Ovarian Hyperstimulation Syndrome (OHSS) is a spectrum of clinical features typically resulting from assisted conception techniques. With 2.35% of all live births in the UK resulting from in-vitro fertilisation (IVF), OHSS is on the rise. Moreover, there has been an increase in the presentation of its complications to GP surgeries and unscheduled acute care services nationwide. This review will discuss signs and symptoms of the increasingly common and potentially fatal complications of OHSS, namely pleural effusion, ascites and thromboembolic events. With such propensity toward critical, life-threatening events it is not only prudent to recognise the population at risk, but also to be aware of the signs, symptoms and complications to expedite treatment and ensure optimum outcome.