title: Radiation effects on development.
abstract: It has been widely reported that prenatal exposure to ionizing radiation can interfere with embryonic and fetal development, depending on dose and gestational age in which exposure occurs. According to several studies on animal models, different well-defined stages during prenatal life can be distinguished in relation to teratogenic effects. During the preimplantation stage, elevated doses of radiation can result in abortion, while lower doses may produce genomic damage that is usually repaired. On the other hand, during the organogenesis stage in mice (embryonic day 6.5 [E6.5] to E13.5), irradiation is associated with increased incidence of malformation and intrauterine growth restriction (IUGR). Later exposure is linked to brain damage. Doses used in animal studies are generally higher than those used for diagnostic procedures in humans. Usually, radiation exposure to diagnostic range (<0.05 Gy = 5 rads) is not associated with an increased risk of congenital anomalies. In human studies, elevated doses produce adverse outcomes, depending on stage of development, as in animal studies. Blastogenesis (up to two weeks) is associated with failure to implant or no significant health effects. An increased risk of malformation and growth retardation can be observed for two to seven weeks exposure (organogenesis stage), while exposure at later stages (fetogenesis) is mainly associated with brain damage. In this review we focus on the relevance of estimating the cumulative dose of radiation to the fetus and the gestational age in which exposure occurs, to provide appropriate counseling to pregnant women.
authors.affiliation: Telefono Rosso-Teratology Information Service, Department of Obstetrics and Gynecology, Catholic University, Largo Agostino Gemelli 1, Rome, Italy. marcodesantis@rm.unicatt.it
authors.forename: Marco
authors.initials: M
authors.lastname: De Santis
authors.forename: Elena
authors.initials: E
authors.lastname: Cesari
authors.forename: E
authors.initials: E
authors.lastname: Nobili
authors.forename: Gianluca
authors.initials: G
authors.lastname: Straface
authors.forename: Anna Franca
authors.initials: AF
authors.lastname: Cavaliere
authors.forename: Alessandro
authors.initials: A
authors.lastname: Caruso
mesh_terms: D000016:Abnormalities, Radiation-Induced / Q000209:etiology / Q000235:genetics; D000022:Abortion, Spontaneous / Q000209:etiology; D000818:Animals; D002490:Central Nervous System / Q000528:radiation effects; D002657:Child Development / Q000528:radiation effects; D002675:Child, Preschool; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005333:Fetus / Q000528:radiation effects*; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D051379:Mice; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011832:Radiation Injuries / Q000196:embryology; D011833:Radiation Injuries, Experimental / Q000196:embryology