Assessment of multiple intrauterine gestations from ovarian stimulation (AMIGOS) trial: baseline characteristics

Objective To identify baseline characteristics of women with unexplained infertilityto determine whether treatment with an aromatase inhibitorwill result in a lower rate of multiple gestations than current standard ovulation inductionmedications. Design Randomized, prospective clinical trial. Setting Multicenter university-based clinical practices. Patient(s) A total of 900 couples with unexplained infertility. Intervention(s) Collection of baseline demographics, blood samples, and ultrasonographic assessments. Main Outcome Measure(s) Demographic, laboratory, imaging, and survey characteristics. Result(s) Demographic characteristics of women receiving clomiphene citrate (CC), letrozole, or gonadotropins for ovarian stimulation were very consistent. Their mean age was 32.2 ± 4.4 years and infertilityduration was 34.7 ± 25.7 months, with 59% primary infertility. More than one-third of the women were current or past smokers. The mean body mass index (BMI) was 27 and mean antimullerian hormone level was 2.6; only 11 women (1.3%) had antral folliclecounts of Conclusion(s) The cause of infertilityin the couples recruited to this treatment trial is elusive, as the women were regularly ovulating and had evidence of good ovarian reserveboth by basal FSH, antimullerian hormone levels, and antral folliclecounts; the male partners had normal semen parameters. The three treatment groups have common baseline characteristics, thereby providing comparable patient populations for testing the hypothesis that use of letrozolefor ovarian stimulation can reduce the rates of multiples from that observed with gonadotropin and CC treatment. Clinical Trial RegistrationNumber NCT 01044862.