MedPage Today (subscription required) carried a brief notice on May 22 regarding single embryo transfer in IVF. What follows is directly cribbed from that article. Key points:
- IVF pregnancies are higher risk than naturally-conceived pregnancies. (No further details were cited.)
- Most embryo transfers involve one or two embryos.
- Transfer of two embryos is generally driven by fear of failure to conceive with only one. (I don’t find that surprising.)
- About 30% of IVF births are twins (still), compared to about 2% naturally. (By the way, the article used “natural”—it’s not just my chosen term.)
- Many IVF programs are now mandating transfer of only a single embryo, with the support of their patients.
- Recently-published data show that live birth rates with two cycles of single embryo transfer are as good as or better than one cycle of transfer of two embryos. Two cycles of single embryo transfer is associated with a 1-3% incidence of twins (identical, from splitting of the single embryo).
- It’s been demonstrated elsewhere that transfer or two or more embryos is associated with risks including low birth weight, increased risk of prematurity or miscarriage, or cognitive or developmental impairment of the born child (or children). (I infer that “embryo reduction”—that is, abortion of all but one transferred embryo—may be in view here.)
- “Success for modern IVF should be defined as a singleton pregnancy that results in a healthy singleton infant who is born at term.” (Quote and emphasis from the MedPage description of the single vs double embryo transfer study.)
- Cost and insurance coverage remain barriers to exclusive use of single embryo transfer.
No further discussion for now. I’ll leave that for the comments section.