A major clinical trial presented at a leading fertility conference has found that four cycles of artificial insemination with hormone treatment did not match a single full cycle of IVF for achieving a live birth.
The FIIX trial, presented at the American Society for Reproductive Medicine (ASRM) 2026 annual meeting and published in the New England Journal of Medicine, tested a common assumption in fertility care — that starting with less intensive treatments before moving to IVF produces comparable results. For couples with unexplained infertility, it appears that may not be the case.
The trial compared four cycles of intrauterine insemination (IUI) — where sperm is placed directly into the womb — combined with ovarian stimulation (hormone medication to encourage egg production) against one complete cycle of in vitro fertilisation (IVF), where eggs are fertilised outside the body and an embryo is transferred back. The measure used was cumulative live-birth rate: the proportion of couples who ultimately had a baby.
According to the trial results, IUI with ovarian stimulation failed to meet the threshold for non-inferiority — meaning it could not be shown to be close enough in effectiveness to IVF. In plain terms, starting with repeated IUI cycles did not deliver the same chance of a live birth as going straight to IVF.
That’s a finding that could reshape how fertility specialists sequence treatment for couples where no clear cause of infertility has been identified — a group that makes up a major proportion of those seeking help.
The New England Journal of Medicine is one of the most widely cited medical journals in the world, and ASRM is the principal professional body for reproductive medicine in the United States. Results presented at its annual meeting typically carry weight in clinical practice internationally.
Anyone with concerns about fertility should speak to their GP in the first instance. NHS 111 can also provide guidance on accessing fertility services.
Source: @NEJM