(PROST) A form of assisted conception in which in vitro fertilisation (IVF) is used to produce fertilisation of one or more recovered eggs (oocytes). Useful if the potential fertilising ability of sperm (spermatozoa) is in doubt. Transfer is made on the day after egg retrieval and IVF, before the fertilised egg divides (it's at the pronuclear stage); the transfer is made to the fallopian tube to obtain advantages similar to gamete intrafallopian transfer (GIFT) and is made possible by laparoscopy (with anesthesia) or, less successfully, by transvaginal ultrasound (without anesthesia). Synonymous with zygote intrafallopian transfer (ZIFT).