"Almost 50,000 children are now born worldwide every year after IVF [in vitro fertilization], yet the effects of IVF on long-term health of infants are unknown," state the authors of a Swedish study of the neurological effects of in vitro fertilization published in The Lancet.
Noting some of the known short-term negative consequences of IVF, the researchers continue: "Numerous studies have dealt with the short-term outcome of IVF--i.e., number of pregnancies achieved, multiple pregnancies, infants born, infant mortality, and different malformations. Thus, rates of prematurity, low birthweight, and the children's need for neonatal intensive care have been reported. However, studies on the long-term outcome, with focus on neurological sequelae of children born after IVF are rare."
As a result, medical professionals in Sweden set forth to conduct a study including the cooperation of the Swedish Paediatric Association, the Swedish Society for Obstetrics and Gynaecology, and the National Board of Health and Welfare, ultimately collecting data on all children born between 1982, when the first Swedish child born as a result of IVF was delivered, and December 31, 1995: "4353 women had 5680 infants (3228 singletons, 2060 twins, 367 triplets, and 25 quadruplets) after IVF between 1982 and Dec 31, 1995." Today, children conceived via IVF constitute 2 percent of all infants born in Sweden.
The Swedish researchers found that, in general, children born as a result of in vitro fertilization were almost twice more likely to need neurological therapy than naturally conceived children (odds ratio 1.7, 95% CI 1.3-2.2).
In particular, the most common neurological diagnosis was cerebral palsy, for which, children conceived using IVF were 3.7 times more likely than naturally conceived children to have cerebral palsy, (95% CI 2.0-6.6). Even for singletons, children born subsequent to IVF were almost three times more likely to be diagnosed with cerebral palsy (odds ratio 2.8, 95% CI 1.3-5.8). The researchers add: "Although low birthweight, low gestational age, and male sex were strong risk factors, IVF independently contributed to risk of development of cerebral palsy."
The risk for suspected developmental delay, the second most common neurological diagnosis, "was increased four-fold (1.9-8.3) in children born after IVF," compared to naturally conceived controls. Furthermore, "When singletons were studied separately, this risk was reduced, but it was still double that seen in controls," (odds ratio 2.0, 95% CI 0.7-5.4).
While the authors point out that, "[w]ith respect to congenital malformations, mental retardation, chromosomal aberrations, and behavioural disorders, we saw no differences between children born after IVF and those born after a natural conception," the prevalence and seriousness of the neurological problems that are linked to IVF-cerebral palsy and developmental delay, among others-cast a dark pall over the continuing practice of in vitro fertilization.