Finally, this case demonstrates the importance of timely and correct diagnosis in PAH. Evidence suggests that treatment of mildly symptomatic patients can be beneficial, and indeed data from the EARLY trial [5] led to regulatory authority approval for the use of bosentan in the treatment of PAH patients in NYHA/WHO FC II and a recommendation for treatment of such patients in recent guidelines [3]. In this case the patient's condition deteriorated between her initial misdiagnosis of post-partum depression and her referral to our specialist centre 3 months later, removing the option for early treatment before her symptoms became marked.