A Swedish study in this week’s issue of THE LANCET suggests that children born after in-vitro fertilisation (IVF) could be at an increased risk of developing neurological problems, especially cerebral palsy. The authors conclude that a reduction in this risk is possible if only one embryo is transferred during IVF, reducing the likelihood of twin pregnancies and low-birthweight children.
There are no population-based studies with sufficient follow-up on the risk of neurological disorders in children born after IVF. Bo Strömberg and colleagues compared the frequency of such problems in IVF-born children with those in children conceived naturally.
In a retrospective population-based study, the investigators compared development of neurological problems in 5680 children born after IVF with 11,360 matched controls. For 2060 twins born after IVF, a second set of 4120 control children (who were all twins) were studied. IVF children were around three times more likely to have cerebral palsy than children from the general population (IVF multiple-births and IVF singletons had increased relative risk profiles of 3.7 and 2.8, respectively). Suspected developmental delay was increased four-fold in children born after IVF. With regard to all neurological problems, there was no increased risk for IVF twins compared with twins in the general population. Increased maternal age was not a risk factor for neurological problems among IVF children.
Bo Strömberg comments: “Our study suggests that children born after IVF have an increased risk of developing neurological problems, especially cerebral palsy. These risks are largely due to the high frequency of twin pregnancies, low birthweight, and prematurity among babies born after IVF. To limit these risks, we recommend that only one embryo should be transferred during IVF.”
In an accompanying Commentary (p 459), David Healy and Kerryn Saunders from Monash University, Melbourne, Australia, conclude: “The study by Strömberg and colleagues is valuable, but does not remove the need for clinical studies. It certainly heightens the need for a shift from multiple to single embryo transfer. 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. The answer is out there somewhere.”
Contact: Dr Bo Strömberg, Associate Professor in Paediatric Neurology, Uppsala University Children's Hospital, Department of Women's & Children's Health, Akademiska Sjukhuset, SE-751 85, Uppsala, Sweden; T) + 46 18 611 0000 (ask for bleep); F) +46 18 611 5853; E) Bo.Stromberg@kbh.uu.se
Dr David Healy, Department of Obstetrics and Gynaecology and Department of Paediatrics, Monash University, Melbourne, Victoria 3168, Australia; E) david.healy@med.monash.edu.au
Journal
The Lancet