Cesarean Section Scar Niche: The Impact on Assisted Reproductive Technology Outcome

The incidence of Cesarean section (CS) is increasing worldwide, with a corresponding increase in its associated complications. The well-known complications are infection, hemorrhage, and increased risk of obstetric complications in subsequent pregnancies, like morbidly adherent placenta, cs scar pregnancies and uterine rupture.

In addition, some studies emphasize the effect of cesarean sections on reduced fertility. A meta-analysis reported that a Caesarean section reduces the probability of subsequent pregnancy by 10%, compared with a previous vaginal delivery.

The cesarean section niche is defined as an indentation of the uterine myometrium of at least 2 mm at the site of the caesarean scar. The most common symptom of niche is abnormal uterine bleeding. Meanwhile, other symptoms include dysmenorrhea, chronic pelvic pain, dyspareunia, and sub-fertility/infertility.

The detection of a cesarean section niche depends on the operator and the diagnostic method used. This can be 2D, 3D transvaginal sonography, sonohysterography or hysteroscopy.

Regarding ART, the presence of cs niche was reported to reduce the chances of embryo implantation, and increase the rate of spontaneous miscarriages, especially if the implantation is close to it or in the niche.