Recent childbirth is an adverse prognostic factor in breast cancer and melanoma, but not in Hodgkin lymphoma

Background: The relationship between gestation, childbirth and cancer prognosis is unknown for most cancers (e.g. Hodgkin lymphoma), whereas a body of evidence exists for melanoma and breast cancer. Methods: The national cancer registration and hospital discharge data for women in England (1998-2007) were linked, and the records for Hodgkin lymphoma, melanoma and breast can- cer were indexed as to whether women had delivered a child in separate time periods prior to their cancer diagnosis. Survival analyses were conducted in order to characterise prognosis in relation to childbirth, with statistical adjustment for age and (where possible) stage. Findings: For melanoma and breast cancer, survival was strongly reduced in women who gave birth in the year prior to cancer diagnosis. The age-adjusted hazard ratios (HR) with 95% con- fidence intervals (CI) were 2.06 (1.42-3.01) for melanoma and 1.84 (1.64-2.06) for breast can- cer. The associations were only slightly attenuated by further adjustment for tumour stage. For breast cancer, the excess death rate in women with a recent childbirth peaked at 2 years and remained elevated for 6 to 8 years. Previous childbirth had no overall effect on the out- come of Hodgkin lymphoma.