Background: Transient bone marrow oedema (BMO) of the hip presents with pain, is diagnosed by magnetic resonance imaging (MRI), and usually resolves within 6 months. Risk factors include pregnancy. Avascular necrosis of bone and an association with BMO are among the less common presentations of antiphospholipid syndrome (APS). Aim of the work: To present a young Croatian female APS patient who developed transient BMO during pregnancy which spontaneously resolved postpartum. Case report: After developing left leg deep vein thrombosis and positive lupus anticoagulant at 22 years old, the patient was diagnosed with primary APS. Antinuclear antibody was borderline, but classification criteria for SLE were not fulfilled. She had an early missed abortion during her first pregnancy while receiving low-weight molecular heparin (LWMH) (enoxaparin 40 mg), and her second pregnancy was to term with LWMH, aspirin, and hydroxychloroquine 200 mg daily. During the third trimester of this pregnancy, she developed excruciating bilateral hip pain to the point she could barely walk. Based on an MRI scan, the patient was diagnosed with bilateral BMO of the femoral head. The condition improved and resolved within four months with conservative treatment postpartum, as confirmed by followup MRI. Conclusion: Considering that pregnancy and APS are risk factors for BMO, both played a role in the development of BMO and the severity of presentation. This case report presents a differential diagnosis of hip pain in pregnant patients, especially with APS. Although APS is commonly associated with AVN, it may also be associated with transient BMO.