Ultrasound Based Study For Niche Development In The Uterine Cesarean Section Scar

Cesarean delivery is amongst the most widely recognized operations performed on women and its rate continue expanding. The rates of cesarean section (CS) in the United States in 1996 and 2009 were 20.7% and 32.3% respectively, witnessing an expansion of more than half. In China, 50% of deliveries in 2010 were through CS. In the Netherlands, the cesarean delivery rate jumped from 7.4 to 15.8% between 1990 and 2008, whereas in the United Kingdom, the CS rate increased from 12 to 29% throughout the same time period. In Brazil, the CS rate jumped from 15% in 1970 to even 80% in 2004.

The expanding rate of cesarean deliveries can be credited to many variables including an increase in repeated cesarean sections. There is no discourse that CS is a lifesaving method for a few women, for instance for women with placenta previa or obstructed labor, or for fetuses with either antenatal or intrapartum distress, breech pregnancy or a twin pregnancy. The World Health Organization suggests that the ideal CS rate should be 15%.

Also, this expanding CS rate has fortified an enthusiasm for the potential long-term morbidity of CS scars. By and large, the cesarean incision heals uneventfully. However, some authors depicted a cesarean scar defect on transvaginal sonography (TVS) or saline infusion sonography (SIS) as a wedge shape anechoic structure at the site of the scar or a gap in anterior myometrium of the anterior lower myometrium at the site of previous cesarean section site. This was first described using hysterosalpingography in 1961. The terminology used to describe these scar abnormalities include scar defects, or 'niches' in the uterine scar, cesarean scar defect, uterine diverticulum, uterine isthmocele, pouch or sacculation and differs various publications. The term 'niche', which was introduced in 2001. A niche appears to be frequently present after a CS. Using SIS, niches were identified in the scar in more than half of the women who had had a caesarean delivery. Niches were defined as indentations of the myometrium of at least 2 mm. Large niches occur less frequently, with an incidence varying from 11 to 45% dependent on the definition used (a depth of at least 50 or 80% of the anterior myometrium, or the remaining myometrial thickness ≤2.2 mm when evaluated by TVS and ≤2.5 mm when evaluated by sonohysterography).

It is usually asymptomatic. Be that as it may, some authors have described some symptoms identified with this condition and there are several studies relating abnormal uterine bleeding and niche, especially postmenstrual spotting which appears to be the most common symptom in women with niches due to the collection of menstrual blood in a uterine scar defect causing postmenstrual spotting.

Later prospective cohort studies reported spotting in ∼30% of women with a niche at 6- 12 months after their CS compared with 15% of women without a niche after CS. It is undoubtedly a generally new pathology that needs assessment.

Inclusion criteria

• Cases are delivered by Lower segment cesarean section
• Controls are delivered vaginally
• Singleton fetus
• Living fetus
• Term pregnancy

Exclusion criteria

• Placenta praevia
• Congenital fetal anomalies
• Severe oligohydramnios(MVP <2cm)
• Rupture of membranes more than 18 hours
• Puerperal pyrexia or sepsis
• Bladder injury
• Blood transfusion