(HealthDay)—For women undergoing in vitro fertilization (IVF), endometrial scratching by pipelle biopsy between day 3 of the cycle preceding the embryo-transfer cycle and day 3 of the embryo-transfer cycle, does not result in a higher rate of live birth, according to a study published in the Jan. 24 issue of the New England Journal of Medicine.

Sarah Lensen, Ph.D., from the University of Auckland in New Zealand, and colleagues conducted a pragmatic multicenter trial involving 1,364 undergoing IVF (fresh embryo or frozen-embryo transfer) with no recent exposure to disruptive intrauterine instrumentation. Participants were randomly assigned to endometrial scratching (690 women) or no intervention (674 women).

The researchers found that the frequency of live birth was 26.1 percent in both the endometrial-scratch and control groups (adjusted odds ratio, 1.00; 95 percent confidence interval, 0.78 to 1.27). The rates of ongoing , clinical pregnancy, multiple pregnancy, , or miscarriage did not differ significantly between the groups. For scratching, the median score for pain was 3.5 on a scale of 0 to 10 with higher scores indicating worse pain.

"Endometrial scratching did not result in higher rates of the primary outcome of live birth than no procedure in intention-to-treat or in post hoc per-protocol analyses," the authors write. "Subgroup analyses did not identify any populations of women who might benefit."