The PIP trial: no difference in live birth rate observed for patients undergoing endometrial scratching

1. This multicenter randomized control study showed that there were no significant differences in live birth rates between women undergoing in vitro fertilization (IVF) who had endometrial scratching performed prior to embryo transfer and women who had no intervention.

2. The scratch procedure was associated with mild pain and a small number of adverse events including intense pain, dizziness, nausea and bleeding.

Evidence Rating Level: 1 (Excellent)

Study Rundown: In vitro fertilization has gained momentum as a viable option for couples with infertility concerns. However, despite modern advancements in the procedure, success rates for IVF remain modest. Endometrial scratching with a pipelle has been proposed as a method to increase the success rate of IVF, however more data is needed to understand the effects of this procedure on live birth rates. In the Pipelle for Pregnancy (PIP) study, researchers examined the comparative effects of endometrial scratching versus no intervention on IVF live birth rates. The primary outcome was the live birth rate per woman in each study arm. Overall, researchers did not note any difference in live-birth rates between women who underwent endometrial scratching versus women who had no intervention. They also noted that women who had previously failed an IVF trial did not derive any marginal benefit from the procedure.

This large randomized trial concluded that there may not be much benefit derived from this procedure prior to embryo transfer, and the robust subgroup analysis showing no specific patient populations benefiting from the procedure further supports this conclusion. Notable limitations include lack of recording of pain scores during procedures in the control group and infeasibility to blind study participants.

Click to read the study in NEJM

Click to read an accompanying editorial in NEJM

Relevant Reading: The effect of endometrial injury on ongoing pregnancy rate in unselected subfertile women undergoing in vitro fertilization: a randomized controlled trial

In-Depth [randomized controlled trial]: This international, randomized control trial enrolled a total of 1364 women undergoing IVF to either an endometrial scratch group (n=690) or a control group (n=674) between 2014 to 2017. Exclusion criteria included women not planning an embryo transfer, contraindications to a scratching procedure, and recently undergoing any disruptive uterine procedure. Of the trial participants, 586 (84.9%) of women in the endometrial scratch group and 532 (78.9%) underwent embryo transfer. Women who underwent the endometrial-scratch procedure had a median pain score of 3.5 on a 10-point pain scale (interquartile range, 1.9 to 6.0). The live-birth rate was 26.1% (180/690) in the endometrial scratch group and 26.1% (176/674) in the control group (adjusted odds ratio [aOR], 1.00; 95% confidence interval [CI], 0.78 to 1.27; P=0.97). Among secondary outcomes, no between-group difference was observed for rates of ongoing pregnancy, clinical pregnancy, multiple pregnancy, ectopic pregnancy, or miscarriage. There was also no evidence to suggest that endometrial scratching benefited women who had failed at least two previous IVF trials versus women who failed no more than one trial (interaction OR, 0.63; 95% CI, 0.35 to 1.15; P=0.14). No subgroup analysis indicated any between-group difference regarding live birth rate outcomes. Fourteen women in the endometrial scratch group experienced adverse events including excessive pain (n=5), dizziness or nausea (n=7) and excessive bleeding (n=2).

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