Objective: Multifetal pregnancy as a result of ovulation induction (OI) and assisted reproductive technologies (ART) correlate with Board certification in reproductive endocrinology and infertility (REI).Design: Retrospective chart analysis of 304 patients referred to Wayne State University (WSU) and Thomas Jefferson University (TJU) for multifetal pregnancy reduction (MFPR) from March 1986 to January 1995 compared to 275 patients referred from January 1 to December 31, 2000 at MCP Hahnemann University.Material And Methods: Chart review for fetal number, pregnancy generation (OI or ART) and physician REI Board certification from the American Board of Specialties Obstetrics and Gynecology. Information was available on 296 of 304 patients studied in the 1986-1995 WSU cohort and 275 patients studied from the MCP Hahnemann 2000 cohort.Results: Analysis of 296 multifetal pregnancies at WSU and TJU for REI Board status showed non-REI Board-certified (NREI) physicians generated 174 pregnancies with quadruplets or more compared to 122 quadruplets or more by REI Board-certified physicians. Board certification did not impact quadruplet or more rates for OI or ART (p < 0.368). Of 275 patients with triplets or more at MCP Hahnemann, 156 (56.7%) were from ARTs versus 41.2% from 1986-1995 (chi(2) = 13.1, p < 0.001). Quintuplets or more decreased from 18.5 to 9.7% (chi(2) = 8.3, p = 0.004), and for REIs from 22.1 to 9.6% (chi(2) = 4.7, p < 0.01), while 14.4% of cases coming from non-REIs had quintuplets versus 9.6% from REIs (p = NS).Conclusions: Cases of MFPR from ARTs have risen, while percentage of cases with quintuplets have fallen in half. We found no difference in quintuplets between REIs and non-REIs overall, but REI quintuplets fell significantly, and NREI has not.