Objective: To describe a suggested version of the Clavien-Dindo morbidity classification specific to obstetrics and employ it to build a cumulative morbidity score which fully reflects the ‘patient experience’. To demonstrate the utility of this novel system in a cohort of women with Placenta Accreta Spectrum (PAS).   Design: Delphi consensus and retrospective application of the resulting scores to morbidity from PAS surgery.   Setting: UK Tertiary referral centre for PAS.   Population: Women who had caesarean hysterectomy for PAS.   Methods: The Clavien-Dindo classification was modified to reflect obstetric procedures and a quantitative morbidity measure, the Soleymani and Collins Obstetric Morbidity Score (SaCOMS), was developed based on this. Both were then validated using a Delphi consensus of experts in PAS and retrospectively applied to a cohort of 54 women with PAS.   Main Outcome measures: Delphi consensus of >80%, binary outcome of adverse event or not and quantitative values from the SaCOMS.   Results: Clinicians with expertise in PAS believe that the Modified Obstetric Clavien-Dindo classification system and the novel SaCOMS tool can improve assessment of maternal morbidity, and better reflect the ‘patient experience’. Application to the PAS cohort demonstrates that surgery by gynae-oncological surgeons may be associated with decreased incidence and cumulative morbidity outcomes for women with PAS, especially those with the most severe presentation.     Conclusions: This study presents a clinically useful obstetric-specific classification system for surgical morbidity. SaCOMS also provides a quantitative reflection of the full patient- journey experienced as a result of surgical complications enabling a more patient-centred representation of morbidity.