. (chemistry). An atom or a diatomic or polyatomic molecule which possesses one unpaired electron. Also known as a radical.ree radical. in chemistry, a molecule or atom that contains an unpaired electron but is neither positively nor negatively charged. Free radicals are usually highly reactive and unstable.
A free radical is any atom or molecule that has 1 or more unpaired electrons and is therefore highly reactive, seeking to acquire electrons from other substances. Free radicals are normally scavenged from tissues by the antioxidant enzymes superoxide dismutase and glutathione peroxidase.