Assisted reproductive technology practice patterns and the impact of embryo transfer guidelines in the United States.

Objective: [1] To evaluate trends in number of embryos transferred and resultant high-order multiple (HOM) pregnancy rates by Society for Assisted Reproductive Technology (SART)-member clinics between 1996 and 2003 and [2] to relate these practice patterns and outcomes to clinic compliance with SART-American Society for Reproductive Medicine (ASRM) embryo transfer guidelines.

Design: Retrospective.

Setting: Society for Assisted Reproductive Technology-member fertility centers in the United States.