About 6% of married couples in the United States report infertility. Many of these 1.5 million couples seek help from OBGYNs and fertility specialists. The world of "Assisted Reproductive Techniques" (ART) offers many high-tech options. Fertility treatments can include anything from medications to in vitro fertilization (implanting an embryo into the uterus). A Cochrane review and new meta-analysis bring to light a very simple office procedure that may double the chances of getting pregnant: endometrial scratching.
The endometrium is the inner lining of the uterus. When an embryo is in the uterus (by spontaneous conception, IVF, etc...), it must implant into the wall of the uterus. The embryo embeds itself into the uterine wall so that it can grow into a successful pregnancy. This first step is critical since without implantation, there is no pregnancy. Endometrial scratching is a process of causing a minor injury to the uterine wall. It can be accomplished by lightly scraping the inner wall of the uterus with a sharp, thin tool called a curette. Another method of endometrial scratching is endometrial biopsy. The doctor inserts a thin pipette into the uterus and uses suction to pull off a small piece of the wall with the pipette.
How does causing injury to the uterine wall promote implantation? Doctors theorize that the injury causes some inflammation in the endometrium. The inflammation may trigger increased blood flow or other chemical or hormonal factors to release. Perhaps the injury causes a mechanical or physical change that makes the lining more receptive. Whatever the underlying mechanism, after the injury, the endometrium seems to be more receptive to implantation of an embryo.
Cochrane researchers studied 14 clinical trials including 2,128 women with infertility undergoing IVF. In 13 of the studies, doctors performed endometrial scratching during the menstrual cycle before attempting to transfer an embryo into the uterus. In the last study, doctors performed endometrial scratching a few days before the embryo was transferred into the uterus. In the 13 studies with endometrial scratching in the month before embryo transfer, endometrial scratching improved the odds of pregnancy and live birth. Without embryo scratching, about 26% of women achieve a live birth after ART. With endometrial scratching, the percentage of live birth increased to 28-48%. Endometrial scratching a few days before embryo transfer had the opposite effect: pregnancy rates were lower.
Dr. Sarah Lensen and her colleagues conducted a new meta-analysis of eight trials and 1,180 women. The meta-analysis supports the findings of the Cochrane Review. Endometrial scratching was studied in women attempting to conceive spontaneously, with the aid of medications (ovulation induction), or with intrauterine insemination (insertion of sperm directly into the uterus). The chances of live birth or ongoing pregnancy increased from 9% without endometrial scratching to 14-28% with endometrial scratching. These statistics indicate that endometrial scratching could double the chances of pregnancy.
The Cochrane review was unable to make firm conclusions about side effects like miscarriage or vaginal bleeding. In the new meta-analysis, there was no evidence that endometrial scratching has any effects on miscarriage, ectopic pregnancy, or multiple pregnancy. Pain during the procedure was reported in one study, with an average pain score of 6 out of 10.
These meta-analyses indicate a lot of promise for this low-tech, simple procedure for increasing the chances of pregnancy for women attempting to conceive, both with and without the use of other techniques. We want to hear from you! Would you ask for/perform endometrial scratching?