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Endometrial Scratching Before IVF Fails to Improve Birth Rates

Endometrial scratching before vitro fertilization (IVF), while intended to improve pregnancy, did not improve live birth rates, a randomized trial found.

The intervention yielded a live birth in 26.1% of women compared with 26.1% among controls (adjusted OR 1.00, 95% CI 0.78-1.27), reported Sarah Lensen, PhD, of the University of Auckland in New Zealand, and colleagues.

Moreover, there were no significant differences in other pregnancy outcomes, such as rates of clinically-confirmed pregnancy, carriage for at least 20 months, ectopic pregnancy, or miscarriage, the authors wrote in the New England Journal of Medicine in line with what was presented in July at the European Society of Human Reproduction and Embryology (ESHRE) meeting.

An accompanying editorial by Ben W. Mol, MD, of Monash University in Victoria, Australia, and Kurt T. Barnhart, MD, of the University of Pennsylvania in Philadelphia, pointed out that not only did the trial fail to meet the primary outcome, but showed no “suggestion of benefit” in any examined secondary outcome.

The technique used reflects current standards of care, and the population — which included both women undergoing IVF for the first time and women with previous failed cycles, treated in centers in several countries — was generalizable to populations with infertility across the world, they wrote. “As a consequence, the results of this trial should be trusted.”

A recent survey found that 83% of fertility clinicians in the U.K., Australia, and New Zealand offer or recommend endometrial scratching, which can cost patients up to approximately $500.

A 2016 Cochrane review suggested an increased probability of clinical pregnancy with endometrial scratching, but Lensen’s group warned most of the trials included had a high risk of bias. Mol and Barnhart assessed the quality of evidence as “moderate,” noting a host of limitations, including “not prospectively registered, showed unrealistic large effect sizes in limited sample sizes, used suboptimal randomization techniques, or were stopped prematurely.”

Moreover, Mol and Barnhart said that Lensen’s “well-conducted” trial reinforced the idea that all adjuvants to fertility treatments and IVF should be carefully evaluated prior to being offered to patients who “may be receptive to anything that might hypothetically increase their chance of having a baby.”

“An unanswered public health question is whether IVF clinics and doctors around the world should continue to offer unevaluated adjuvants, recognizing the likelihood that they will be proven ineffective once properly evaluated and that some might cause harm,” the editorialists wrote.

“Misleading information on the effectiveness of adjuvants is already the topic of legal disputes involving couples who have used IVF,” they added, referring to a couple who became the first in the U.K. to sue an IVF clinic for upselling them “worthless and unproven” extra interventions.

Lensen and colleagues randomized 1,364 women to receive endometrial scratching between day 3 of the cycle preceding the IVF cycle and day 3 of the IVF cycle or to serve as controls who did not receive the intervention. There was no significant difference between groups in live birth or any examined pregnancy outcome.

In addition, there was no evidence of benefit among women in whom implantation had failed at least twice or among women in whom it had failed no more than once, the authors said — writing that “subgroup analyses did not identify any populations of women who might benefit.”

The study was supported by the University of Auckland, the A+ Trust, the Auckland District Health Board, the Nurture Foundation, and the Maurice and Phyllis Paykel Trust.

Lensen disclosed no conflicts of interest.

Co-authors disclosed support from Ferring Pharmaceuticals, Bart’s Charity, Finox Pharmaceuticals, and Pharmasure Pharmaceuticals.

Mol disclosed support from Merck, Guerbet, and ObsEva.

Barnhart disclosed no conflicts of interest.