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Definition and sonographic reporting system for Cesarean scar pregnancy in early pregnancy: modified Delphi method
Definition and sonographic reporting system for Cesarean scar pregnancy in early pregnancy: modified Delphi method
REVIEWED BY | Jennifer Alphonse PhD ASA SIG: Gynaecology
REFERENCE | Authors: IPM Jordans, C Verberkt, RA de Leeuw, CM Bilardo, T van den Bosch, T Bourne, HAM Brölmann, M Dueholm, WJK Hehenkamp, N Jastrow, D Jurkovic, A Kaelin Agten, R Mashiach, O Naji, E Pajkrt, D Timmerman, O Vikhareva, LF van der Voet, JAF Huirne Journal: Ultrasound in Obstetrics and Gynecology Open Access: Yes
WHY THE STUDY WAS PERFORMED
Due to the ever-increasing number of deliveries by Caesarean section (CS), subsequentpregnancies may be at higher risk of caesarean scar pregnancy (CSP), placenta accretespectrum (PAS) and other pathophysiological processes with high morbidity and mortality.These guidelines were developed to provide a standardised approach for the evaluation andreporting in the first trimester of CSP for both expert and general sonographic providers as nouniversally accepted reporting system existed.
HOW THE STUDY WAS PERFORMED
A modified Delphi procedure was conducted with repeated rounds of questionnaires derived from the available literature and presented to experts, analysed and re-presented in multiple rounds until a consensus was achieved. PubMed and EMBASE databases were searched with strict criteria relating to the research question and if the literature defined or evaluated a CSP by ultrasound. The experts included obstetric and gynaecological clinicians with advanced ultrasound experience. Twenty-eight experts were invited; however, only 16 participated in the Delphi study. The data collection ran from July 2018 to August 2020 and included four rounds of online questions and one face-to-face meeting with 62.5% participation. Responses were anonymised and consensus was achieved for all 58 items.
WHAT THE STUDY FOUND
• The optimal gestational age (GA) for the assessment of CSP, including localisation of the gestational sac (GS) and placenta is 6–7 weeks; however, the recommendations apply to gestations up to 12 weeks.
• CSP includes all pregnancies (GS/placenta) with implantation in close contact or within the niche, while a pregnancy near the CS/niche but not in contact is classified as low implanted pregnancy. Further description of the CSP depended on the GS crossing two imaginary lines, agreed upon by the panel as the uterine cavity line and/or serosal line. Multiple images and representative schematic drawings are provided to assist in the definition and description.
• In the case of CSP, measurement (2D) of the residual myometrial thickness (RMT) and adjacent myometrial thickness (AMT) in sagittal place were determined to be useful; however, measurement of the niche was deemed irrelevant.
• Colour Doppler imaging (CDI) assisted in the evaluation of trophoblastic invasion and CSP identification as well as in the presence of CSP, CDI could assist in differentiation between low implantation pregnancy or miscarriage. CDI is essential in identifying retained placental tissue with the ability to differentiate from other uterine anomalies and haemorrhage.
• A flow chart is provided to guide sonographers in differentiating between three important clinical presentations: CSP, cervical pregnancy and miscarriage.
Definition and sonographic reporting system for Cesarean scar pregnancy in early pregnancy: modified Delphi method continued
RELEVANCE TO CLINICAL PRACTICE
There are clear criteria provided for both basic and advanced evaluation of CSP with tables and figures providing visual support, enhancing the readability and assisting in clinical application.
The schematic diagrams, accompanied by ultrasound images, are of enormous benefit.
When in any doubt of the position of the GS/placenta in relation to the CS, referral to an expert clinic is recommended over MRI, as MRI was deemed to be of no value in the assessment of CSP.
