For this analysis, women who elected to terminate their pregnancy before term for any reason were excluded. Patients were then categorized into 3 mutually exclusive groups: those who underwent an invasive ART procedure in this pregnancy, including the use of in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), gamete intrafallopian transfer or zygote intrafallopian transfer (n = 554), women who used a noninvasive ART procedure only, such as ovulation induction or intrauterine insemination (n = 1,222); and control patients who did not undergo any ART procedure (n = 34,286).