What is endometrial scratching – Indications and procedure

By (gynecologist) and BSc, MSc (embryologist).
Last Update: 06/08/2021

Endometrial curettage, technically known as endometrial scratching, is a simple surgical procedure in which a small amount of damage is caused to the inner wall of the uterus (the endometrium) with the aim of regenerating it and increasing its receptivity.

Therefore, endometrial scratching is intended for patients who fail to achieve pregnancy due to repeated implantation failures, in whom no other more likely cause of infertility has been found.

Definition of endometrial curettage

Endometrial scratching is a light scraping of this mucous layer that lines the inside of the uterus and is where the implantation of the embryo takes place.

The aim of this is to allow the endometrium to regenerate properly, to increase its receptivity and to increase the probability of pregnancy in women.

This is a new process that more and more assisted reproduction clinics are incorporating every day due to its simplicity and good results.

Types

The procedure for endometrial scratching is very simple, takes about 15-20 minutes and can be done using two techniques:

Hysteroscopy
is a diagnostic test to visualize the inside of the uterus by introducing an optical system through the cervix. Once the specialist is assessing the uterine cavity, he can take the opportunity to scrape the walls of the uterus. Hysteroscopy has the advantage that polyps, adhesions or uterine malformations that could be interfering with embryo implantation can also be found.
Endometrial biopsy
is a procedure very similar to embryo transfer after in vitro fertilization (IVF). A flexible catheter is passed through the cervix and the endometrium is gently scraped. To perform an endometrial biopsy it is not necessary to apply anesthesia, since it is painless.

After endometrial curettage, the woman can go on with her normal life, although it is common for a small amount of bleeding to appear.

Most commonly, scratching is done by endometrial biopsy, although if the woman must have a hysteroscopy for other reasons, this technique would be used.

When is it done?

Endometrial scratching should be performed during the luteal phase of the menstrual cycle, that is, around day 21 of the cycle if the woman is regular.

Normally, in patients who are going to undergo IVF, this endometrial curettage is done in the previous cycle.

The same happens if the woman is going to have a transfer of frozen embryos or embryos from ovodonation. The endometrial scratching would be done in the cycle before the embryo transfer.

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Indications

Endometrial scratching is indicated for IVF patients who have suffered repeated implantation failures, i.e. after several embryo transfers have not achieved a positive result despite having good quality embryos.

Specifically, a woman or couple is considered to have implantation failure when two or more good quality embryo transfers have been performed without achieving pregnancy.

In principle, the problem does not come from the gametes (eggs and sperm) of the parents, since the embryos are of apparently good quality. Therefore, the failure can be attributed to problems in the communication between the embryo and the uterus.

If the endometrium is not receptive after the transfer, the embryo will not be able to nest in it and the implantation that initiates gestation will not be able to take place.

If you want to read more about this freezing technique, you can access the following post: Repeated embryo implantation failures - Reasons Why Embryos Don't Implant.

Advantages of endometrial scratching

It is not yet clear why endometrial curettage has the ability to increase the rate of embryo implantation, but studies suggest that scraping the endometrium elicits an inflammatory response similar to a scratch on the skin.

The repair process that occurs in the endometrium after this intentional damage would increase the chances of implantation mainly for these two reasons:

  • The injury promotes the release of growth factors, chemicals and hormones that allow the endometrium that grows in the next cycle to do so in a more receptive way and, therefore, the endometrium-embryo connection is improved.
  • The scraping could also activate genes responsible for implantation that in some "common" transfers (without scraping) are not activated and that can be of great help for the embryo to implant.

Risks and side effects

In general, endometrial curettage is a safe technique that has almost no adverse effects.

However, it is common for women to have slight bleeding after the procedure and to suffer from abdominal cramps.

In very rare cases, there may be a pelvic infection or uterine perforation as a result of endometrial scratching.

Finally, it is worth mentioning that endometrial curettage would cause a miscarriage if the woman were pregnant. To be sure of this, the gynecologist will first check that there is no evidence of a gestational sac by ultrasound.

FAQs from users

What are the benefits of endometrial scratching?

By Dra. Lydia Pilar Suárez (gynecologist).

Endometrial scratching is a relatively new, simple technique that provides good results in assisted reproduction techniques.

It is applied mainly in patients diagnosed with recurrent implantation failure to improve the reception site of a new embryo.

