Endometrial receptivity testing
The marketing rests on an analysis the trial's own abstract describes as showing no difference.
The claim is that a timed biopsy of the womb lining, profiled for gene expression, identifies your individual "window of implantation", which in roughly a third of women is displaced, and that adjusting the timing of transfer accordingly raises live birth.
The trial it is marketed on. 458 patients randomized across 16 clinics. The published abstract states plainly: Clinical outcomes by intention-to-treat analysis were comparable.
The favourable figures used in marketing come from a per-protocol analysis in a trial that lost 50% of patients to drop-out against 30% planned. A per-protocol analysis in an open-label trial losing half its patients is the design most likely to manufacture an effect out of nothing.
The trial that tested it properly. Double-blind, 30 US sites, 767 patients who had all undergone IVF, embryo screening, and receptivity testing. The control group was transferred at standard timing regardless of their receptivity result. 98% completed.
| Outcome | Timed by the test | Standard timing | Difference (95% CI) |
|---|---|---|---|
| Live birth | 58.5% (223 of 381) | 61.9% (239 of 386) | −3.4 points (−10.3 to +3.5) |
| Clinical pregnancy | 68.8% | 72.8% | −4.0 points |
| Biochemical pregnancy | 77.2% | 79.5% | −2.3 points |
Every point estimate favoured not testing. The authors' conclusion: The findings do not support routine use of receptivity testing to guide the timing of embryo transfer during in vitro fertilization.
A systematic review found no important differences in live birth or clinical pregnancy in women without recurrent implantation failure, at moderate certainty, and concluded that the evidence precludes the routine use of this strategy
in that group. In women with recurrent implantation failure, only low-certainty observational evidence exists and no randomized trial has been published at all.
may reduce treatment effectiveness.Red here does not mean unproven. It means the evidence points the wrong way.