Case reports of delusion of pregnancy have emanated from all over the world, yet the rarity of this phenomenology has precluded systematic large scale descriptive or cohort studies. This systematic review was conducted to assess the demographic characteristics, clinical profile, treatment outcome and aetiological factors from the published case reports of delusion of pregnancy. Electronic databases including PubMed, PsychInfo and Google Scholar were used to identify case reports relating to delusion of pregnancy published in peer-reviewed English language journals. All such cases were systematically evaluated by investigators, and information was extracted using a structured proforma. A total 40 articles were reviewed which included 84 cases. Demographic characteristics revealed that about half of the patients were aged 20-40 years. The most common diagnoses were schizophrenia (35.7%), bipolar disorders (16.7%) and depression (9.5%). Single foetus was reported by 79.8% of the patients, and 45.2% perceived foetal movements. Good treatment response was noted in 64.3 % of the cases. The prominent aetiological factors that were implicated included psychosocial factors, coenaesthopathological processes, socio-cultural factors and hyperprolactinaemia. Delusion of pregnancy is a heterogeneous symptom which emerges during the course of various neuropsychiatric disorders. A range of aetiopathological mechanisms have been implicated in the causation of this disorder.