Pregnancy is a well-recognised risk factor in precipitating obsessive-compulsive disorder. We present and discuss a case with the onset of obsessive-compulsive disorder in the fourth month of gestation, which fully recovered two weeks after delivery. The phenomenology of the observed disorder was similar to earlier reports of obsessive-compulsive disorder in pregnancy, i.e. the obsessions and compulsions were predominantly related to the concern of contaminating the foetus resulting in washing compulsions. Despite the initial success with anti-obsessional drugs, the patient stopped the medication in the last month of gestation. Nevertheless, she fully recovered two weeks after the delivery without any psychiatric intervention. There were no obsessive-compulsive symptoms at one-year follow up. The possible mechanisms involved in the aetiology of this case, and future research directions in understanding the role of pregnancy in OCD are discussed.