What Are the Risk of Twin Pregnancy in Surrogacy Process?

By (embryologist).
Last Update: 09/18/2015

In order to increase the chances of success of IVF treatment, many assisted reproduction professionals tend to transfer more than one embryo. That way, if one do not implant, another may do it. But what if both embryos implant, i.e. a twin pregnancy?

In the face of this attitude,it is important to keep in mind that a twin pregnancy poses a greater risk.

The different sections of this article have been assembled into the following table of contents.

Complications of Multiple Pregnancy

The surrogacy process is something so complex and so emotionally and economically demanding that many couples prefer to transfer two embryos to ensure success without worrying about the option of having twins, and even some prefer it, so as not to have to go through the process again if they want another child. However, they are not aware of the risks of multiple pregnancy.

Multiple pregnancy, i.e. two, three or more fetuses, poses a greater risk to both the mother and future babies throughout the pregnancy and also at the time of delivery.

For this reason, there are legislations that limit the number of embryos to be transferred. Many studies are currently dedicated to increasing the success of implantation with the ultimate goal of reducing double transfers and following the trend of single embryo transfers.

Among the most common complications of twin pregnancies are the following:

  • Strain of the uterus: The uterus tends to distend and puts more pressure on other organs.
  • Major placenta and more hormonal release.
  • Increased weight gain.
  • Placenta previa: When there is more than one placenta or a larger placenta, the cervix may become obstructed and lead to vaginal bleeding and increased risk of preterm birth.
  • High blood pressure
  • Increased likelihood of miscarriage
  • Preeclampsia.
  • Excessive vomiting (Hyperemesis gravidarum) and other digestive disorders.
  • Postpartum hemorrhage.

Risks for the newborn

In a twin pregnancy, the likelihood of genetic alterations in the fetuses is increased. In addition, twin to twin transfusion syndrome can occur in which one fetus receives excess blood and the other receives a deficiency due to the communication of its blood vessels.

It is very common for twin babies to be born with a lower weight than usual. Low birth weight may be seen in only one twin due to discordant growth or both. The so-called “evanescent twin” may also occur, whereby one of the two twins is reabsorbed without affecting the development of the surviving fetus.

Finally, there is a high risk of premature birth (between 25 and 45%). In fact, a large number of twin pregnancies do not reach 37 weeks of gestation, with the complications that this implies.

Premature birth is associated with an increased risk of infant morbidity and mortality. In addition, long-term consequences such as neurological disability or respiratory distress syndrome, intracranial haemorrhage or blindness are more common.

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Authors and contributors

 Andrea Rodrigo
Andrea Rodrigo
Embryologist
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics. More information about Andrea Rodrigo

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