Caesarean section (CS) results in the occurrence of the phenomenon 'niche'. A 'niche' describes the presence of a hypoechoic area within the myometrium of the lower uterine segment, reflecting a discontinuation of the myometrium at the site of a previous CS. Using gel or saline instillation sonohysterography, a niche is identified in the scar in more than half of the women who had had a CS, most with the uterus closed in one single layer, without closure of the peritoneum. An incompletely healed scar is a long-term complication of the CS and is associated with more gynaecological symptoms than is commonly acknowledged. Approximately 30% of women with a niche report spotting at 6-12 months after their CS. Other reported symptoms in women with a niche are dysmenorrhoea, chronic pelvic pain and dyspareunia. Given the association between a niche and gynaecological symptoms, obstetric complications and potentially with subfertility, it is important to elucidate the aetiology of niche development after CS in order to develop preventive strategies. Based on current published data and our observations during sonographic, hysteroscopic and laparoscopic evaluations of niches we postulate some hypotheses on niche development. Possible factors that could play a role in niche development include a very low incision through cervical tissue, inadequate suturing technique during closure of the uterine scar, surgical interventions that increase adhesion formation or patient-related factors that impair wound healing or increase inflammation or adhesion formation.

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Why do niches develop in caesarean uterine scars? Hypotheses on the aetiology of niche development

New Insights into the Etiopathology of Placenta Accreta Spectrum.

/pdf/searching-for-placenta-percreta-a-prospective-cohort-and-27cehnqi.pdf

Searching for placenta percreta: a prospective cohort and systematic review of case reports

Development of the utero-placental circulation in cesarean scar pregnancies: a case-control study.

/pdf/development-of-the-utero-placental-circulation-in-cesarean-27c1uc7y.pdf

Development of the utero-placental circulation in cesarean scar pregnancies: a case-control study

AIM To compare smooth muscle cells, type I collagen, and apoptosis of the lower uterine segment of women who had/without a prior cesarean delivery METHODS Alpha smooth muscle actin (α-SMA), type I collagen, and nuclear apoptosis were compared between the groups from lower uterine segment Twenty-eight controls and 82 with one prior cesarean delivery were included The women with a prior cesarean section were classified by time since the surgery: ≤3 years, >3 and ≤5 years, >5 and ≤7 years, >7 and ≤9 years, and >9 years RESULTS Smooth muscle volume density (VD) % was significantly lower in women who had cesarean sections in first three groups than in the controls (all, P<001) Type I collagen VD% was similar among all groups and the controls The number of apoptotic nuclei in the lower uterine segment of the scarred group was greater up to 3 years after surgery and less than in the control at 7-9 years The number of non-apoptotic nuclei in the scarred group was greater than controls up to 7 years after surgery CONCLUSION The lower uterine segment scar becomes stable at 3 years after cesarean delivery, and by 9 years, the scar is mature

Liangzhi Wu

Papers

A preliminary study of uterine scar tissue following cesarean section.