New Method to Reduces the Risk of Twin Births in IVF Pregnancies

Doctors in Sweden on Monday showed a new method that says they dramatically reduce the risk of multiple births through in-vitro fertilitation (IVF) without affecting the chance of having a baby.

This technique helps doctors determine the possibility of delivering healthy babies through IVF, they say.

At present, fertility clinics tend to move some embryos into the uterus to increase the chances of giving birth, but this often becomes

twin pregnancy carries a high risk of complications for the mother as well as the baby's underweight so that it has difficulties in its development.

"There are several other predictive models, but this is the first time that the difference between the possibility of (getting pregnant) if you move one or two embryos, means also taking into account the risk of twins," Jan Holte from the Carl von Linne clinic told AFP.

With this model, "When moving an embryo, if we see that the risk of twins is too high, then we will only move one embryo and freeze the other," Holte explained.

Over four years (2004-2007), his clinic had moved 3,410 embryos. The model helped reduce the rate of multiple pregnancies through IVF from about 26 percent in the previous four-year period to 1.9 percent.

At the same time, the birth rate with embryo transfer via IVF fell slightly from 29.1 percent to 24.6 percent, while frozen embryos were stored and thawed, remaining almost the same at around 31.1 percent.

Effects on this model are a woman's age, egg count and ovarian response, information about whether the woman has had an effort through an IVF pregnancy and the quality of her embryos.

In some cases, "excess embryos, which are usually transferred to many clinics around the world, greatly increase the risk of twins but give little chance for pregnancy," Holte explained again.

For example, in a case where a young woman who responded well to fertility treatments, then removed two of the best-quality embryos, had a 65 percent chance of becoming pregnant. But there will be one or two possibilities to become twins.

"If we don't move just one (the best embryo), the chances of getting pregnant will still be more than 50 percent," Holte said. "We reduced overall pregnancy to very little, but we reduced the risk of twin pregnancy to zero.

In some cases, the doctor will only remove one embryo and freeze the other.

"When the first embryo transfer did not produce results, then we moved the other embryos," Holte said again. "In patients, this will give about 40 percent chance of getting pregnant so we don't waste this opportunity.

To develop this model, Holte and his team analyzed data from 3,223 embryos that were transferred between 1999 and 2002 and initially looked at 80 factors before approaching to four.

It can now be used in four other clinics besides Holte's own, three in Sweden and one in Italy.

"I think it might be a good choice for other clinics to try it, because in the long run, you can solve the real problem of having multiple pregnancy possibilities and ending up with the same total number of births," Holte said.

This model is easy to use in all clinics because it has basic data and can calculate embryos using the same method quite easily, Holte added. It is possible to test the model with the help of web-based software.

This performance was presented on Monday at the annual conference held by the European Society of Human Reproduction and Embryology (ESHRE) in Stockholm.