Comparison between Transabdominal and Transvaginal Sonographic Assessment of Lower Uterine Segment at Term in Women with Previous Cesarean Delivery

Abstract

Caesarean section (CS) rates have increased over recent years and according to data from 150 countries, current rates range from 6% to 27.2%. Accordingly, the number ofCS complications has increased. Among early complications postpartum haemorrhage, obstetric hysterectomy due to uterine rupture or atony, urological complications, thromboembolic complications and amniotic fluid embolism may occur. Late complications after CS include abdominal pain caused by adhesions, caesarean scar, endometriosis, ectopic pregnancy, caesarean scar defect (CSD),abnormal placenta implantation and even mortality. First described in 1995 following examinations of myometrium samples after hysterectomy in patients who had undergone CS, a cesarean scar defect (CSD) may form at the site of hysterotomy on the anterior wall of the uterine isthmus. Improper healing of the caesarean incision leads to thinning of the anterior uterine wall, which creates an indentation and fluid-filled pouch at the CS site. The complication is also known as uterine scar defect, caesarean scar syndrome, diverticulum, sacculation, isthmocele, scar pouch or niche. The type of surgical technique used for uterine closure has been proposed as an important factor in the formation of CSD. Other factors such as prolonged labour, cervical dilatation >5cm before CS, oxytocin, retroverted uterus, low incision of the uterus have also been suggested as being responsible for the abnormal healing of the caesarean scar. The CSD may be asymptomatic or manifest with clinical symptoms including metrorrhagia (64%), dysmenorrhea (53%), chronic pelvic pain (40%), infertility and dyspareunia (18%). CSD may expand and lead to scar dehiscence or uterine rupture in a subsequent pregnancy as well as result in scar pregnancies and abnormal placentae. Ultrasound examination with the possible use of saline infused sonohysterography has been used in the diagnosis of CSD. One classification system for CSD was based on the shape of the niche detected from ultrasound findings.