For most people, news of a pregnancy brings feelings of joy and excitement and maybe some nerves and trepidation too. But what if you knew there was a chance your child could be born with a life-limiting condition? Those nerves and trepidation could reach a frightening new level.

However, a new fertility technique, recently introduced in Ireland, is offering some people the opportunity to reduce their unborn child's risk of developing certain conditions.

Pre-implantation genetic diagnosis (PGD) is a specialised fertility technique which allows people with a specific inherited condition the option of trying to avoid passing it on to their own children.

People who are candidates for PGD include carriers of single gene defects, such as cystic fibrosis (CF). This is the most commonly inherited genetic disease in Ireland. One in 19 Irish adults is a carrier of the altered gene that causes it and if both partners carry the CF gene, there is a one in four chance that their baby will have the condition which, without a heart/lung transplant, is a life-limiting condition.

Other candidates for PGD include people who themselves are affected by chromosomal disorders such as Duchenne muscular dystrophy, myotonic dystrophy, haemophilia A and fragile X syndrome.

Just two fertility centres in the country are licensed to provide PGD - Cork Fertility Centre and Beacon CARE Fertility in Dublin - and the Cork centre recently announced the first confirmed pregnancy in Ireland using this technique.

"Prior to this, Irish couples had to travel abroad, usually to the Guy's and St Thomas' Hospital in London. This involved a lot of stress for those involved and extra costs," explained Dr John Waterstone, medical director of Cork Fertility Centre.

He said that for those who did not want to travel, there were other options, but these were not always a couple's first choice either.

Options

"We have had couples coming in looking for information on donor sperm treatment because they were so paranoid that they would pass on a particular condition to their child. But this is not what the couples really wanted," he explained.

He said others were willing to ‘play roulette' and ‘take a chance' on a pregnancy, but again, they ‘tended to be nervous about that'.

Some couples also opted to get pregnant and then have the baby screened during pregnancy for various conditions. If there is a condition there, they have the option of travelling for an abortion, however ‘a lot of couples are not comfortable with this', according to Dr Waterstone.

The PGD technique involves generating a number of embryos via IVF (in vitro fertilisation). With IVF, a woman's eggs are fertilised with sperm outside the body in a test tube and the resulting embryo is placed back inside her womb.

In the case of PGD, before the embryos are put into the womb, they are biopsied, which means one cell is carefully removed from each cell. These biopsied cells are then sent to the Genetic Centre in the UK to be analysed.

Only those embryos that are diagnosed as being unaffected by the particular condition are selected for transfer into the womb of the woman.

"While IVF is used, these women (or their partners) do not necessarily have fertility problems," Dr Waterstone noted.

However, this does not necessarily mean that the chances of getting pregnant are any higher when compared to women undergoing IVF for fertility problems.

Dr Waterstone explained that this is still a ‘very complicated' procedure and one of the keys to it is obtaining a high number of eggs.

"We want to see at least 10-20 mature eggs. A small number of eggs is no good, which is why PGD is aimed at youngish women - those under the age of 35. The older a woman gets, the fewer eggs she produces," he said.

He emphasised that each case is different and the technique may work for women in their late 30s as well. A thorough assessment can estimate how many eggs will be produced during IVF. However, if too few eggs will be produced, PGD will not be recommended.

"For example, in the case of the confirmed pregnancy, 30 eggs were produced but following screening, just five were deemed potential candidates," he explained.

In the case of that woman, PGD was carried out to try to avoid CF. The first embryo implanted in the woman worked and she is now in the early stages of pregnancy.

Dr Waterstone pointed out that for some people, the first time they realise they are a carrier of the CF gene is when they have a baby born with the condition. As a result, they may choose PGD if they opt to have more children.

In the future however, people will be aware if they are carriers of the CF gene because since July 1, 2011, all newborn children in Ireland are routinely tested for CF as part of the existing newborn bloodspot programme, known as the 'heel prick test'. As a result of this test, parents will learn if their children have CF or are carriers of the CF gene. If CF or the CF gene is confirmed, these infants may opt for PGD when they later decide to start their own families.

Ethics

It is impossible to discuss fertility techniques, particularly newer ones, without the issue of ethics coming up, something that Dr Waterstone acknowledges. He believes many people view techniques like this as a ‘slippery slope', particularly as some eggs are discarded without being used.

However, he insisted that people working in this area in Ireland are ‘not doing crazy things'.

Currently in Ireland, there is no legislation covering this vast area, however there is in the UK and there is even specific legislation there relating to PGD and what conditions can and cannot be considered when opting for it.

"There is a very specific list of conditions in the UK and very sensible rules and we use those UK guidelines. So if someone comes into us regarding a condition that is not on the UK list, we simply will not consider it," he explained.

Dr Waterstone acknowledged that this is a relatively small area in fertility, so he is not expecting ‘huge numbers' to avail of it. However, since the first pregnancy using this technique was announced in early November, the Cork centre has had ‘several enquiries'.

The cost of PGD treatment at Cork Fertility Centre is €9,000-€10,000, although patients can claim some of this back using the Med 1 form.

 


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