Congenital malformations in offspring of women with a history of malignancy

Background Survival after malignancy has increased and the question of risks, including risk for congenital malformations for the offspring of these women has become important. Data on congenital malformations in such offspring are limited. Methods We compared congenital malformation in offspring, born 1994 to 2011 of women with a history of malignancy (at least 1 year before delivery) with all other offspring. Adjustment for confounders was mainly made by Mantel-Haenszel methodology. Data were obtained by linkage between Swedish national health registers. Results We identified 71,954 (4.1%) infants with congenital malformation, of which 47,081 (2.7%) were relatively severe (roughly corresponding to major malformation). Among 7284 infants to women with a history of malignancy 204 relatively severe malformations were found (2.8%; odds ratio [OR] = 1.04; 95% confidence interval [CI], 0.91–1.20). After in vitro fertilization, the risk of a relatively severe malformation was significantly increased in women without a history of malignancy (OR = 1.31; 95% CI, 1.24–1.38) and still more in women with such a history (risk ratio = 1.85; 95% CI, 1.08–2.97). However, there were no significant differences neither, for any malformations (OR = 1.04; 95% CI, 0.92–1.16) nor for relatively severe malformations (OR = 1.04; 95% CI, 0.91–1.20), when comparing offspring only after maternal history of malignancy. Conclusion No general increase in malformation rate was found in infants born to women with a history of malignancy. A previously known increased risk after in vitro fertilization was verified and it is possible that this risk is further augmented among infants born of women with a history of malignancy. Birth Defects Research (Part A), 2016. © 2016 Wiley Periodicals, Inc.