Editing In vitro fertilisation (section)

===Embryo transfer===
{{Main|Embryo transfer}}
The number to be transferred depends on the number available, the age of the patient and other health and diagnostic factors. In countries such as Canada, the UK, Australia and New Zealand, a maximum of two embryos are transferred except in unusual circumstances. In the UK and according to [[HFEA]] regulations, a woman over 40 may have up to three embryos transferred, whereas in the US, there is no legal limit on the number of embryos which may be transferred, although medical associations have provided practice guidelines. Most clinics and country regulatory bodies seek to minimise the risk of multiple pregnancy, as it is not uncommon for multiple embryos to implant if multiple embryos are transferred. Embryos are transferred to the patient's uterus through a thin, plastic [[catheter]], which goes through their [[vagina]] and cervix. Several embryos may be passed into the uterus to improve chances of [[Implantation (human embryo)|implantation]] and pregnancy.<ref>{{cite journal | vauthors = Timeva T, Shterev A, Kyurkchiev S | title = Recurrent implantation failure: the role of the endometrium | journal = Journal of Reproduction & Infertility | volume = 15 | issue = 4 | pages = 173–183 | date = October 2014 | pmid = 25473625 | pmc = 4227974 }}</ref><ref>{{Cite web|title=In vitro fertilization (IVF) – Mayo Clinic|url=https://www.mayoclinic.org/tests-procedures/in-vitro-fertilization/about/pac-20384716|access-date=31 August 2020|website=www.mayoclinic.org}}</ref>