['To determine if elevated body mass index in young women with normal ovarian reserve was associated with poorer ovarian response, difficulty at embryo transfer, and lower clinical pregnancy rates.', 'Retrospective study of 417 first, fresh in vitro fertilization cycles performed between October 2004 and December 2006. All women were under the age of 35 and had normal cycle day 3 follicle stimulating hormone and estradiol levels. Subjects were divided into groups by BMI: <18.5, 18.5-24.9, 25-29.9, > or = 30.', 'Cancellation rates, peak estradiol levels, and mean number of oocytes retrieved were similar in all groups. There was a trend toward increasing difficulty in visualizing the air bubble at time of embryo transfer and lower implantation rates at higher body mass indices. Clinical and ongoing pregnancy rates were similar among groups.'] Does elevated body mass index ( BMI ) adversely affect in vitro fertilization outcome in young women?