IVF: Are 3 Embryos Too Many to Transfer?
No Justification for More Than 2, Study Finds
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Lower Birth Rates Seen With 3 Embryos continued...
The live birth rate was greater with the transfer of two embryos, compared to one, in women under the age of 40 and in women who were older. Transferring three embryos resulted in a lower birth rate than transferring two in the younger women and made no difference in outcomes in older women.
Compared to single-embryo transfer, transferring two or three embryos was associated with a higher risk for all adverse birth outcomes, including low birth weight and preterm delivery.
Not surprisingly, the overall live birth rate was lower in older women compared to younger ones, no matter how many embryos were transferred.
“A clear implication of our study is that [the] transfer of three embryos should no longer be supported in women of any age,” Nelson and Lawlor write.
60% of IVF Twin Deliveries Preterm
Infertility specialist Liv Bente Romundstad, MD, PhD, of Norway’s St. Olavs University Hospital and the Norwegian University of Science and Technology, says the large number of multiple births in the U.S. resulting from IVF procedures illustrates the problem with multiple embryo transfers.
According to a 2009 CDC report:
- About half of IVF procedures in the U.S. involve the transfer of two embryos, 23% involve three, and around 10% involve four or five embryos.
- Close to 1 in 3 IVF births involves twins.
- 60% of IVF-related twin deliveries were preterm, compared to around 11% of single deliveries from single-fetus pregnancies.
“It is still common in the United States for doctors to transfer three or more embryos,” Romundstad says. “This study shows that three embryos does not result in more live births and it does result in more complications.”