From the Research
Ovarian hyperstimulation syndrome (OHSS) typically develops 3-7 days after egg retrieval in IVF procedures. Early-onset OHSS can appear within 24-48 hours following administration of hCG (human chorionic gonadotropin) trigger before retrieval, while late-onset OHSS may develop 9-12 days after retrieval, especially if pregnancy occurs 1. Symptoms include abdominal bloating, nausea, vomiting, weight gain, and in severe cases, shortness of breath and decreased urination. Management includes rest, hydration (2-3 liters of fluid daily with electrolyte replacement), pain relief with acetaminophen, and monitoring weight and abdominal circumference. Severe cases require hospitalization. OHSS occurs because fertility medications stimulate multiple follicle development, causing the ovaries to become enlarged and leaky, releasing fluid into the abdominal cavity. The risk increases with higher estrogen levels, large numbers of follicles, and when pregnancy occurs, as naturally produced hCG further stimulates the ovaries.
Pathophysiology and Prevention
The pathophysiology of OHSS involves the release of vasoactive substances, such as interleukins, tumor necrosis factor-α, endothelin-1, and vascular endothelial growth factor (VEGF), which increase vascular permeability 2. Prevention strategies include coasting, administration of albumin, renin-angiotensin system blockage, dopamine agonist administration, non-steroidal anti-inflammatory administration, GnRH antagonist protocols, reducing hCG dosage, replacement of hCG, and in vitro maturation of oocytes (IVM) 3. However, the current evidence points to the replacement of hCG by GnRH agonists in antagonist cycles and the performance of IVM procedures as the safest approaches.
Risk Factors and Management
The risk of OHSS is increased in patients with polycystic ovary syndrome, high estrogen levels, and large numbers of follicles 4. Management of OHSS includes hospitalization for severe cases, and the use of prophylactic albumin administration to increase plasma oncotic pressure and bind mediators of ovarian origin 2. Cabergoline may also be used to inhibit VEGF receptor 2 phosphorylation levels and associated vascular permeability without affecting luteal angiogenesis, reducing the risk of early-onset OHSS 2.
Recent Findings
Recent studies have reported cases of severe OHSS despite the use of GnRH agonist triggering and freeze-all protocol, highlighting the need for continued vigilance and monitoring in high-risk patients 5, 1. These findings suggest that the risk of OHSS is not entirely eliminated with the use of GnRH agonist triggering and freeze-all protocol, and that other factors, such as polycystic ovary syndrome, may contribute to the development of OHSS.