OHSS may be complicated by ovarian torsion, ovarian rupture, venous thromboembolism, acute respiratory distress syndrome, electrolytes imbalance, thrombophlebitis and chronic kidney disease. Symptoms generally resolve in 1 to 2 weeks, but will be more severe and persist longer if pregnancy occurs. This is due to human chorionic gonadotropin (hCG) from the pregnancy acting on the corpus luteum in the ovaries in sustaining the pregnancy before the placenta has fully developed.