CHILDREN BORN using in vitro fertilisation and other assisted reproductive technologies (Art)generally do well, but researchers are now studying the reasons why a small fraction are more likely to have health problems in later life.
Some are more prone to high blood pressure, type II diabetes and obesity, a scientific meeting has heard.
Reliance on these technologies has also allowed otherwise infertile couples to have children that would have been impossible in the past. This in turn may produce offspring who are themselves infertile, a session of the American Association for the Advancement of Science’s annual meeting in San Diego heard. The conference drew to a close yesterday.
Louise Brown, the world’s first baby conceived using assisted reproductive technologies was born on July 25th, 1978.
Researchers have wondered since then whether unforeseen long term health issues might arise. “We are doing a big experiment here,” stated Prof Carmen Sapienza of the Fels Institute for Cancer Research at Temple University in Philadelphia.
While the great majority of those born using Art are healthy and well, these individuals do have a slightly higher risk of diseases related to how they burn sugars and fats, Prof Sapienza said.
It was essential that long term follow up studies were done in order to spot any differences between children conceived naturally and those conceived using Art, stated Prof Andre Van Steirteghem of the Brussels Free University Centre for Reproductive Medicine.
“Several millions of children have been born around the world after reproductive technology. In some countries they represent 3 to 5 per cent of all births. Overall the children do well so this is a positive,” he said.
“Yet there are a few problems for these children.” Researchers are trying to separate out the causes for this slightly increased risk of metabolic disorders. Prof Sapienza is doing genetic analysis looking for differences between those conceived by conventional versus Art means.
He has found several changes in genes in some individuals associated with metabolic conditions such as diabetes.
One thing that might reduce the likelihood of metabolic disorders was to reduce the number of births per pregnancy, given multiple births are commonplace when using Art, Prof Steirteghem said. Multiple births also tended to result in premature babies that have a resultant low birth weight.
This in itself is a risk factor for obesity and blood pressure in later life, Prof Steirteghem said. Yet Art babies are still more likely to have a low birth weight than babies conceived naturally, he added.
Questions also remain over whether the infertility in parents who rely on Art will in turn perpetuate this infertility, stated Prof Dolores Lamb of Baylor College of Medicine in Houston, Texas. She is an expert in male infertility and described how “extreme measures” can be used to locate just a few viable sperms in an otherwise sterile man in order to help him have children. “What we don’t know is whether these children will be infertile like their parents,” she said.
Asked whether this might lead to increased incidence of male infertility, Prof Steirteghem said: “The answer to that is maybe yes. That may mean the next generation will be infertile as well. If there is a genetic origin then this may be transmitted to the next generation.”