Prevention and Management of Ovarian Hyperstimulation Syndrome (OHSS)

Ovarian hyperstimulation syndrome (OHSS) is an uncommon yet serious complication associated with controlled ovarian stimulation during assisted reproductive technology (ART). Historically, moderate-to-severe OHSS has been reported to occur in approximately 1%–5% of in vitro fertilization (IVF) cycles (1-5). However, the true incidence is difficult to delineate due to the absence of a strict, consensus definition. The traditional description of the syndrome generally includes a spectrum of symptoms, such as abdominal distention and discomfort, dyspnea, and findings like ovarian enlargement, ascites, hemoconcentration, hypercoagulability, and electrolyte imbalances (6-9).

OHSS is staged as mild, moderate, severe, or critical, based on the severity of symptoms and laboratory findings (10). Additionally, it is classified by the timing of onset as early or late (11). Table 5

Classification:

• Early-onset OHSS: Occurs after controlled ovarian hyperstimulation and an ovulatory dose of hCG. Symptoms typically begin 4–7 days post-hCG trigger and usually resolve with menses (12).
• Late-onset OHSS: Usually begins at least 9 days post-hCG trigger, in response to rising hCG levels of pregnancy. This type is more severe and significantly prolongs the course of OHSS (13).

Ovarian torsion and ovarian haemorrhage may be considered serious complications of OHSS. Clinicians should be aware of these complications in history taking and examination of cases with OHSS. (31)

Severe OHSS can lead to life-threatening complications, including pleural effusion, acute renal insufficiency, and venous thromboembolism (14).

OHSS association mortality is recorded in the literature as 1:500,000. However, this may be an underestimation of the true related mortality rate as some cases are handled by other specialists. (31)