In vitro fertilization in Sweden: child morbidity including cancer risk.

To study long-term morbidity among children conceived by IVF. A register study in Sweden of IVF infants compared with all infants born. National health registers. More than 16,000 children born after IVF (30% of them after intracytoplasmic sperm injection) were studied with national health registers. Total number of days in hospital care at different ages, hospitalization for specific diagnoses, childhood cancer. An overuse of hospital care was found among IVF children up to 6 years of age, which was partly explained by maternal characteristics. Discharge diagnoses indicating brain damage (mental retardation, cerebral palsy, epilepsy, behavioral problems) occurred in excess and seemed to be completely explained by preterm births. In addition, other discharge diagnoses were overrepresented, some of them linked to preterm birth. There were 29 children with cancer (21 expected); 5 of them had Langerhan's histiocytosis. Long-term morbidity among children conceived by IVF is higher than among naturally conceived infants. This was partly explained by an excess of preterm and multiple births but might also mirror different parental attitudes toward medical care for their children. No general increase in cancer risk was seen, but unexpectedly many children with histiocytosis were noted.