When the Math Ain’t Mathing: How Too Many Mosaics Can Hurt Pregnancy Rates

Send us Fan MailIn this episode of Taco Bout Fertility Tuesday, Dr. Mark Amols breaks down one of the most overlooked problems in modern fertility care: the hidden harm of overcalling mosaic embryos.We begin with a surprising math puzzle from a 2023 study by Dr. Jonah Bardos in Fertility & Sterility, where the lab reporting the highest euploid rate also had the highest live birth rate—a result that shouldn’t happen if “more abnormal embryos were slipping through.” Instead, the math points to something deeper.Dr. Amols explains what mosaicism really is, why true biological mosaicism is rare, and how PGT-A testing can create artificial mosaics from noise, amplification variability, and overly sensitive algorithms. When labs generate inflated mosaic rates—sometimes 10–20%—they push potentially strong embryos out of the euploid category and unintentionally create selection bias.Through clear examples and memorable analogies, you’ll learn how calling too many mosaics doesn’t protect patients—it can actually lower pregnancy rates by changing which embryos get transferred first. You’ll also hear why high-level mosaics can be clinically useful, while overcalling low-level mosaics can distort decision-making and delay success.If you’ve ever felt overwhelmed or confused by mosaic results on a PGT report, this episode will help you understand what’s signal, what’s noise, and why more information isn’t always better in fertility care.Stay tuned at the end for ways to support the podcast and for a preview of an upcoming episode on high-level mosaics.Thanks for tuning in to another episode of 'Taco Bout Fertility Tuesday' with Dr. Mark Amols. If you found this episode insightful, please share it with friends and family who might benefit from our discussion. Remember, your feedback is invaluable to us – leave us a review on Apple Podcasts, Spotify, or your preferred listening platform.Stay connected with us for updates and fertility tips – follow us on Facebook. For more resources and information, visit our website at www.NewDirectionFertility.com.Have a question or a topic you'd like us to cover? We'd love to hear from you! Reach out to us at [email protected] us next Tuesday for more discussions on fertility, where we blend medical expertise with a touch of humor to make complex topics accessible and engaging. Until then, keep the conversation going and remember: understanding your fertility is a journey we're on together.