The objectives of endometrial scratching are:

  • To produce a small lesion in the endometrium that causes growth factors, hormonal and chemical factors to be released, so that the newly growing endometrium becomes more receptive.
  • Potential activation of molecular/genetic factors involved in implantation that would not be activated in a normal transfer.

At present, scratching is considered to be a good solution for patients with previous implantation failures in order to increase their gestation rate, although there is still no evidence for its routine recommendation.

Does endometrial scratching hurt?

By Zaira Salvador BSc, MSc (embryologist).

No, endometrial scratching does not hurt and therefore anaesthesia is not necessary. The woman may feel some discomfort during the procedure when the catheter is inserted through the cervix, but nothing more.

Will I be able to get pregnant after endometrial scratching?

By Zaira Salvador BSc, MSc (embryologist).

Endometrial curettage may be the solution to achieve pregnancy especially for patients with previous implantation failure. Scientific studies show that it is an effective technique for this group of patients.

In addition, there are also promising studies suggesting an increased implantation rate in patients who undergo other assisted reproductive techniques in addition to IVF.

Do I need to take any special care after endometrial scratching?

By Zaira Salvador BSc, MSc (embryologist).

In principle, no. The woman can live a normal life after the operation, bearing in mind that she may bleed a little, so it is advisable to wear a sanvaslip or sanitary towel (a tampon is not recommended).

The doctor may also give some instructions, for example, not to have sexual intercourse that night.

Suggested for you

Throughout the article we have talked about embryo implantation, but if you want to know all the details of this particular process in which a pregnancy begins, we encourage you to continue reading here: What are the Different Stages of Embryo Implantation?

You can also learn more about endometrial receptivity in the following article: Uterine Receptivity As a Cause of Sterility.

Our editors have made great efforts to create this content for you. By sharing this post, you are helping us to keep ourselves motivated to work even harder.

References

Bashiri A, Halper KI, Orvieto R. Recurrent Implantation Failure-update overview on etiology, diagnosis, treatment and future directions. Reprod Biol Endocrinol. 2018 Dec 5;16(1):121.

Bord I, Tamir B, Harlev A, Har-Vardi I, Lunenfeld E, Friger M, Levitas E. Recurrent implantation failure in IVF: features of cycles that eventually ended in conception. Arch Gynecol Obstet. 2016 Apr;293(4):893-900.

Bui BN, Torrance HL, Janssen C, Cohlen B, de Bruin JP et al. Does endometrial scratching increase the rate of spontaneous conception in couples with unexplained infertility and a good prognosis (Hunault > 30%)? Study protocol of the SCRaTCH-OFO trial: a randomized controlled trial. BMC Pregnancy Childbirth. 2018 Dec 29;18(1):511.

Gibreel A, El-Adawi N, Elgindy E, Al-Inany H, Allakany N, Tournaye H. Endometrial scratching for women with previous IVF failure undergoing IVF treatment. Gynecol Endocrinol. 2015 Apr;31(4):313-6.

Levin D, Hasson J, Cohen A, Or Y, Ata B, Barzilay L, Almog B. The effect of endometrial injury on implantation and clinical pregnancy rates. Gynecol Endocrinol. 2017 Oct;33(10):779-782.

van Hoogenhuijze NE, Torrance HL, Mol F, Laven JSE, Scheenjes E et al. Endometrial scratching in women with implantation failure after a first IVF/ICSI cycle; does it lead to a higher live birth rate? The SCRaTCH study: a randomized controlled trial (NTR 5342). BMC Womens Health. 2017 Jul 21;17(1):47.

FAQs from users: 'What are the benefits of endometrial scratching?', 'Does endometrial scratching hurt?', 'Will I be able to get pregnant after endometrial scratching?' and 'Do I need to take any special care after endometrial scratching?'.

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Authors and contributors

Dra. Lydia Pilar Suárez
Dra. Lydia Pilar Suárez
Gynecologist
Bachelor degree in Medicine and Surgery at the Universidad de Oviedo in Asturias. Specialization in Obstetrics and Gynecology at the University Hospital of San Carlos de Madrid. Master in Assisted Reproduction at the University of Rey Juan Carlos in collaboration with the Valencian Fertility Clinic IVI. More information about Dra. Lydia Pilar Suárez
Licence number: 64136
 Zaira Salvador
Zaira Salvador
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Technical University of Valencia (UPV). Biotechnology Degree from the National University of Ireland en Galway (NUIG) and embryologist specializing in Assisted Reproduction, with a Master's Degree in Biotechnology of Human Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI) More information about Zaira Salvador
License: 3185-CV

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