A multiple birth can be a frightening prospect for women receiving fertility treatments. Many patients at New York fertility clinics are already aware of the heightened risk of multiple births—especially for women receiving IVF treatment.
While a multiple birth can ultimately be a blessing, there are undoubtedly many risks associated with carrying more than a single baby. These risks include a higher rate of delivery by cesarean section, preeclampsia, and miscarriage, among others.
In recent years, fertility clinics have worked to reduce the rate of multiple births associated with fertility treatment. Here are three of the most successful ways physicians have reduced the number of multiples:
1. Reducing the number of transferred embryos
Decades ago, IVF required more embryos to be inserted because the success rate was lower. According to the New York Times, the number of IVF treatments that transferred four or more embryos dropped from 62 percent in 1996 to 21 percent in 2004. Improved IVF techniques have yielded stronger embryos, reducing the need to transfer so many.
Today, for a patient that is under 35 years old, physicians rarely transfer more than two embryos during an IVF cycle. This reduces the chance for a risky multiple gestation.
2. Multiple IVF cycles and freezing
Single embryo transfer is ideal for reducing the risk of multiples. However, single-embryo transfer has a lower rate of success.
If a patient agrees to two cycles of IVF, a single embryo can be transferred, while a second embryo is frozen. If the first cycle of IVF fails, the second embryo can be transferred later. Transferring a single embryo is a less costly process, and this approach boasts similar success rates to transferring two embryos at a time, while nearly eliminating the risk of a multiple gestation.
3. Improved embryo selection
In order to increase the chances of a successful transfer in a single-embryo IVF cycle, physicians must select the embryo most likely to survive.
Some of the criteria physicians use to select the most viable embryos include:
- Number of divisions
- Chromosomal abnormalities
- Genetic screening
Examining these criteria helps physicians to select the most viable embryos, which increases the likelihood of success in single-embryo transfer.
These techniques have combined in recent years to improve the viability of single-embryo transfer in IVF. While there are many factors that can affect how many embryos should be transferred, single-embryo transfer drastically reduces the chance of a multiple birth.
Single-embryo transfer is not only less costly than multiple-embryo transfers, but it also greatly reduces the risk of complications arising from multiple gestations during pregnancy. Any woman who is concerned about the risk of multiple births should discuss this option with her physician.