What is recurrent implantation failure and how do we manage it?

This paper reviewed what recurrent implantation failure is and how it can be treated.

Implantation is the process where the embryo attaches to the outer layer of the uterus and moves into the deeper layer of the uterus. Recurrent implantation failure occurs when implantation repeatedly fails.  

The quality of the eggs and sperm may be a reason why embryos do not implant. An older age is associated with reduced egg quality. Aggressive ovarian stimulation (process to stimulate release of eggs) may lead to poor quality eggs.  Uterus birth defects and hydrosalpinges (widened and blocked fallopian tube) decrease implantation rate. Fibroids (abnormal growths of the uterus) could lead to a decreased implantation rate . Polyps (growths from the inner wall of the uterus) and adenomyosis (growth of uterus into muscle)  also decrease implantation rate.

Management.

Couples should stop smoking, maintain a healthy weight and reduce alcohol consumption. The response to gonadotropin stimulation (treatment for infertility) should be reviewed.

Medical treatments or other techniques could improve the quality of sperm. Ultrasound guidance (a procedure), aids the transfer of embryos and could increase pregnancy rates.

Studies have suggested that hysteroscopy (procedure to look at uterus), should be performed. Submucous fibroids (growths from the inner side of the uterus) if present, should be removed. However, it is not clear whether or not intramural fibroids (growths from within the uterus wall) should be removed. Uterine septae (birth defect) and intrauterine adhesions (scar tissue on uterine cavity) should also be removed. Studies show that removing hydrosalpinges improves implantation in women.

Studies also suggest that an endometrial scratch (lining of the uterus is gentrly 'scratched' – causes a 'repair reaction' in the uterus which may benefit the uterus lining) could be beneficial. Studies have suggested that sildenafil citrate (Viagra) could benefit women with a thin endometrium. Studies suggest that aspirin should not be administered. 

The authors concluded that recurrent implantation failure should be defined as no pregnancy after transferring at least 4 good quality embryos in at least three cycles in a woman under 40 years old, and suggested a number of ways of managing this.