Implantation is the process by which an embryo, usually at the blastocyst stage, attaches to and burrows into the endometrium (uterine lining), typically five to seven days after fertilisation. This is the step at which a pregnancy is biologically established; a positive pregnancy test reflects implantation having occurred, not the embryo transfer procedure itself. Embryo transfer — placing an embryo into the uterine cavity during IVF or a frozen embryo transfer — is not the same as implantation. Transfer is a mechanical procedure performed by the clinical team; implantation is a biological process that follows, and may or may not succeed even when the transfer itself goes smoothly. Factors affecting implantation include embryo quality, endometrial receptivity and thickness, and uterine cavity conditions.
Also known as: embryo implantation, implanted, did the embryo implant
Related India guides
Sources
- Indian Council of Medical Research (icmr.gov.in)
- Federation of Obstetric and Gynaecological Societies of India (fogsi.org)
Last reviewed: 9 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.