Ovarian cancer represents 7% of all cancers in pregnant women. Characterizing an ovarian mass during pregnancy is essential to avoid unnecessary treatment and if treatment is required, to plan it accordingly. Ultrasound is the first line modality in these patients and various tools such as IOTA and ADNEX have been validated in non-pregnant patients to accurately categorize ovarian masses according to their malignant potential. A prospective multicentre study, in which Fondazione Policlinico Gemelli is involved, is currently ongoing aiming to validate these tools in pregnant Patients (p-IOTA).

Given the high contrast resolution and the absence of ionizing radiation, Magnetic Resonance Imaging is the preferred second-line modality. It increases the positive predictive value (PPV) of US from 7-50% to 70%, demonstrating a negative predictive value (NV) of 98%. In non-pregnant women, the Ovarian-Adnexal Reporting and Data System-MRI (ORADS-MRI) risk stratification system and the Non-Contrast MRI Score (NCMS) are commonly employed to assess the risk of malignancy in adnexal lesions with accuracies of 92% and 94%, respectively. Recently, both scoring systems have proven effective in retrospectively stratifying benign and malignant adnexal masses in pregnant women.

Inclusion Criteria:

• Pregnant patients > 18 years old
• Ability to understand and sign informed consent
• Patient with adnexal mass detected during pregnancy with either multilocular morphology or solid component at ultrasound examination
• Availability of MR imaging (1.5T and 3.0T MR scanner)
• Availability of histopathological reports obtained during pregnancy or within 3 months from delivery or at least one US follow-up examination 6-12 months after MRI examination

Exclusion Criteria:

• Patients lacking or with low quality MRI

Patients with US-indeterminate adnexal masses detected during pregnancy