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.
The free radical theory of aging (FRTA) states that organisms age because cells accumulate free radical damage over time.A free radical is any atom or molecule that has a single unpaired electron in an outer shell.While a few free radicals such as melanin are not chemically reactive, most biologically-relevant free radicals are highly reactive. free radical is any atom or molecule that has a single unpaired electron in an outer shell. While a few free radicals such as melanin are not chemically reactive, most biologically-relevant free radicals are highly reactive.