In vitro fertilization and childhood cancers: Review

Abstract

Assisted fertilization techniques (AFT) are commonly used in the treatment of infertility. Although there are many reports on the short term outcomes of these techniques such as perinatal mortality, multiple pregnancy, low birt weight and congenital maformations, data on long term effects are limited. Cancers of the childhood are relatively rare with unknown etiology. Because of their onset early in life, exposure to environmental factors either in utero or after birth may be less determining than the cancers developing in adults. Theoretically, assisted fertilization techniques might lead to carcinogenetic alterations. In vitro fertilization has the potential to alter oocyte and embryonic cell physiology and change gene expression in the embriyo. Repeated exposure to hormonal effects, alterations in gene expression and epigenetic modifications are reported to play a potential role in the association between cancers of the childhood and assisted fertilization techniques. Childhood cancers developing in children born after assisted fertilization techniques have been reported in the literature. Although a high risk has been reported for the development of childhood cancers in children born after assisted fertilization techniques has been reported in some case control studies, there are contradictory results reporting no increase in this risk. Cohort studies demonstrate no difference in the incidence of childhood cancers in children born after assisted fertilization techniques and after natural pregnancy. Although the results of the cohort studies are more reliable and stronger than the results of case reports and case control studies, it should be kept in mind that follow-up periods and number of control cases might not be sufficient to draw reliable conclusions. Thus, cohort studies with longer follow-up periods and greater number of participants are mandatory. Assisted reproductive techniques are commonly used in our country, and multicenter cohort studies need to be planned in order to evaluate the risk of cancer development in children born with the assistance of these techniques. © 2011 by Türkiye Klinikleri.