How many embryos should be transferred?

Posted on 3 September 2019

IVF technology today allows us to safely vitrify (freeze) embryos. That is why the aim of an IVF cycle should be to create one baby at a time.

There are some cases where Embryo Transfer (ET) x 2 can be considered. I use this tactic (with my patients’ consent and agreement) in cases where IVF success has been tough to achieve and also where there are no absolute contradictions to twin pregnancy. By that I mean, the general health of a mother (and her uterus) is good.

ET x 2 does boost a woman’s chance of conception, so why is it not routinely practiced?

The Pregnancy:

ET x 2 doubles a woman’s risk of twin pregnancy and increases her risk of higher order multiple pregnancies (identical twins happen inevitably – we can’t stop an embryo from splitting and that’s more common in IVF)

Twin pregnancies are considered high risk. A mother of twins is more likely to suffer blood pressure problems, pre-eclampsia, gestational diabetes and preterm labour. She is much more likely to require a caesarean delivery. She is also more likely to suffer uterine and vaginal prolapse, varicose veins, pelvic instability and pain, stretch marks (the list goes on).

The baby

We say a baby has reached the “full term zone” after 37 weeks gestation. Most twins are delivered before 36 weeks and some much earlier.

Being born significantly prematurely puts babies at high risk of many disabilities like cerebral palsy, vision impairment, respiratory problems, learning difficulties. Some babies who are born prematurely unfortunately don’t make it – a tragedy for their parents. Others may eventually be ok but still need to spend months in neonatal intensive care, separated from their parents.

Take home message: think carefully before asking your fertility specialist to perform ET x 2. Having twins is not an easy option.


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