The Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) clinical trial was conducted by the National Institute of Child Health and Human Development (NICHD) Cooperative Reproductive Medicine Network; the Collaborative Center for Statistics and Science at Yale University served as the data coordinating center. The trial was conducted at 12 clinical sites throughout the United States.
The trial design has been published previously.22 (link) Briefly, this was a multicenter, randomized clinical trial involving 900 couples with unexplained infertility. Women were between 18 and 40 years of age with regular menses (nine or more cycles per year), had a normal uterine cavity with at least one patent fallopian tube, and had a male partner with a semen specimen of at least 5 million sperm per milliliter. This threshold for the sperm count was used because the protocol incorporated a sperm wash with intrauterine insemination. (World Health Organization [WHO] thresholds for normal sperm counts, which are higher, are based on intercourse rather than insemination.) In addition, a sperm wash was performed to concentrate motile sperm; this approach has been shown to improve pregnancy rates with sperm counts below the WHO threshold.23 (link)Approval for the study was obtained from the institutional review board at each site. Written informed consent was provided by all female and male participants. The first and last authors assume responsibility for the accuracy and completeness of the data reporting and for the fidelity of the report to the study protocol, which is available with the full text of this article atNEJM.org .
The trial design has been published previously.22 (link) Briefly, this was a multicenter, randomized clinical trial involving 900 couples with unexplained infertility. Women were between 18 and 40 years of age with regular menses (nine or more cycles per year), had a normal uterine cavity with at least one patent fallopian tube, and had a male partner with a semen specimen of at least 5 million sperm per milliliter. This threshold for the sperm count was used because the protocol incorporated a sperm wash with intrauterine insemination. (World Health Organization [WHO] thresholds for normal sperm counts, which are higher, are based on intercourse rather than insemination.) In addition, a sperm wash was performed to concentrate motile sperm; this approach has been shown to improve pregnancy rates with sperm counts below the WHO threshold.23 (link)Approval for the study was obtained from the institutional review board at each site. Written informed consent was provided by all female and male participants. The first and last authors assume responsibility for the accuracy and completeness of the data reporting and for the fidelity of the report to the study protocol, which is available with the full text of this article at