By Laura Garrido BSc, MSc (embryologist) and Manuel Fernández MD, PhD (gynecologist).
Last Update: 05/12/2014

Dr Manuel Fernández, director of Seville’s IVI Clinic, answers some questions related to multiple births. He bets on a single embryo transfer.

Question: A large number of multiple births have occurred throughout the history of reproductive medicine. How can multiple gestations be prevented?

Answer: There are lots of actions to be taken, most of them being implemented with increasing success. As for in vitro fertilisation, a three-embryo transfer should be avoided: cases with a good prognosis should bet on a single embryo transfer instead. This requires a process of raising awareness not only by the couple undergoing the treatment but also by the professional team. The “success” of an assisted reproductive treatment does not consist only on achieving pregnancy. More and more, we need to be aware that the ultimate aim should be having a healthy baby, that is to say, that the child is not born too early. Despite changing this mindset may be difficult, we insist on the need to prevent multiple births.

Q: Spanish law on this matter allows a two- or three-embryo transfer. Do you think it would be beneficial to amend it?

A: In my opinion, amending it so that a three-embryo transfer was not allowed in any case would be advisable. However, a two-embryo transfer appears to be beneficial for the moment. The problem is that not every clinic has a proposed embryo freezing programme which allows pursuing the same chances for success in a two-embryo transfer than in a single embryo one and postponing the remaining embryo for the following cycle by keeping it frozen. New vitrification techniques are greatly helping these single embryo transfer policies; therefore, as soon as these policies become standardized in those clinics which still do not get good results, it would be appropriate to raise the issue at this point in order to ban or, at least, to encourage a single embryo transfer as other countries of northern Europe have already done.

Q: Which specific risks or dangers are involved in this type of pregnancy?

A: Although the potential risks for the foetuses and the mother are becoming increasingly controlled and less frequent, it is precisely in cases of multiple births where problems for the mother may raise, such as high blood pressure, diabetes, prematurity, problems at the time of delivery, etc. As for the baby, the potential dangers are those related to prematurity, most of them considered as mild and transitional, although some may become a serious health issue.

Q: Sometimes, the patients themselves are the ones who think that transferring more than a single embryo increases the chances for success. Is this indeed so?

A: Yes, it is. By transferring two embryos instead of a single embryo, the chances for pregnancy are greater. The importance of a good embryo freezing programme is that it allows the chances to be the same if we compare performing a two-embryo transfer at the same time with performing a two-embryo transfer in two different cycles, one of them after being frozen. The concept is “1 + 1 = 2″.

Q: In the United States, for instance, there is no limit regarding the number of embryos that should be transferred. Where do you stand on this?

A: I think that the European policy is much healthier at aiming to encourage a single embryo transfer in order to avoid multiple births.

Authors and contributors

 Laura Garrido
BSc, MSc
Bachelor's Degree in Biotechnology from the Pablo de Olavide University (UPO) of Seville, Spain. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). Experience at IVF, andrology, and general analysis laboratories. Embryologist specialized in Assisted Reproduction. More information
 Manuel Fernández
Graduate in Medicine and Surgery from the University of Seville. Specialist in Obstetrics and Gynecology from the University Hospital Virgen Macarena de Seville. Master's Degree in Assisted Reproduction from the Rey Juan Carlos University of Madrid. Gynecologist at IVI Seville since 2003 and Director since 2005. More information
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