ABSTRACT
Since the birth of Louise Brown in 1978, in vitro fertilization (IVF) has become a widely used treatment for infertile couples and has spread gradually throughout the Western world. Even though great concern was voiced at the introduction of IVF, a formal and systematic evaluation of the outcome of this high-tech procedure was not carried out and relatively few studies on the children were under-taken. Gradually, IVF became accepted as a safe technique, mostly on the basis of the information in registries with retrospectively collected data1-3. One early study mentioned a statistically relevant increase in two types of birth defect in IVF as compared to the general population: neural tube defects and transposition of the great vessels4. This report was not confirmed by other studies in the 1980s. However, in one later Swedish retrospective cohort study on 5856 IVF babies5, the risk of neural tube defects (hydrocephaly risk ratio 5.7, anencephaly risk ratio 12.9) and of esophageal atresia (risk ratio 3.9) was significantly higher in the IVF group than in the control group. In another Swedish study, all 9111 children born in Sweden after IVF (1982-97) were compared to a population-based control group6. An excess of congenital malformations was found, which disappeared when confounders such as year of birth, maternal age, parity and period of unwarranted childlessness were taken into account. A three-fold risk was observed in the incidence of some specific conditions: neural tube defect, alimentary atresia and omphalocele. In one recent study on 837 IVF children (and 301 children born after intracytoplasmic sperm injection; ICSI) the odds ratio for a major birth defect in IVF singletons at the age of 1 year was 2.0 (95% confidence interval 1.5-2.9) after adjustment for maternal age, parity, sex of the infant and correlation between siblings7. This study led to a new debate on the risk of congenital anomalies after IVF.
