Multiple births are associated with serious adverse infant and maternal outcomes. The objective of this study was to assess the multiple-birth risk (MBR) associated with IVF and determine whether the risk is impacted by stage of embryo development at transfer.
Epidemic Intelligence Service, Epidemiology Program Office, Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, GA 30341-3724, USA. DKissin@cdc.gov