Perinatal outcomes of singletons born following in-vitro fertilisation
Research type
Research Study
Full title
Perinatal outcomes of singletons born following in-vitro fertilisation: a comparison of different embryo transfer strategies using UK data.
IRAS ID
251442
Contact name
David McLernon
Contact email
Sponsor organisation
University of Aberdeen
Duration of Study in the UK
0 years, 11 months, 30 days
Research summary
Research Summary: Increasing numbers of infertile couples are undergoing in-vitro fertilisation (IVF) treatment in order to conceive. The treatment involves removing eggs from a woman’s ovaries and fertilising them in the laboratory to create embryos which are placed within the womb after either three or five days in the laboratory. Any remaining embryos are frozen for future use. Previous research has shown that IVF babies are less healthy than babies conceived naturally. Babies from frozen embryos are less likely to be premature but are heavier than those resulting from fresh embryos while those born from a five day old embryo are more likely to be premature than those from a three day old embryo. The accuracy of these results can be questioned because they are based on data which were unable to identify individual women who had more than one IVF baby following different types of embryo replacement from multiple treatments. We plan to analyse detailed UK IVF woman based records from mothers with one or more single-delivery IVF babies to investigate whether delayed transfer of embryos (five day replacement or freezing) results in a healthier baby.\nSummary of study results: Increasing numbers of infertile couples are undergoing in-vitro fertilisation (IVF) treatment in order to conceive. The treatment involves removing eggs from a woman’s ovaries and fertilising them in the laboratory to create embryos which are placed within the womb after either three or five days in the laboratory. Any remaining viable embryos may be frozen for future use. Previous research has shown that babies from frozen embryos are less likely to be premature but are heavier than those resulting from fresh embryos while those born from a five-day old embryo are more likely to be premature than those from a three-day old embryo. The accuracy of these results can be questioned because they are based on data which were unable to take into account women who had more than one IVF baby following different embryo replacement strategies. We analysed detailed HFEA data on all UK IVF records from mothers with one or more single-delivery IVF babies to investigate whether delayed transfer of embryos (five-day replacement or freezing) results in a healthier baby. Our key finding is that single babies born following a frozen embryo transfer are less likely to be small for gestational age than a singleton siblings born following a fresh embryo transfer, but are more likely to be large for gestational age. Single babies born following transfer of a fresh five-day old embryo were more likely to be large for gestational age (although the evidence was not that strong) but were less likely to have a congenital anomaly compared to siblings born following transfer of a fresh three-day old embryo. However, the absolute risks of any of these outcomes occurring are low and there is insufficient evidence to challenge the practice of extended culture of embryos.
REC name
Yorkshire & The Humber - Bradford Leeds Research Ethics Committee
REC reference
19/YH/0041
Date of REC Opinion
12 Feb 2019
REC opinion
Favourable Opinion