Dr. Mary Wingfield:

It depends very much on the couple. If it is a young couple and there is nothing obvious presenting and they are fit and healthy, we would usually say they need to be trying to get pregnant for a year, but if it is an older couple, most people would now say if they have been trying to get pregnant and have been unsuccessful that after six months they would need to be investigated and would possibly need treatment.

We collect the eggs and then we form embryos. The vast majority of eggs do not lead to embryos. We wait for three to five days for embryos to develop and then choose one or two, or occasionally three, embryos to put back in a woman's uterus. That would be the standard in Ireland. Very few people would put back in more than three. If the person has good embryos, there is a big trend towards ideally putting back in one embryo to reduce the chance of multiple pregnancy. However, some people do not get good quality embryos or they may have had two or three failed IVF cycles previously, or if the woman is older, she may need two and occasionally three embryos put back in.

In terms of embryos used for training and research purposes, most people going through the process will need and use all their embryos but some couples will end up with extra embryos they do not need. At present, they can donate them to another couple but that is very difficult, and very few people opt for that.

We can dispose of, or donate, embryos. Currently, there is nothing to stop us donating them for research, but no one in Ireland is conducting research on embryos.