In Vitro Babies at Risk for Brain Disorders
They found that the most frequent diagnoses were cerebral palsy, developmental delay, congenital malformation, mental retardation, chromosomal aberration, and behavioral disorders.
But when they took a closer look at 2,060 twins in this group, they found that IVF children -- especially twins -- were nearly three times more likely to have cerebral palsy than children in the general population, says Stromberg.
IVF children also had a four-fold increased risk of developmental delay.
Other factors, like the mother's age, did not seem to increase risk for neurological problems, says Stromberg.
"The results of this study are important," writes David L. Healy, an obstetrics/gynecology professor at Monash University in Melbourne, Victoria, in an accompanying editorial. "If the high prevalence is a true result, then the question is whether the IVF process is deficient in some way."
"The high prevalence of cerebral palsy ... seems to be due to the high frequency of twin and higher multiple pregnancies," writes Healy. "Senior figures in the U.S. have recently pleaded for a reduction of twin and higher-order multiple pregnancies to minimize the short-term and long-term damage to babies and mothers."
While it does indicate a pattern, Stromberg's paper does leave unanswered questions: whether the IVF was natural-cycle or stimulated cycle or whether gamete intrafallopian transfer, fresh or frozen embryos, or intracytoplasmic sperm injection were involved, Healy points out.
Nevertheless, the study points to a "need for a shift from multiple to single embryo transfer," Healy says. He, like Brill, calls for more research. "What an infertile couple really needs to know, though, is not their relative risk of having a child with cerebral palsy should they have an IVF baby, but their absolute risk -- which remains to be established."