However, Dr Florence Belva told a news briefing that, in line with previous studies of children conceived using intra-cytoplasmic sperm injection (ICSI), the study showed a slightly higher rate of major congenital malformations. She suggested this could be related to the genetic background of the parents rather than to the ICSI technique.
Dr Belva, a paediatrician and research assistant at the Centre for Medical Genetics, Vrije Universiteit Brussel, Belgium, said: "Since the introduction of ICSI in 1991 concerns remain about its potential risks for the health and future fertility of offspring. Several studies investigated medical outcome from birth up to the age of five years with reassuring findings. This is the first study to look at the health of ICSI children at the age of eight, just before the onset of puberty."
The researchers carried out a detailed physical and neurological examination of 150 ICSI children (76 boys, 74 girls) and compared them with 147 children (76 boys, 71 girls) born without assisted conception. The children were Dutch-speaking, singletons, with at least one European parent, and who were not extremely prematurely born.
Dr Belva said: "Major congenital malformations were defined as those causing functional impairment and/or needing surgical correction; all the rest were minor malformations." Examples of major malformations included dextrocardia (where the apex of the heart points to the right instead of the left), large port wine mark (naevus flammeus), groin hernia, squint and problems associated with the ureter (the tube that carries urine from the kidneys to the bladder). Examples of minor malformations included ear abnormalities, mongoloid eyes and overriding toes.
"We found no important medical problem in either of the two groups we studied. Weight, height, head circumference and Body Mass Index did not differ between the two groups. Ten per cent of ICSI children (15 out of 150) experienced a major congenital malformation compared to 3.3% (5 out of 147) of the spontaneously conceived (SC) children. Minor malformations were found in 24.1% (35 out of 145) ICSI children compared to 17.2% (25 out of 145) SC children."*
The researchers asked another research group in Western Australia to re-assess their data blindly, according to their own coding system. Their results reduced the percentage of major congenital malformations from 10% to 4% amongst the ICSI children, and from 3.3% to 0% amongst the SC children. Minor malformations were reduced from 24.1% to 4.8% in the ICSI children and from 17.2% to 4.8% in the SC children.
"Other results showed little, if any, difference between ICSI and SC children, physically or neurologically. ICSI children were not more likely to require additional therapy, to have had surgery or to be hospitalised. There was no greater medication intake or more chronic disease among the ICSI children," said Dr Belva.
"Overall, the findings from the clinical examinations at the age of eight are reassuring. There were no clinically important differences between ICSI and SC children. Major congenital malformations appeared to be more frequent in the ICSI group, even after the re-classification exercise; however, most were corrected by minor surgery.
"We should remember that malformations occur also in the 'normal' population and can be caused by genetic inheritance, the environment, disease or other causes. If one of the parents has a malformation, they could pass it on to their offspring. We do not think the ICSI technique itself is the cause of the malformations, but is more likely to be related to the parental genetic background and the infertility history of the couple.
"The overall general health of eight-year-old singleton ICSI children who were not extremely prematurely born seems satisfactory, but more children should be examined. This is a small study and the children represent the first wave born after the introduction of the ICSI technique in 1991. To include more children of this age, multi-centre studies are necessary.
"We are planning long-term follow-up at later milestones in life. We are currently assessing these same children at the age of 10, and we need to check them again later in puberty and afterwards at reproductive age.
"The current clinical examinations at this stage of their lives have revealed no major problems; almost all major malformations have been detected by now and there has been no premature onset of puberty. However, from a reproductive and genetic point of view there are some concerns for the future, mainly because of possible fertility problems."
Notes:
The total numbers for the children checked for minor malformations are slightly lower than those checked for major malformations because, after checking for major malformations, five ICSI children and two SC children were given a routine paediatric examination rather than being examined against a checklist for minor malformations.
Abstract no: O-014 Monday 11.15-11.30 hrs CET (Forum Hall, Level 2-4)