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Analysis of information obtained in an inter-regional epidemiological study by interviewing the parents of 555 children with malignancy diagnosed between 1980 to 1983 and the parents of 1110 control children did not reveal any significant association between exposure to ultrasound examination in pregnancy and risk of childhood cancer.

The Inter-Regional Epidemiological Study of Childhood Cancer (IRESCC) was established to investigate the role of possible aetiological factors in childhood cancer, with particular emphasis on environmental exposures to the foetus and family history of certain diseases including cancer. Incident cases occurring in three Health Service regions (the West Midlands, Yorkshire and North Western) were matched for age and sex with two sets of control children. A total of 555 cases and 1110 controls were entered into the study. The parents of each index child were interviewed with respect to events during the relevant pregnancy, occupation, smoking habits, and past medical history of themselves, the child's siblings and other relatives. Ninety-three per cent of case parents approached agreed to be interviewed, and approximately 90% of controls were ranked first or second on the control selection lists. After the interview information was verified by reference to antenatal and other medical records. Obstetric and general practitioner records were abstracted for approximately 90% of cases and controls. Information derived from the interview and that from medical records was coded separately. The data collected by each region have been pooled and case-control comparisons of potential aetiological factors will be carried out, using matched triplet analyses.

Attention has recently focused on the possible teratogenic effects of the combination antiemetic doxylamine succinate, dicyclomine hydrochloride and pyridoxine hydrochloride (Debendox/Bendectin) prescribed to pregnant women. The Inter-Regional Epidemiological Study of Childhood Cancer (IRESCC), a case-control investigation has analysed data derived from interview reports and medical records of 555 mothers of children (under 15 years) with cancer and 1110 mothers of matched control children. Separate analyses of interview reports and medical records both suggested that antiemetic ingestion during the index pregnancy does not increase the risk of developing childhood malignant disease in the exposed foetus. No dose-response relationship was evident. The lack of any significant relative risks held good for diagnostic sub-groups and when the trimester of ingestion was considered. Our results suggest that antimetics of this type are unlikely to be transplacental carcinogens.

In 1980-1983 members of IRESCC interviewed parents of 555 children with newly diagnosed cancer on topics of possible aetiological significance. Identical questions were asked of the parents of 1100 control children chosen from hospital admissions and general practitioner lists. Medical information was confirmed whenever possible by cross-checking with NHS records. Data for the 41 children with germ cell tumours and their 82 controls are reported here. The cases had more major congenital malformations than controls, including one neural tube defect. More case than control mothers and fathers reported occupational exposure to chemicals. Nine close relatives of cases had multiple primary tumours, which were often benign or of low-grade malignancy, compared with 1 hospital control and 3 general practitioner control relatives. Cases and controls differed with respect to birth weight and paternal age. No case-control differences were shown for: birth rank, maternal age, chronic illnesses and smoking, mothers' reproductive histories and oral contraceptive usage. In index pregnancies there were no case-control differences for maternal illness, infections, alcohol intake and X-ray and ultrasound exposure. There was no difference between cases and controls for the frequency of twinning the families.

The inter-regional epidemiological study of childhood cancer analysed data on 234 children diagnosed with leukaemia or lymphoma and 468 controls matched for age and sex. A wide range of potential risk factors was examined, including prenatal exposure to x rays, maternal drug ingestion and smoking, child's medical history, and parental medical conditions and occupation. Calculations were completed for leukaemia or lymphoma and diagnostic subgroups, as defined by laboratory confirmed cell type. In utero exposure to narcotic analgesics was weakly associated with leukaemia or lymphoma but no other antenatal factors gave significant risks. New associations were identified for skin diseases in both parents and congenital abnormalities in the mothers of children with leukaemia. For past medical conditions in the child, viral disease occurring under 6 months of age increased the risk for acute lymphoblastic leukaemia. Fewer children in the leukaemia or lymphoma group had been immunised compared with the control groups. Case children diagnosed over the age of 9 years were more likely than controls to have had four or more previous episodes of illness. Overall, these results indicate that prenatal factors may be less important than postnatal or genetic influences in the development of leukaemia or lymphoma in children.