Introduction: The surgical procedure known as one-step conservative surgery for placenta accreta spectrum involves the excision of the placenta and its attachment site on the myometrium. We aimed to conduct a non-randomized comparative study between conservative surgical treatment of placenta accreta spectrum and classical caesarean hysterectomy, under the name of the "CMNT PAS" study. To determine the sample size and the expected difference between the two groups, we conduct this pilot study.   Study design: It was a monocentric prospective observational study from January 4, 2020, to August 17, 2022. Patients were allocated into two groups: Group Conservative Surgery (CSG) in which the method detailed in prior research by Palacios-Jaraquemada was slightly modified by our team, control group (CG) when the caesarean hysterectomy was performed.   Results: Our main goal is to determine the sample size for our principal study and provide adequate data for any other team wishing to study the conservative surgical treatment of placenta accreta spectrum. So, the sample size for a power of 90% and an alpha risk of 5%, the size of each group must be 22 patients. Regarding primary outcomes: estimated blood loss volume was lower in CG compared to CSG but not statistically significant.   Conclusion:   Our pilot study found that the caesarean hysterectomy is similar to conservative surgical treatment for placenta accreta in estimated blood loss. However, the latter helps preserve uterus and possibly fertility.

The authors have declared no competing interest.

ClinicalTrials.gov (ID: NCT06253832)

The author(s) received no specific funding for this work.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics Committee of the Maternity and Neonatology Center of Tunis, Tunis, Tunisia (approval no. 03102020)

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All relevant data are within the manuscript and its Supporting Information files.