Twins may seem like a good option when you have tried for so long to have your family. However multiple pregnancy and birth is the most serious risk of any assisted conception treatment.

There are risks to the mother as well as to the babies. These risks include high blood pressure, gestational diabetes and anaemia.

At least half of twins are born prematurely and underweight, which can lead to serious health problems and even death. There is also a much higher risk of early or late miscarriage if you’re carrying multiple babies. Longer term, there are also emotional, practical and financial repercussions to a multiple birth.

Experts agree that the aim of all fertility treatment should be the birth of a healthy baby with minimum risks for the mother. For many women, this can be achieved by transferring one embryo and for this reason you may be advised to have a single embryo replaced (single embryo transfer or SET). The clinic staff will assess your suitability for this based on your age, whether you have had any previous IVF cycles and on the quality of your embryos. To ensure you have the best possible outcome, staff at your clinic will assess your case individually.

One in every twelve twin pregnancies results in at least one baby dying or having a significant disability. This is a daunting statistic, but single embryo transfer will dramatically reduce the risk of this happening to you. Some people think that single embryo transfer might reduce the chances of success; in reality, replacing two embryos does not double your chances of success, but it does increase your chances of a multiple pregnancy. To ensure you are given the best advice, the embryologist at your clinic will assess the quality of your embryos prior to the transfer. The best quality embryo will be replaced and any further good quality embryos may be frozen and stored for you for future use.

Working closely with the Human Fertilisation and Embryology Authority, and the One at a Time Organisation, we have produced information on single embryo transfer (SET) to help you understand the issues.

Download our factsheet on SET for patients, or our factsheet specifically for health professionals below.

FACTSHEET: Single Embryo Transfer for Patients

FACTSHEET: Single Embryo Transfer for Health Professionals

FACTSHEET: Single Embryo Transfer for Patients (Welsh Version)

FACTSHEET: Single Embryo Transfer for Patients (Scotland)

FACTSHEET: Single Embryo Transfer for Health Professionals (Scotland)