SYDNEY, AUSTRALIA – A single round of endometrial scratching during oral contraceptive pill pretreatment can significantly increase the clinical pregnancy rate in women undergoing assisted reproductive treatment, a randomized controlled trial showed.
The study, presented at the International Society of Ultrasound in Obstetrics and Gynecology world congress, showed an 83% increase in the chance of a live birth (41.8% vs. 22.8%) and a 70% increase in the chance of clinical pregnancy (49.4% vs. 29.1%) in women who had endometrial scratching, compared with women who underwent a sham procedure.
Endometrial scratching did not have any significant effect on the rate of miscarriage (15.4% vs. 21.7%,) and multiple pregnancy (22.5% vs. 25.0%), according to data that was also published online in the Sept. 2 issue of Ultrasound in Obstetrics and Gynecology (2013;42:375-82 [doi: 10.1002/uog.12539]).
The 77 women randomized to endometrial scratching reported significantly higher pain scores during the procedure than the 79 women given the sham therapy. No major fetal malformations were reported by study participants.
The procedure, which was performed 7-14 days before the planned start of controlled ovarian stimulation, involved introducing the Pipelle suction curette through the cervix and up to the uterine fundus, then applying suction and moving the device around with the aim of covering the entire endometrium.
The sham procedure consisted of drying the cervix with gauze for 30 seconds.
A link between endometrial scratching and the increased chance of pregnancy was first identified in 2003; however, coauthor Dr. Wellington Martins said this was the first study to examine its use during oral contraceptive pill (OCP) pretreatment.
"No previous study has studied endometrial injury performed during OCP pretreatment, only in natural cycles, but in our center we use OCP pre-treatment for all women undergoing assisted reproductive therapy," said Dr. Martins of the University of São Paolo (Brazil).
Dr. Martins said the study also included all women undergoing assisted reproductive therapy, not just those with repeated implantation failure, although the majority of participants had had at least two previous, unsuccessful embryo transfers.
The effect of endometrial scratching is thought to be possibly mediated by inflammation, with the injury causing increased secretion of cytokines, interleukins, growth factors, and dendritic cells, which could aid embryo implantation.
Another mechanism may be the improved synchronization between the endometrium and implanted embryo.
"In assisted reproduction, the higher estrogen levels make the endometrium a little advanced, but it is possible that the injury or the healing process retard the maturity and development of the endometrium and promote a better synchronization," Dr. Martins said in an interview.
The study was terminated before full enrollment was achieved because of the significant benefit noted in an interim analysis, and while research is continuing, Dr. Martins said the treatment was already being offered to women attending their clinic.
No financial conflicts were reported.
This story was updated on October 29, 2013.