Clinical pearls:
- Current research points in favor of performing endometrial scratching between day 7 of previous cycle to day 7 of the embryo transfer cycle resulting in improvement in clinical pregnancy rate and live birth rates in women with more than two previous embryo transfers.
It is
proposed that endometrial scratching or biopsy increases the chances of implantation
in women attempting ARTs. With an intention to determine the current practice clinicians
across Australia, New Zealand and the UK were given an on-line survey between
August to October 2015. The results of this
study was published in the recent issue of Human Reproduction.[1]
In this cross-
sectional study spanning 143 private and public fertility centers, 89% of
physicians, embryologists and nurses perform the endometrial biopsy or
scratching as a part of treatment protocols for couples undergoing IVF.[2]
The most
common indication (92%) for the procedure was Recurrent Implantation failure
(RIF) while only 3.6% clinicians offered it to patients trying to conceive by
natural intercourse or IUI. Although many trials exist documenting the benefit
of this procedure in couple trying to conceive naturally. [3]
It was interesting
to see that they all followed different time frame for doing the procedure.
89% of the
centers offered the procedure in the luteal phase of the cycle prior to the
embryo transfer cycle and none performed it on the day of egg retrieval or
embryo-transfer.
Two- thirds
of the responders agreed that it is very useful in RIF undergoing IVF and more
than 50% did not think it to be useful before the first IVF cycle.
Currently the
most accepted explanation for the success is favorable immune modulation of the
endometrium increasing the implantation rate. Other theories are it modulates
the gene expression and increases the receptivity. [4]
A review of
literature finds many RCTs conducted in the past to gauge the benefit of the
procedure.
Results of Cochrane
systemic review of 14 Randomized control trial(RCTs) shows that endometrial injury
before starting the ovarian stimulation improves the chances of conception and
ongoing pregnancy.[5] The
evidence is moderate grade and suggests that “Endometrial injury performed
between day 7 of the previous cycle and day 7 of the embryo transfer (ET) cycle
is associated with an improvement in live birth and clinical pregnancy rates in
women with more than two previous embryo transfers.”
With all
these evidence pointing in favor of the procedure, a very large and robust
study with sufficient power by Yeung et al[6]
published in Human Reproduction showed that the procedure does not offer any
benefits contrary to the previous beliefs. But, in this study about 70% of the patients
received the procedure in their first IVF cycle so the results may not be
generalized to patients with RIF.
To conclude,
although current evidence is in favor of endometrial scratching, more evidence
is needed in the form of large, randomized clinical trials regarding its timing
in relation to menstrual cycle, use in women with or without RIF and its use in
natural cycles, before this inexpensive and simple procedure can be widely
applied in fertility clinics.
[1] http://humrep.oxfordjournals.org/content/31/6/1241.abstract
[2] http://humrep.oxfordjournals.org/content/31/6/1241.full.pdf+html
[3] Gibreel
A, Badawy A, El-Refai W, El-Adawi N. Endometrial scratching to improve
pregnancy rate in couples with unexplained subfertility: a randomized
controlled trial. J Obstet Gynaecol Res 2013;39:680 – 684.
[4]
Zhou L,Li R, Wang R, Huang H-x, Zhong K. Local injury
to the endometrium in controlled ovarian hyperstimulation cycles improves
implantation rates. Fertil
Steril2008;89:1166-1176.
[5] http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009517.pub3/pdf
