Implantation — the embryo attaching to the uterine lining — is the step of IVF that medicine can least directly control. Recurrent implantation failure describes the situation where seemingly good-quality embryos have been transferred over multiple cycles without a pregnancy resulting.
Where doctors look
Investigation works through three areas: the embryo (chromosomal status, which becomes more significant with age; genetic testing may be discussed), the uterus (polyps, fibroids, adhesions, chronic endometritis — often checked by hysteroscopy), and the receptivity of the lining itself, including its thickness and timing. Blood conditions affecting clotting or immunity are also considered.
The outlook
RIF is frustrating precisely because each attempt looked right. But a structured re-evaluation often finds something adjustable — and many couples labelled with RIF do go on to a successful transfer once the underlying factor is addressed.