SEEING double has become an increasingly common experience, thanks to the rise in the number of multiple births.

Over the past 30 years, the number of twin births has risen from 6,000 a year to 10,000. This increase has been put down to the use of IVF to assist conception.

When a couple receive fertility treatment of this kind, they are given the choice of having one or two, and in the case of women over 40, three, fertilized embryos, implanted back in their womb. When two or three are implanted, it means there is the chance that all of the embryos could take and result in a multiple pregnancy.

It is calculated that around 90 per cent of IVF cycles in Britain currently use two embryos because clinics and couples fear that using only one will reduce the pregnancy rates.

However, the Human Fertilisation and Embryology Authority (HFEA) are calling on clinics to try and reduce the number of multiple births, because of the associated health risks.

These include an increased risk of premature birth, problems where one baby will grow at the cost of the other, and a higher chance of the mother developing pre-eclampsia.

It is said that the chances of complications in the mother increase sixfold and the risk of death of the babies in the first month sevenfold.

As a result, the HFEA has told clinics to cut IVF twin and triplet births from one in four to one in 10. To do this, they want clinics to choose couples with the best chance of pregnancy, usually the youngest, to have just one embryo transferred.

A new technique, which involves growing the fertilised embryos for a couple of extra days in the laboratory and identifying the best single embryo (or blastocyst as they are known at this stage) for implantation, was tested by specialists at Guy's and St Thomas' Hospital, London.

They found that despite only transferring one blastocyst to the womb, rather than two, they increased the pregnancy rate from 27 per cent to 32 per cent.

The problem for couples however, is that the NHS only offers one free round of IVF treatment and private clinics can prove costly, making them We speak to two women who know first hand about the issues surrounding multiple births, a mum who has had twins via IVF and the head of midwifery at Southend Hospital Tamsin Bowers, of Rectory Road, Hadleigh, mum to twins Isabella and Francesca, four, and Azaria, 18 months.

"As a mother of twins, which were as a result of IVF, I know only too well the desire to have a family coupled with the complication surrounding multiple births.

When you first discover that your pregnancy will not be a result of a normal conception, but will need the expertise of somebody in the field of fertility to make it happen, your first worry is not that of having a multiple birth but just getting to the birth in the first place.

I, like, I am sure, 90 per cent of couples will tell you, opted to have two embryos implanted to raise my chances and as I only had two surviving embryos did not want to destroy a life that I had fought so hard to create.

I now have three beautiful daughters thanks to the miracle of IVF, the third being born in 2006, and a fantastic clinic in Sweden and would not change anything for the world.

I feel that more than two embryos implanted is too big a risk to take, but that given the option again I would still have two implanted now. I also feel that this should be the right of other couples that find themselves in this unimaginable situation.

As the costs of IVF are so high and the chances of NHS funding so low, couples should be given the right to make the decision of how many embryos to implant. Cost being a large factor it also plays a role in whether or not couples would be able to fund another course of treatment in the future for a sibling and this again will play a crucial part in their choices. Having two embryos implanted may only increase your chances slightly but when faced with the statistics should we not be given the right to choose the higher option?

In addition, Blastocyst culture is not suitable for all those embarking upon IVF as the requirements for this type of fertilisation are complex with many requisites. Age, egg production and quality play a key role in those chosen for Blastocyst and this should not be forgotten when choosing the future of IVF and its impact on all variations of its users."

Liz Glenister, head of midwifery and gynaecology at Southend Hospital "Twins seem to be much more common now than they've ever been. But the health issues associated with them differ, whether they are identical or non-identical.

Non-identical twins, which are the types formed by IVF, just carry a slightly greater risk. Because the mum gets much bigger carrying two babies rather than one, the chances of her carrying them to full term are slightly reduced.

Identical twins carry additional problems. Identical twins are formed when one fertilised egg splits into two. This doesn't happen with IVF. If twins are formed during IVF it is because two implanted eggs have taken rather than one.

Because identical twins share the same placenta and blood supply, you can get the situation where one baby feeds off the other, and as one gets bigger the other gets smaller. Also if one twin dies, it is less likely that the other one will survive unless quick action is taken to deliver it.

From a mother's point of view, being pregnant anyway takes its toll. With two it takes its toll and then some. The issue is the ability to cope afterwards with two babies of the same age. But I imagine when women are so desperate to have a baby then they're happy to have two.

Things have changed a lot with IVF over the years. I remember years ago women being implanted with six or seven eggs in the hope one would take. From that point of view, things are a lot more sensible now. I know that most NHS funded hospitals will only put back one or two, meaning that you will only ever get a maximum of two babies.

This is not un-manageable from a midwifery point of view.

The NHS only fund one cycle of IVF so it makes sense to give women going through the process as much help as possible. If you put two eggs back in, that increases the odds of becoming pregnant.

I can only imagine how awful it must be trying for years and years, being only given one shot at being a parent then I don't see the logic in restricting it to only one.

I just think it's a bit short sighted, unless the government funds a second cycle of IVF."