Revised clinicaltrials.gov protocol. The original study design was proposed and funded during the era when guidelines from the American College of Obstetricians and Gynecologists (ACOG) regarding access to prenatal testing differed by maternal age stratum (less than 35 years at the age of delivery versus 35 years or older). Our original primary hypothesis posited that the effect of IFC would increase invasive test use among women who were less than 35 years old while decreasing invasive test use among women 35 years or older. The thought underlying this hypothesis was that the younger women, who traditionally were not informed of this option, and for whom insurance coverage for these procedures was not consistently available, would increase their overall invasive test use if these informational and financial barriers to were removed in the context of the study. On the other hand, women 35 years and older, for whom the offer of invasive diagnostic testing was considered routine, would become more informed about the risks and benefits of both screening and invasive diagnostic testing, would be less likely to default to invasive testing. The original sample size estimate was N=1200 women.