Received April 24, 2022
Accepted October 28, 2022

Ovarian hyperstimulation syndrome (OHSS) is characterized by increased vascular permeability, hemoconcentration and fluid leakage to the third space.The vast majority of OHSS cases occur following ovarian stimulation for IVF. This potentially lethal iatrogenic condition is one of the most serious complications of assisted reproductive technologies.We report one cases of severe early OHSS after GnRH agonist trigger in a GnRH antagonist protocol and freeze-all approach without the administration of any hCG for luteal-phase support in a 34 year old case of pco with 7 years primary infertility. 6 after oocyte retrieval the patient was seen at the emergency unit of the hospital with abdominal distension, pain, anuria, dyspnea, and OHSS symptoms. A diagnosis of OHSS with severe ascitis was made. She was admitted to Intensive care unit(ICU). She was managed with oxygen by mask, intravenous fluids, anticoagulant and albumen and two time vaginal ascites puncture was performed, resulting in the removal of 7800 mL clear fluid in Intensive Care Unit with fully recovery.The case study presents her clinical manifestations, investigation, progress, management, outcome and preventive measures.The patient was managed with no complications. Clinicians have to be aware that even the sequential approach to ovarian stimulation with a freeze-all attitude and GNRH analog triggering does not completely eliminate OHSS in all patients.