Timing of Endometrial Injury Matters in ART

In women undergoing assisted reproductive techniques (ART), intentional endometrial injury performed in the month prior to the embryo transfer cycle can increase the likelihood of clinical pregnancy and live birth, according to results of a new study.¹

Intentionally injuring the endometrium through endometrial biopsy or curettage before embryo transfer has been reported previously to increase the odds of implantation and aid embryonic development, subsequently improving the chances of a live birth.^2,3 The hypothesis behind this practice is that injury to the endometrium triggers a large secretion of growth factors and cytokines in the process of wound healing, which may help implantation.² However, the effectiveness and safety of this practice remains unknown.

Using 5 randomized controlled trials that compared intentional endometrial injury prior to embryo transfer in women undergoing ART with no intervention or with a mock procedure that did not cause endometrial injury, researchers assessed the efficacy and safety of the practice. A total of 591 women were included. In a subgroup analysis, outcomes were compared for injury in the previous cycle and injury on the day of oocyte retrieval.

In the previous-cycle subgroup, the procedure for intentional injury was performed within 1 month before the start of ovulation induction. The intervention more than doubled the chances of a clinical pregnancy (4 trials; OR, 2.61) and a live birth (2 trials; OR, 2.46).1 There were no reports of pain or bleeding in any of the 4 trials. Imprecise reporting of the odds of miscarriage per clinical pregnancy prevented the authors from developing any meaningful conclusion about the relationship between intentional endometrial injury and miscarriage.

In the day-of-oocyte-retrieval subgroup, endometrial injury occurred a few days before the embryo was transferred to the uterus. The odds of clinical pregnancy (1 trial; OR, 0.30) and ongoing pregnancy were significantly reduced (1 trial; OR, 0.28).¹ As with the trials used in the previous-cycle subgroup, the trial for the day-of subgroup did not report adverse effects related to the practice.

To better understand the safety of endometrial injury, future studies should assess whether the practice is associated with adverse effects, such as pain and bleeding, and how the practice relates to multiple pregnancy or miscarriage.

Pertinent Points:
- Endometrial injury performed in the month before starting ovulation induction improves the rates of clinical pregnancy and live birth in women undergoing assisted reproductive techniques.
- Performing endometrial injury on the day of oocyte retrieval significantly reduces the rates of clinical pregnancy and ongoing pregnancy.
 

References:

1. Nastri CO, Gibreel A, Raine-Fenning N, et al. Endometrial injury in women undergoing assisted reproductive techniques. Cochrane Database Syst Rev. 2012;7:CD009571.
2. Barash A, Dekel N, Fieldust S, et al. Local injury to the endometrium doubles the incidence of successful pregnancies in patients undergoing in vitro fertilization. Fertil Steril. 2003;79:1317-1322.
3. Narvekar SA, Gupta N, Shetty N, et al. Does local endometrial injury in the nontransfer cycle improve the IVF-ET outcome in the subsequent cycle in patients with previous unsuccessful IVF? A randomized controlled pilot study. J Hum Reprod Sci. 2010;3:15-19.