Fewer Embryos for Transfer

The miracle of conception is one of life’s greatest mysteries. That is why it is so devastating to find out you and your partner cannot conceive. After numerous attempts to get pregnant, you feel frustrated and confused.

You should know you are not alone. Up to 5,000,000 American couples suffer from infertility every year and 20% of those decide to undergo in vitro fertilization.

Since 1981, when it was first introduced in the United States, more than 139,000 babies have been born through embryo transfer. However, IVF treatment has long been considered a controversial topic. In particular, the debate about in vitro fertilization has centered around the number of embryos transferred into a woman’s uterus.

Guidelines and Regulations

If you and your partner were to go see an infertility specialist, they would advise you that the number of embryos transferred during the IVF treatment depends on three factors: the cause of infertility, a woman’s age and her reserve of ovaries.

According to practice guidelines published in the medical journal Fertility and Sterility in 2004, though, female patients:

  • under the age of 35 may have up to two embryos transferred
  • between ages 35 and 37 may have up to two to three embryos transferred
  • between ages 38 to 40 may have up to four embryos transferred
  • over the age of 40 may have up to five embryos transferred
  • For those who have had repeated failed IVF treatments, more embryos may be transferred

Of course, one of the biggest problems with transferring multiple embryos is the risk of having a multiple birth, which can lead to a high-risk pregnancy, potentially putting the life of both mother and children in danger.

For this reason, doctors and patients have long struggled with the dilemma of just how many embryos should be transferred. Traditional theories held that the more embryos your transferred, the great the likelihood of a pregnancy occurring.

Yet, by transferring more embryos, there was a greater risk for an unhealthy pregnancy and potentially miscarriage of one or more of the embryos.

Recently, though, Finnish researchers have found that perhaps it is not the quantity of embryos transferred that matter.


New studies conducted in Finland have shown that the quality of the embryo being transferred is more important than a woman’s age as well as the number of embryos being transferred.

Initial studies done on the success rates of IVF treatment revealed that younger women under the age of 35 had a pregnancy success rate of 31% to 35% with a single healthy embryo, while their live birth rate was 27% to 30%. However, these results were not limited to just those women under the age of 35.

The second set of studies conducted in Finland showed that women over the age of 35 could become pregnant with the transfer of a single healthy embryo. Scientists conducted 1,224 IVF cycles and 828 frozen embryo transfers.

About 33% of the women became pregnant after one cycle and had a live birth rate of 26%. It is important to note, though, that the women in these studies were exclusively chosen out of a pool of eligible women for single embryo transfer. Only those with good quality embryos were selected.

Of course, the idea of transferring just one embryo is not typical practice; until recently, in the United States, three or more embryos were normally transplanted into a woman’s uterus to ensure pregnancy, commonly resulting in multiple births. But are these findings likely to change the way Americans think about embryo transfer?

More or Less?

According to experts, there are major differences between the Finnish and American health care systems that influence the outcome of IVF treatments. For example, IVF treatments can cost from $10,000 to $15,000 in the United States while in Finland they are free to infertile couples.

Due to the high cost of IVF treatments, American women are more likely to try alternative infertility treatments until they can afford to use IVF.

That being said, it is becoming more common in the United States to keep the number of embryos transferred to a minimum in order to avoid the risk of a multiple pregnancy. Many other countries have also begun to employ this practice for in vitro fertilization.

Even so, the results of the Finnish studies are promising. While some women may need to have more embryos transferred, the study shows that those women that are ideal candidates for IVF can still successfully become pregnant even if just one embryo is transferred. Not only will this improve her pregnancy outcome, it will also contribute her having a healthier child.


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