Association between ovarian hyperstimulation syndrome and adverse obstetric and neonatal outcomes in Korea: a nationwide health insurance database study

Purpose: To investigate the association of ovarian hyperstimulation syndrome (OHSS) and adverse maternal and neonatal outcomes. Methods: This retrospective study used combined Korea National Health Insurance (KNHI) claims and National Health Screening Program for Infants and Children data. Women who gave birth through in vitro fertilization using fresh embryo transfer during 2017–2022 were enrolled. Z-scores were calculated. Student’s t-test, analysis of variance, Pearson’s chi-squared (χ²) test, and multivariate logistic regression analyses were performed. Results: The non-OHSS group included 27,337 women, while the OHSS group included 1,570 women (mild to moderate, 1,308; severe, 262). The OHSS group was significantly younger (34.86 ± 3.54 vs. 36.21 ± 3.58 years, p < 0.0001) and had significantly higher rates of primiparity, cesarean section, and polycystic ovary syndrome (88.98% vs. 82.89%, p < 0.0001; 75.8% vs. 65.75%, p < 0.0001; and 29.24% vs. 14.37%, p < 0.0001, respectively). OHSS was associated with a decreased incidence of low birth weight and with an increased incidence of macrosomia (adjusted odds ratio [95% confidence interval], 0.53 [0.38–0.72], p < 0.0001; and 1.83 [1.42–2.35], p < 0.0001). OHSS was associated with an increased incidence of transient tachypnea of the newborn (TTN) and respiratory distress syndrome (RDS) (1.32 [1.02–1.71], p = 0.03; and 1.57 [1.30–1.91], p < 0.0001). Conclusion: OHSS is associated with a decreased incidence of low birth weight and an increased incidence of macrosomia, TTN, and RDS.