Prescription drug use during pregnancy and risk of childhood cancer - is there an association?

In economically developed countries up to 90% of women are prescribed medications, including vitamins and supplements, during pregnancy. Whilst a number of adverse health outcomes in their offspring have been related to prescription drug use, associations with childhood cancer are less clear and most investigations have been reliant on maternal self-report. With a view to providing new insight we investigated maternal prescription drug use and risk of childhood cancer primary care medical records collected as part of the United Kingdom Childhood Cancer Study, a national population-based case-control study conducted between 1991 and 1996. There was evidence that mothers of children with acute lymphoblastic leukaemia (OR 1.36, 95% CI 1.14-1.63), medulloblastoma (OR 1.79, 95% CI 1.00-3.22) and Wilms tumour (OR 1.79; 95% CI 1.05-3.04) were more likely to have been prescribed iron when compared to mothers of controls. In addition, systemic anti-infectives were positively associated with acute myeloid leukaemia (OR 1.58, 95% CI: 1.05-2.38) and rhabdomyosarcoma (OR 1.80, 95% CI 1.03-3.16), and analgesic use (NO2B) was positively associated with Hodgkin lymphoma (OR 5.02, 95% CI 2.16-11.82) and neuroblastoma (OR 1.99, 95% CI 1.07-3.69). Whilst our findings suggest that maternal use of antibiotics, iron, and nervous system drugs during pregnancy may be associated with some childhood cancer subtypes these associations need to be confirmed elsewhere. Unravelling the mechanisms that may underpin these associations is complex and research is needed to determine whether they are directly related to the drugs themselves, or the illnesses for which they were prescribed.