IVF increases women's risk of having a baby with Down's syndrome

The study suggests that women, who are over 35, and are using powerful drugs to boost large numbers of eggs to harvest for in-vitro fertilisation (IVF) may might face extra risks of pregnancy loss and the development of genetic defects in the embryo.

IVF or in-vitro fertilization is a fertility treatment in which eggs are fertilized in a laboratory by donor sperm and implanted in the womb. It is believed that the more eggs available, the higher the chances of getting a possible pregnancy.

The practice has long been opposed by the Catholic Church and has been deemed as morally unacceptable.

IVF drugs may cause harm to eggs
Now a new study has found fresh evidence that using powerful drugs to boost the number of eggs might damage the eggs themselves, thus reducing the likelihood of having a healthy baby.

The worrying evidence showed that IVF treatment may result in failure to get pregnant, or losing the baby, and more rarely the birth of children with conditions such as Down’s syndrome, a chromosomal disorder in which extra genetic material causes delays in the way a child develops, both physically and mentally.

According to study lead author Professor Alan Handyside, director of The London Bridge Fertility, Gynaecology and Genetics Centre, the findings showed that drug stimulation of the ovaries may trigger more chromosomal abnormalities in the eggs produced, and any embryos created.

These chromosomal abnormalities might result in IVF failure, miscarriage, and sometimes Down's syndrome like abnormalities, suggest Handyside and colleagues from eight countries.

Study details
The team based their findings on tests involving 34 women, with an average age of 40 years, who were undergoing IVF treatment.

For the study, the scientists studied polar bodies, small cells that are the by-product of egg development and can be safely removed for analysis.

They found 55 percent of errors occurred at the first stage i.e. at ovulation stage and 45 percent at the second stage, which is fertilization.

"This suggests that the stimulation process to maximise the number of eggs you get, may be causing some of these abnormalities, because this pattern is different from normal pregnancy. The stimulation process may be triggering more errors," said Handyside.

More research needed
Under the age of 35, mild stimulation is used to produce extra eggs. But over 35, when the ovaries are naturally producing fewer eggs, over-stimulation – which occasionally can be fatal, has conventionally been used.

"The results of such research should enable us to identify better clinical strategies to reduce the incidence of chromosome errors in older women undergoing IVF," Handyside said in a statement.

Co-author Professor Joep Geraedts from the Department of Genetics and Cell Biology, Maastricht University, says in a statement: "We also believe that our research will help identify women who want to have their own offspring but have practically no chance of doing so that we can advise them to use donor oocytes [cells from which eggs develop]."

Geraedts continues, "This in itself is already a big step forward that will aid couples hoping for a healthy pregnancy and birth to be able to achieve one."

The findings were presented today to the European Society of Human Reproduction and Embryology (ESHRE) conference in Stockholm, Sweden.

About Down’s syndrome
Down’s syndrome, also known as Trisomy 21, is a chromosomal disorder caused by the presence of an extra 21st chromosome commonly picked-up with amniocentesis during pregnancy or at time of birth.

Down’s syndrome is typically associated with impaired cognitive ability and physical growth. It is the most common genetic cause of mental retardation, heart defects, dementia, and leukemia in later life.

However, other health concerns include a pronounced risk for congenital heart defects, gastroesophageal reflux disease, frequent ear infections, obstructive sleep apnea, and thyroid dysfunction.

Infants with Down's syndrome have three copies of the Chromosome 21 instead of the normal two. The genetic condition affects about one in every 700 live births.

The risk of giving birth to a baby with Down's syndrome rises as women get older, with the danger for a 40-year-old mother nearly 16 times than that for one who is 25.