In vitro fertilization (IVF) in Sweden:: Risk for congenital malformations after different IVF methods

BACKGROUND: The possible excess of congenital malformations in infants born after in vitro fertilization (IVF) has been much discussed in the literature, with controversial conclusions. This population based study is aimed at analyzing the presence of congenital malformations in a large group of infants born after IVF and to compare malformation risk both with that of all infants born and according to IVF method used. METHODS: Infants born after IVF during the period 1982-2001 were ascertained from all IVF clinics in Sweden. The presence of congenital malformations was identified from three national health registers: the Swedish Medical Birth Register, the Swedish Registry of Congenital Malformations, and the Swedish Hospital Discharge Register. The IVF children were compared with all children born in Sweden during the same period and recorded in the Swedish Medical Birth Register. RESULTS: Among 16,280 IVF children (30% conceived after intracytoplasmatic sperm injection [ICSI]) a 42% excess of any congenital malformation was found, explainable by parental characteristics and in some cases by the high rate of multiple births. Among these children, 8% had a congenital malformation, and 5% had a relatively severe condition. For neural tube defects, choanal atresia, and alimentary tract atresia, an additional risk increase was seen. There was no difference in malformation rate according to IVF method except for an excess of hypospadias after ICSI. CONCLUSIONS: An increased risk for congenital malformations occurs after IVF, similar for the different IVF techniques used, and mainly a consequence of parental characteristics. A few specific conditions show an extra increase in risk. (c) 2005 Wiley-Liss, Inc.