We are reviewing information concerning to the role of interleukins (ILs) in labor and pregnancy; these substances produce the ignition of the arachidonic acid/prostaglandins cascade to induce labor, this process could be also activated by bacterial lipopolysaccharides in this case we could have preterm labor. The activity and production of IL-2 normally is inhibited, if it does not happen an abortion could result. IL-3 and stimulatory growth factors (SGFs) are implicated in the growth and development of the pregnancy, the alteration in the production of this IL could produce intrauterine growth retardation, both of this ILs are acting in the maternal fetal interface. We consider very important that the gynecologists and obstetricians should have more information about ILs related to normal and complicated pregnancy.