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

Abstract

BackgroundIn the Netherlands, couples with unexplained infertility and a good prognosis to conceive spontaneously (i.e. Hunault > 30%) are advised to perform timed intercourse for at least another 6 months. If couples fail to conceive within this period, they will usually start assisted reproductive technology (ART). However, treatment of unexplained infertility by ART is empirical and can involve significant burdens. Intentional endometrial injury, also called ‘endometrial scratching’, has been proposed to positively affect the chance of embryo implantation in patients undergoing in vitro fertilization (IVF). It might also be beneficial for couples with unexplained infertility as defective endometrial receptivity may play a role in these women. The primary aim of this study is to determine whether endometrial scratching increases live birth rates in women with unexplained infertility.MethodA multicentre randomized controlled trial will be conducted in Dutch academic and non-academic hospitals starting from November 2017. A total of 792 women with unexplained infertility and a good prognosis for spontaneous conception < 12 months (Hunault > 30%) will be included, of whom half will undergo endometrial scratching in the luteal phase of the natural cycle. The women in the control group will not undergo endometrial scratching. According to Dutch guidelines, both groups will subsequently perform timed intercourse for at least 6 months. The primary endpoint is cumulative live birth rate. Secondary endpoints are clinical and ongoing pregnancy rate; miscarriage rate; biochemical pregnancy loss; multiple pregnancy rate; time to pregnancy; progression to intrauterine insemination (IUI) or IVF; pregnancy complications; complications of endometrial scratching; costs and endometrial tissue parameters associated with reproductive success or failure. The follow-up duration is 12 months.DiscussionSeveral small studies show a possible beneficial effect of endometrial scratching in women with unexplained infertility trying to conceive naturally or through IUI. However, the quality of this evidence is very low, making it unclear whether these women will truly benefit from this procedure. The SCRaTCH-OFO trial aims to investigate the effect of endometrial scratching on live birth rate in women with unexplained infertility and a good prognosis for spontaneous conception < 12 months.Trial registrationNTR6687, registered August 31st, 2017.Protocol versionVersion 2.6, November 14th, 2018.

Meta‐analysis of the embryo freezing transfer interval

“…On the other hand, excessively postponing ET could increase the stress and the anxiety that usually accompany IVF 47‐49 . Moreover, although only to a small extent, postponing ET contributes to increase the time to pregnancy, a parameter that is increasingly receiving attention as an important marker of the quality of IVF 50,51 …”

The definition of unexplained infertility: A systematic review

“…Of the remaining 375 papers, 117 did not classify a definition of unexplained infertility. As a result, a total of 258 primary research papers with full text available were included …”

Spontaneous pregnancies and determinant factors in infertility: A cross-sectional study

“…The small rate of SP in our study might have been affected by the environment, especially heat intensity, genetics, socioeconomic factors, nutrition, and obesity. On the other hand, many studies have been conducted for increasing fertility, for example, in a randomized controlled trial, the effect of endometrial scratching was conducted in couples with unexplained infertility and a good prognosis, and we must wait for their results (19).…”

“…No statistically significant relationship was observed between primary or secondary infertility with SP (p = 0.46). The rate of frequency of SP based on combined, unexplained, female, and male infertility causes were 45.2%, 25.8%,19.4%, and 9.7%, respectively. Interestingly, however, there was a statistically significant relationship between unexplained infertility and SP (p = 0.001).Table I.…”