Decreased fertility among female childhood cancer survivors who received 22-27 Gy hypothalamic/pituitary irradiation: a report from the Childhood Cancer Survivor Study

Objective: To evaluate the effect of hypothalamic/pituitary radiation (HPT RT) dose on the occurrence of first pregnancy. Design: Retrospective cohort study of childhood cancer 5-year survivors (CCS) diagnosed between 1970 and 1986 before 21 years of age at one of 26 North American pediatric cancer treatment centers. Setting: Self-administered questionnaire. Patient(s): A total of 3,619 female CCS who participated in the Childhood Cancer Survivor Study and received no or scatter (<= 0.1 Gy) radiation to the ovaries and 2,081 female siblings (Sibs) of the participants. Intervention(s): None. Main Outcome Measure(s): Self-reported pregnancy events. Result(s): As a group, CCS were as likely to report being pregnant as Sibs (hazard ratio 1.07, 95% confidence interval 0.97-1.19). Multivariable models showed a significant decrease in the risk of pregnancy with HPT RT doses >= 22 Gy compared with those CCS receiving no HPT RT. Conclusion(s): These results support the hypothesis that exposures of 22-27 Gy HPT RT may be a contributing factor to infertility among female CCS. (Fertil Steril (R) 2011; 95: 1922-7. (C)2011 by American Society for Reproductive Medicine.)