The risks of twin pregnancies in surrogacy : Why is it recommended to transfer a single embryo?

In surrogacy, every medical and ethical decision has a major impact. One of the most important decisions in the in vitro fertilization (IVF) process is determining how many embryos to transfer to the surrogate’s uterus. In the past, it was common to transfer two or more embryos to increase the chances of pregnancy, but today reproductive medicine has advanced and the international recommendation is clear: opt for single embryo transfer (SET).

The main reason is to protect the health of the surrogate mother and the future baby, reducing the risks involved in multiple pregnancies, especially twins. Although for many families the idea of having twins may be exciting, in the context of surrogacy it is a scenario with greater medical complications and, therefore, not recommended.

Medical risks for the surrogate mother

A twin pregnancy places a much greater strain on the surrogate mother’s body and carries risks that should not be overlooked. Among the most common complications are:

• Premature birth: more than 60% of twin pregnancies end before week 37, which significantly increases the need for neonatal intensive care.
• Preeclampsia and eclampsia: Hypertensive disorders are more common in multiple pregnancies, putting the health and safety of the pregnant woman at risk.
• Gestational diabetes: increased metabolic demands increase the likelihood of complications that can affect both fetal development and delivery.
• Caesarean section almost inevitable: in most cases, the birth of twins requires surgical intervention, with a longer recovery and greater postoperative risks.

In the context of surrogacy, where a woman carries a child for another family, protecting her well-being is an absolute priority. Protecting the pregnant woman from a high-risk pregnancy is a decision that responds both to best medical practice and to the ethical commitment of the process.

Risks for babies

Babies born from twin pregnancies often face greater vulnerabilities from the outset. Among the most common are:

• Prematurity and low birth weight: twins are born, on average, weighing one kilogram less than babies from single pregnancies, which increases the need for special care.
• Respiratory problems: because they are born prematurely, many require respiratory assistance and prolonged stays in neonatal units.
• Neurological complications: The risk of intracranial hemorrhage or cerebral palsy is higher in premature twin newborns.
• Higher neonatal mortality: Statistics confirm that the probability of loss is higher than in single pregnancies.

In the context of surrogacy, where the intended parents have placed so much hope and trust, these complications represent not only a medical challenge, but also a considerable emotional and financial burden.

Elective single embryo transfer (SET)

Elective single embryo transfer (SET) is now a medical practice supported by scientific evidence and endorsed by organizations such as ESHRE and ASRM. Advances in embryo culture to the blastocyst stage and in vitrification allow a single selected embryo to offer implantation rates comparable to those of multiple transfers, but without increasing risks to the pregnant woman or the newborn.

If the first transfer is unsuccessful, the vitrified embryos can be used in subsequent cycles, ensuring high cumulative success rates. This reduces obstetric and neonatal complications, prioritizing both the safety of the pregnant woman and the health of the baby. In surrogacy, SET is confirmed as the most effective, ethical, and responsible option.

Conclusion

In surrogacy, safety is the priority. Although the idea of a twin pregnancy may seem attractive, the medical, ethical, and legal risks are too high. For this reason, assisted reproduction specialists and leading clinics consistently recommend the transfer of a single embryo.

This strategy offers a responsible balance: it maximizes the chances of success, minimizes risks, and ensures respect for all those involved in the complex and delicate process of surrogacy.