Definition and sonographic reporting system for Cesarean scar pregnancy in early gestation: modified Delphi method

Abstract

Objective To develop a standardized sonographic evaluation and reporting system for Cesarean scar pregnancy (CSP) in the first trimester, for use by both general gynecology and expert clinics. Methods A modified Delphi procedure was carried out, in which 28 international experts in obstetric and gynecological ultrasonography were invited to participate. Extensive experience in the use of ultrasound to evaluate Cesarean section (CS) scars in early pregnancy and/or publications concerning CSP or niche evaluation was required to participate. Relevant items for the detection and evaluation of CSP were determined based on the results of a literature search. Consensus was predefined as a level of agreement of at least 70% for each item, and a minimum of three Delphi rounds were planned (two online questionnaires and one group meeting). Results Sixteen experts participated in the Delphi study and four Delphi rounds were performed. In total, 58 items were determined to be relevant. We differentiated between basic measurements to be performed in general practice and advanced measurements for expert centers or for research purposes. The panel also formulated advice on indications for referral to an expert clinic. Consensus was reached for all 58 items on the definition, terminology, relevant items for evaluation and reporting of CSP. It was recommended that the first CS scar evaluation to determine the location of the pregnancy should be performed at 6–7 weeks' gestation using transvaginal ultrasound. The use of magnetic resonance imaging was not considered to add value in the diagnosis of CSP. A CSP was defined as a pregnancy with implantation in, or in close contact with, the niche. The experts agreed that a CSP can occur only when a niche is present and not in relation to a healed CS scar. Relevant sonographic items to record included gestational sac (GS) size, vascularity, location in relation to the uterine vessels, thickness of the residual myometrium and location of the pregnancy in relation to the uterine cavity and serosa. According to its location, a CSP can be classified as: (1) CSP in which the largest part of the GS protrudes towards the uterine cavity; (2) CSP in which the largest part of the GS is embedded in the myometrium but does not cross the serosal contour; and (3) CSP in which the GS is partially located beyond the outer contour of the cervix or uterus. The type of CSP may change with advancing gestation. Future studies are needed to validate this reporting system and the value of the different CSP types. Conclusion Consensus was achieved among experts regarding the sonographic evaluation and reporting of CSP in the first trimester. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Conservative Management of Cesarean Scar Pregnancy: A Case Report and Literature Review

“…The ultrasound diagnostic criteria for CSP were defined as follows [ 4 , 10 , 11 ]: Empty uterus with clearly visualized endometrium Empty cervical canal Gestational sac implanted in the lower anterior uterine segment at the presumed site of the cesarean section incision scar Thin or absent myometrium between the gestational sac and the bladder (the majority of cases have a myometrium thickness<5 mm). “Sliding organ sign” Doppler Flow at the previous cesarean scar …”

Caesarean Scar Pregnancy: A Case Report

“…The diagnostic criteria of CPS include I) an empty uterine cavity and endocervical canal, II) a gestational sac or trophoblast located in the niche of previous caesarean scar site, III) a gestational sac with or without foetal pole in the presence or absence of cardiac activity, IV) a thin or absent layer of myometrium between the gestational sac and the urinary bladder and V) an intense trophoblastic or placental perfusion on colour Doppler imaging [1,2,6,11]. According to gestational sac relation with uterine cavity and serosa CSP is classified into three types: I) CSP implanted into the niche with largest part of gestational sac extending into uterine cavity; II) CSP located within myometrium not crossing serosal and uterine cavity lines; III) CSP protruded towards urinary bladder, while crossing serosal line [3]. Magnetic resonance imaging is known to be used as an adjunct to ultrasonography in CSP cases [6,12].…”

“…Magnetic resonance imaging is known to be used as an adjunct to ultrasonography in CSP cases [6,12]. However, there is no evidence to suggest that magnetic resonance imaging could have any additional value in early CSP diagnosis and should not be used as routine diagnostic modality in CSP cases [3,6].…”

“…Caesarean scar pregnancy (CSP) is defined by implantation of the trophoblast into the niche of previous caesarean scar site [1,2,3]. The prevalence of this condition directly depends on caesarean section rate, which has significantly increased during the last decades and now reaches 21.1 percent worldwide [4].…”

Cesarean scar pregnancy IS an ectopic pregnancy

“…The abundance of robust evidence showing that scar implantation is a major complication of pregnancy, caused by growth of the pregnancy outside the uterine cavity, prompted the Royal College of Obstetricians and Gynaecologists, in its guideline on ectopic pregnancy (which was written by six and peer-reviewed by 38 international experts), to classify Cesarean scar pregnancy as a type of ectopic pregnancy 5 . A recent Delphi consensus endorsed by 19 international experts also supported classifying a scar pregnancy as ectopic 6 .…”