Maternal illnesses during pregnancy and the risk of childhood cancer: A medical‐record based analysis (UKCCS)

Often relying on mother's recollections of past events, the possible relationship between maternal illness in pregnancy and risk of malignancy in their offspring has long been a focus of research. Free from recall bias, this study of childhood cancer (0-14 years) examined these associations using data abstracted from mothers' primary-care (1623 cases, 2521 controls) and obstetric (2721 cases, 5169 controls) records. Maternal infections and other illnesses in pregnancy were examined for any possible associations with childhood leukaemia, lymphoma, CNS or embryonal tumours using pooled information from the two medical record sources (2885 cases and 5499 controls), accounting for potential confounders. Maternal anaemia was associated with childhood acute myeloid leukaemia (AML) (odds ratio, OR = 2.07, 95%CI [1.40-3.08]). Anaemia during pregnancy was also recorded more frequently in the notes of mothers of children with medulloblastoma, retinoblastoma and embryonal rhabdomyosarcoma: ORs 2.36 [1.36-4.11], 1.83 [1.01-3.33] and 2.91 [1.64-5.16] respectively. Other associations included urinary tract infections (UTIs) and non-Hodgkin lymphoma (NHL); preeclampsia and NHL; and polyhydramnios with both AML and NHL. No evidence was found to suggest that influenza during pregnancy impacted on childhood leukaemia risk. In conclusion, our findings are supportive of an association between maternal anaemia in pregnancy and childhood AML, and maternal anaemia and embryonal tumours; underscoring the need for further research exploring the potential causes and roles of iron and vitamin deficiencies. Due to small numbers and lack of corroborative evidence, the associations observed for UTIs, preeclampsia, and polyhydramnios must be treated cautiously.