Context To successfully compete for future patients, fertility specialists strive to achieve high pregnancy rates. If the specialist transfers multiple embryos during an in vitro fertilization (IVF) procedure to obtain high pregnancy rates, the percentage of high order multiples (HOM) may inadvertently rise. ~-- Objective To measure the effect of competition among fertility centers on outcomes in in vitro fertilization. Design and Setting Retrospective cohort of 408 fertility clinics registered with the Society for Assisted Reproduction as providing IVF services in 2000. Competition is defined as number of clinics in a statistical area. Demand for services is based on the population of reproductive aged women. Subjects 381 fertility clinics reporting clinical outcomes Main outcome measures: The clinic high order multiple gestation rate (percentage of pregnancies that were high order multiples) and age adjusted pregnancy rate Results The number of clinics in an area of competition ranged from 1-22. HOM rate per clinic ranged from 0% to 50%. As demand increased, competition increased. As competition increased the number of high order multiples per clinic decreased. In areas of low competition (1-2 clinics) the clinic rate was 8.46%, in areas of intermediate competition (3-7 clinics) 8.39%, and in areas of high competition (8-22 clinics) 8.24%. In areas with intermediate demand, high levels of competition resulted in fewer high order multiples than intermediate competition (RR 0.56, 95% confidence interval 0.36,0.89) or low levels of competition (RR 0.57, 95% confidence interval 0.35, 0.94). Age adjusted pregnancy rates did not differ by level of competition. Conclusions Based on this data, the risk of high order multiple gestation decreases with increasing competition between clinics; however, pregnancy rates are unaffected.Master of Public Healt
