Coasting: What is the Cost?

The objective of this article is to review the current literature on the value of coasting for the prevention of ovarian hyperstimulation syndrome (OHSS). Coasting is a common procedure that is performed in ovarian stimulation cycles at risk of OHSS. Coasting is done by stopping FSH injections and monitoring E2 daily until it drops below 3000 pg/mL then hCG is given. Depriving granulosa cells of the FSH stimulus results in their apoptosis, thus reducing levels of E2 and vascular endothelial growth factor (VEGF linked to the pathogenesis of OHSS). Meanwhile, the small follicles that are dependent on FSH will undergo atresia, while large follicles will not be affected. Coasting is effective in reducing the OHSS rate, but complete prevention is not possible. Prolonged coasting is associated with a significantly lower pregnancy rate.