['The objective of the present investigation was to determine implantation and pregnancy rates in patients undergoing ICSI and treated with beta2-adrenergic agonists, considering the uterine-relaxing action of these agents.', 'A total of 225 women undergoing ICSI at the Center for Human Reproduction, "Sinhá Junqueira" Maternity Foundation, entered the study. Patient participation in each group was random, by drawing lots, using a randomization table previously elaborated for the study (2:2:1). The group I (90 women) received 10 mg of terbutaline daily for 15 days starting on the day of oocyte retrieval; group II (90 women) received 20 mg of ritodrine daily during the same period of time as group I; group III (45 patients) received no treatment and was used as control. The evaluation was interrupted in 3 patients of group I and in 30 patients of group II because of a high incidence of side effects.', 'Pregnancy, implantation, and miscarriage rates were not significantly different (p > 0.05) between the three groups: 29.88%, 13.25%, and 26.9% for group I; 33.33%, 17.5%, and 10.0% for group II; 28.88%, 15.07%, and 15.38% for group III, respectively.'] Does administration of beta2-adrenergic agonists during the peri-implantation period improve implantation or pregnancy rates in intracytoplasmic sperm injection ( ICSI ) cycles?