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.
(Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)