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Multiple gestation after IVF – One embryo at a time…?

Multiple gestation? Better one embryo at a time...
Start new life…one at a time….

One of the principal problems with in vitro fertilisation is the fact that it is still difficult to predict whether an embryo is capable of implantation. We now know that growth rate, lack of ‘fragmentation’ and the presence of a single nucleus in each blastomere are indicative of a good quality embryo. Why is it then that top quality embryos sometimes do not lead to pregnancy, whereas sometimes the transfer of low quality embryos can still cause a viable pregnancy?


For these reasons, practitioners of in vitro fertilisation, as well as the patients themselves, prefer the transfer of more than a single embryo per transfer.


This unfortunately leads to a second aspect of in vitro fertilisation – the occurrence of multiple gestation.


How much of a problem is multiple gestation

Multiple gestation occurs when more than 1 embryo implants into the uterus. In nature, 1 in 80 (1.3%) of pregnancies are twins. In assisted reproduction, the figure is as high as 20%.


Incidence of multiple gestation after IVF
Country 2010 2009
Switzerland 18.4% 17.8%
UK 23.6% 22%
USA 32% 33%


Occasionally, even a single embryo can give rise to a multiple gestation: this is the case for identical twins but is an uncontrollable circumstance and so cannot be avoided. Therefore, usually, multiple gestation occurs after assisted reproduction and is ‘induced’ through the transfer of more than 1 embryo.


Many patients relish having twins at a single blow. They feel it is ‘value for money’ or creating a family all in one blow. Gynecologists and obsteticians are a little more cautious for the following reasons:


Common risks of multiple gestation after IVF
Risks to the mother Risks for the unborn
Singleton 5% risk of preterm birth6% risk of preeclampsia2% risk gestational diabetes 0.3% risk of death within 1 month0.17% risk cerebal palsy
Twin 60% risk of preterm birth10-15% risk of pre-eclampsiaGestational diabetes Growth restriction after 30 weeksLow birth weight1% risk death within 1 month

0.62% risk cerebral palsy


Triplet 90% risk of preterm birthTriple risk of pre-eclampsiaGestational diabetes Growth restriction after 27 weeksLow birth weight2% risk of death within 1 month
American Pregnancy Association


In essence, a multiple birth is risky to the mother and unborn child, and could affect the formation of a healthy family.


This is why governments have felt the need to limit the number of embryos that can be legally replaced into the uterus during IVF, and organisations such as the HFEA are carrying out a policy to limit the number of multiple births (such as the One at a time program).


This author agrees with the policy of limiting multiple births. However, there are two other factors to consider. Firstly, in private IVF treatment, money IS a factor. It’s all very well limiting an embryo transfer to a single embryo. But who’s going to pay for the extra cycles needed? Not everybody has sufficient economic means o be able to permit multiple cycles of IVF, whereas they could have had a single cycle. Secondly, and more importantly perhaps, is the psychological effect of muliple failure. Lowering the number of embryos replaced also lowers the pregnancy rate, which means more cycles. Can patients psychologically accept the increased failure rate that comes with single embryo transfer?



One Response to Multiple gestation after IVF – One embryo at a time…?

  1. Alex says:

    Hello, This is my 2nd embryo transfer, I have had 1 embryo replaced at a time. I am waiting for the 2nd outcome, however I would love to hear from couples with whom it worked, how many times did you try with a single embryo?. I am thinking that when this time round this doesn’t work, then possibly 2 at a time?

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