This is a cute story that caught my eye – a couple used in-vitro fertilization (IVF) to become pregnant, and they specifically asked their doctor to implant only one embryo to make sure that they did not have multiple births. In the end, that one embryo split twice, causing identical triplets to grow inside the uterus. All three baby boys were born healthy at 35 weeks gestation.
I asked Revolution Health fertility expert, Dr. Rani Abbasi, to help me to understand if there was any greater risk of twinning in the IVF process. Interestingly, there are some new techniques used to help insure implantation of embryos that can also increase the chances of identical twins forming. I don’t know if this couple’s doctor used either technique, but I thought I’d explain them to you because the MSNBC report might lead you to believe that this event was extremely rare (they quote 200 million to one) when in fact it may not be quite THAT rare.
There are two methods that fertility specialists can use to increase the chances of implantation for a single embryo. First, incubating the embryo in an extended culture (for 5 days rather than the usual 3) makes it more likely that the transfer will implant in the uterus. However, since the embryo is two days older at the time of transfer, it has a higher likelihood of splitting into two, causing identical twins.
Second, some fertility experts use a technique called “assisted hatching” which also improves the likelihood of implantation of an embryo. This involves making a small nick in the embryo’s outer zone (I think of it as an egg shell) to facilitate the cells breaking out of the protective outer coating and implanting in the uterine wall. When the nick is made, it is also possible for a single cell to fall out (rather than the group of cells, called a blastocyst, exiting together) and become its own fetus.
So ultimately, it’s possible that the techniques used by this couple’s doctor to insure a successful implantation of one embryo increased the chance of splitting of that same embryo, resulting in triplets. Granted, the chance of this happening is still rare – and it’s ironic since the couple was doing all they could to avoid twins or triplets – but it’s not nearly as rare as the chance of a random woman having identical triplets outside of IVF.
For more information about twins and triplets, check out my recent podcast interview with pregnancy expert Dr. Mary D’Alton. And for those of you who believe that you can control your destiny, this story should give you pause!This post originally appeared on Dr. Val’s blog at RevolutionHealth.com.