Cesarean scar niche: An evolving concern in clinical practice

To review systematically the medical literature reporting on the prevalence of a niche at the site of a Cesarean section (CS) scar using various diagnostic methods, on potential risk factors for the development of a niche and on niche-related gynecological symptoms in non-pregnant women. The PubMed and EMBASE databases were searched. All types of clinical study reporting on the prevalence, risk factors and/or symptoms of a niche in non-pregnant women with a history of CS were included, apart from case reports and case series. Twenty-one papers were selected for inclusion in the review. A wide range in the prevalence of a niche was found. Using contrast-enhanced sonohysterography in a random population of women with a history of CS, the prevalence was found to vary between 56% and 84%. Nine studies reported on risk factors and each study evaluated different factors, which made it difficult to compare studies. Risk factors could be classified into four categories: those related to closure technique, to development of the lower uterine segment or location of the incision or to wound healing, and miscellaneous factors. Probable risk factors are single-layer myometrium closure, multiple CSs and uterine retroflexion. Six out of eight studies that evaluated niche-related symptoms described an association between the presence of a niche and postmenstrual spotting. The reported prevalence of a niche in non-pregnant women varies depending on the method of detection, the criteria used to define a niche and the study population. Potential risk factors can be categorized into four main categories, which may be useful for future research and meta-analyses. The predominant symptom associated with a niche is postmenstrual spotting. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.

To clarify the appropriate way to diagnose and treat an ectopic pregnancy in the uterine scar of a prior cesarean delivery. Articles written in English that were published from January 1966 to August 2005 and quoted in the computerized database MEDLINE/PubMed retrieved by using the words "cesarean section," "cesarean delivery," "cesarean section scar pregnancy," and "ectopic pregnancy." Additional articles were obtained from reference lists of pertinent case reports and reviews. Fifty-nine articles that met the inclusion criteria provided data on the clinical presentation, diagnosis, and treatment modalities of 112 cases of cesarean delivery scar pregnancies. Review of the 112 cases revealed a considerable increase in the incidence of this condition over the last decade, with a current range of 1:1,800 to 1:2,216 normal pregnancies. More than half (52%) of the reported cases had only one prior cesarean delivery. The mean gestational age was 7.5 +/- 2.5 weeks, and the most frequent symptom was painless vaginal bleeding. Endovaginal ultrasonography was the diagnostic method in most cases, with a sensitivity of 84.6% (95% confidence interval 0.763-0.905). Expectant management of 6 patients resulted in uterine rupture that required hysterectomy in 3 patients. Dilation and curettage was associated with severe maternal morbidity. Wedge resection and repair of the implantation site via laparotomy or laparoscopy were successful in 11 of 12 patients. Simultaneous administration of systemic and intragestational methotrexate to 5 women, all with beta-hCG exceeding 10,000 milli-International Units/mL required no further treatment. Surgical treatment or combined systemic and intragestational methotrexate were both successful in the management of cesarean delivery scar pregnancy. Because subsequent pregnancies may be complicated by uterine rupture, the uterine scar should be evaluated before, as well as during, these pregnancies.