Clinical features of severe ovarian hyperstimulation syndrome with hydrothorax

Abstract Research question: Does the presence of hydrothorax suggest that severe ovarian hyperstimulation syndrome (OHSS) is associated with more severe conditions and worse pregnancy outcomes?Design: The clinical data for 868 hospital patients with severe OHSS following IVF-ET at Peking University Third Hospital between January 1, 2016, and July 21, 2021, were retrospectively analysed. The patients were divided into two groups: the ascites alone group (n = 417) and the ascites combined with hydrothorax group (n = 451) to investigate the clinical features and pregnancy outcomes of patients with severe ovarian hyperstimulation syndrome (OHSS) combined with hydrothorax plus ascites.Results The clinical data for 868 hospital patients with severe OHSS following IVF-ET were included. The patients were divided into two groups: the ascites alone group (n = 417) and the ascites combined with hydrothorax group (n = 451). 51.96% of patients with severe OHSS had hydrothorax plus ascites, mainly bilateral and moderate hydrothorax. Most cases with hydrothorax could be monitored and observed, and only 2.66% of the cases required thoracentesis and pleural drainage. Clinically, time to visit due to worsening symptoms was longer; hospital stay was shorter; and OHSS-related laboratory tests such as white blood cells (WBC), haematocrit (HCT), and ovarian diameter were less severe in the ascites combined with hydrothorax group than in the ascites alone group. For live-birth outcomes of IVF-ET, the presence and the volume of hydrothorax were not independent risk factors, while late onset of OHSS (odds ratio [OR]: 0.857 95% confidence interval [CI]: 0.795, 0.925) and a history of foetal reduction (OR: 13.796 95% CI: 1.808, 105.288) were independent protective factors for live birth.Conclusion Patients with severe OHSS combined with hydrothorax plus ascites have less severe clinical manifestations and laboratory tests than those with ascites alone. The presence and the volume of hydrothorax are unrelated to live-birth outcomes following in vitro fertilization and embryo transfer (IVF-ET).