Some fertility treatments, such as IVF, might increase the possibility of having twins due to multiple embryos being transferred or the spontaneous splitting of one embryo. But it’s much more likely that you carry just one baby to term.
The primary cause of multiple births with in vitro fertilization (IVF) is the transfer of more than one embryo.
Doctors, however, are pivoting away from this and limiting the number of embryos they transfer (usually one carefully selected embryo).
While the chance of multiple births due to IVF remains low, it is still higher than the rate of twins or more from a natural pregnancy.
As science and technology evolve, such cases of multiple births are on the decline.
Between 2007 and 2008, becoming pregnant with at least twins due to IVF occurred in almost 1 in 4 cases. But from 2021 to 2022, this rate decreased to about 1 in 12.
Your chances of carrying a single baby to term by means of IVF are much higher, at just about 42% if a female partner is younger than 35.
In the past, doctors commonly transferred three embryos into a uterus to increase the chance of pregnancy. The transfer of multiple embryos was the primary cause of multiple births.
However, as the transfer of one embryo is becoming more standard, the rate of multiple pregnancies is decreasing.
Another potential cause of having twins through IVF is the spontaneous (random) splitting of one of the embryos. This could result in two embryos, causing twins.
Doctors can reduce the chance of having multiple babies by limiting the number of embryos transferred to the uterus at one time.
Today, health professionals more often select one healthy and strong embryo to transfer (instead of two or more), called single embryo transfer, for women younger than 35 years and in otherwise good health.
Still, it’s important to recognize that the slight chance of having twins or more is part of the process that can lead to a successful pregnancy.
It’s possible that IVF can lead to becoming pregnant with twins or more, but it’s unlikely, especially as science and technology improve.
Compared to the past, doctors today primarily transfer one embryo during IVF rather than two or more (which was done to help increase chances of pregnancy). But the one embryo they transfer is carefully selected.
Speak with your doctor about which fertility treatment might be right for you if you wish to become pregnant.