Coasting, embryo development and outcomes of blastocyst transfer: a case-control study

This study compared the effect on blastocyst development and clinical outcome of coasting in women at increased risk of moderate-severe ovarian hyperstimulation syndrome (OHSS; n = 389) with a control group matched for age and basal FSH that did not undergo coasting (n = 386) in IVF/intracytoplasmic sperm injection (ICSI) cycles. The main outcome measures were rate of blastocyst development and live birth. More cycles progressed to the blastocyst stage in the coasted group (n = 169) compared with the control group (n = 83; 43.4% versus 21.5%; P < 0.001). The biochemical pregnancy, clinical pregnancy and live birth rates were similar (46.5% versus 42.0%; 40.6% versus 37.8%; 31.6% versus 30.1%). The duration of coasting up to 4 days did not affect progression to blastocyst stage. The multivariate model showed that coasting (OR 1.73, P = 0.004) and the number of oocytes retrieved (OR 1.17, P = 0.001) were positively correlated with blastocyst formation. Coasting, a measure to reduce the risk of OHSS, does not impair blastocyst development or clinical outcome. Coasting should remain an effective measure to prevent OHSS. (C) 2014 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.