Recurrent implantation failure (RIF) means multiple embryo transfers — usually two or three, of reasonably good-quality embryos — haven't resulted in a pregnancy. It isn't a single disease with one fix; it's a signal to look more closely at the embryo, the uterus, and sometimes the immune or clotting factors that affect implantation, since any of these can be the reason a technically good embryo doesn't take.

What actually counts as "recurrent"

There's no single universal cutoff, and definitions vary between clinics and guidelines, but most consider RIF after two to three failed transfers of good-quality embryos (or a cumulative number of transferred embryos, since a single transfer may carry one or two embryos). What matters more than hitting an exact number is the overall pattern: were the embryos genuinely good quality, was the uterine lining adequately prepared each time, and is there a consistent reason transfers keep failing despite that.

What gets investigated

The embryo itself

Even an embryo that looks good under the microscope (good grading, reached blastocyst stage) can carry a chromosomal abnormality invisible without testing. If this hasn't already been checked, your doctor may discuss PGT-A (preimplantation genetic testing for aneuploidy) on future embryos, or review whether egg or sperm quality factors might be contributing.

The uterine cavity and lining

  • Hysteroscopy to directly look inside the uterus for polyps, fibroids, scar tissue (adhesions), or a uterine septum — any of which can physically interfere with implantation even when the embryo is fine
  • Endometrial thickness and pattern on ultrasound at the time of transfer
  • Chronic endometritis — a low-grade, often symptom-free uterine lining infection that can be checked for and treated with antibiotics if found

Hormonal and metabolic factors

  • Thyroid function (both underactive and overactive thyroid can affect implantation)
  • Prolactin levels
  • Vitamin D levels, which some clinics check as part of a broader workup

Immune and clotting factors

This is the most debated area of RIF workup. Some clinics test for thrombophilia (clotting tendency) or immune markers, and may consider treatments like blood thinners in selected cases — but the evidence for these tests and treatments is mixed, and not every fertility specialist recommends them routinely. This is worth a direct conversation about what your specific clinic recommends and why, rather than assuming every test offered is equally well-established.

Sperm factors

A detailed semen analysis, and sometimes a sperm DNA fragmentation test, if this hasn't already been done — sperm quality can affect embryo development even when fertilization itself succeeds.

Recurrent implantation failure is a prompt to investigate systematically, not a verdict that something is permanently wrong. Many couples who go through a structured workup go on to have a successful transfer once the specific factor is identified and addressed.

What changes after the workup

Depending on what's found, the next cycle might look different in several ways: a hysteroscopy to clear a polyp or adhesion before the next transfer, a change in endometrial preparation protocol, PGT-A testing on embryos before choosing which to transfer, or addressing a thyroid or vitamin D deficiency. Sometimes nothing specific is found, and the recommendation is simply to try again with closer monitoring — which can feel unsatisfying, but reflects that implantation genuinely isn't fully understood or predictable even with normal results across the board.

How this differs from recurrent pregnancy loss

Recurrent pregnancy loss is a related but distinct pattern — a pregnancy is confirmed and then lost, rather than an embryo failing to implant at all. The two workups share some of the same tests (uterine cavity assessment, clotting and hormonal panels), but implantation failure means a pregnancy was never detected in the first place, which points the evaluation more toward the embryo-uterus interaction at the moment of transfer. If you've experienced both patterns across different cycles, mention that clearly to your fertility team, since it shapes which tests are prioritised.

Frequently asked

How many failed transfers before it's actually called recurrent implantation failure?

Most definitions use two to three failed transfers of good-quality embryos, though this varies by clinic. One failed transfer on its own is common and not unusual — the RIF workup conversation typically starts after a pattern repeats.

Does recurrent implantation failure mean IVF won't work for us?

No. It means the usual approach hasn't worked yet, and a closer look is needed at why. Many couples with a RIF diagnosis do go on to have a successful pregnancy once the underlying issue (if one is found) is addressed.

Is a hysteroscopy always needed after repeated failed transfers?

It's one of the more commonly recommended steps because it directly checks for physical causes inside the uterus that an ultrasound can miss — see hysteroscopy: what it shows that an ultrasound can miss. Whether it's needed in your specific case depends on your history and your doctor's assessment.

Should every couple with RIF get immune or clotting tests done?

Not necessarily — this is one of the more debated parts of the workup, and not every fertility specialist orders these tests routinely, since the evidence supporting them is mixed. Ask your doctor specifically why a test is being recommended in your case, rather than assuming a longer test list is automatically more thorough.

Can PGT-A testing on embryos help after recurrent implantation failure?

It can help identify whether a chromosomal issue in the embryo is a factor, which is useful information even if it doesn't change every subsequent decision. See PGT-A and PGT-M, explained for what this testing can and can't tell you.