Although in vitro fertilisation (IVF) births account for only a small percentage (1.3%) of all births nationally, over 20% of all multiple births are IVF births. This means that IVF births contribute a disproportionately large number of multiple births to the overall rate.
At present, about 1 in 4 IVF pregnancies result in multiples: this is around 20 times higher than the rate after natural conception.
During IVF, eggs are removed from the ovaries and fertilised with sperm in a dish in the laboratory. The developing embryos can be left for either 2 to 3 days, or 5 to 6 days before being transferred to the woman’s womb.
"We can no longer accept that more than 1 in 5 pregnancies resulting from IVF are twins or more, with all the attendant risks to the mother and child that this brings. After all, IVF babies also deserve the best start in life."
Professor Peter Braude, Head of the Department of Women’s Health, King’s College London
Multiple birth is the single biggest risk to the health and welfare of children born after IVF. See Risks to the mother and Risks to the child.
Currently, after IVF and intra-cytoplasmic sperm injection (ICSI) around 24% of pregnancies are multiple, compared with only 1 – 2% after natural conception.
This can be directly related to the fact that IVF normally involves the transferring of 2 or 3 embryos to the womb.
If you or your clinician considers that you are at risk of multiple pregnancy, you should discuss transferring only 1 embryo (single embryo transfer, known as SET).
For further information see
Are you going through fertility treatment and want to know more about the risks of multiple births? The Infertility Newtork UK (INUK) have published a factsheet that addresses a number of common concerns and questions that fertility treatment patients have.
Download the factsheet (pdf 116Kb)
The HFEA want to hear your views on single embryo transfer.
Your feedback will help them develop their approach to the risk of multiple births from fertility treatment.