Couple to Couple League’s Fertility Science Institute Warns of Harmful Content in Mainstream Fertility Apps and Introduces PeakDay
New app offers women of all ages trustworthy, science-based fertility tracking without the morally problematic features common in many popular platforms
The Fertility Science Institute by Couple to Couple League, a leading provider of Natural Family Planning (NFP) resources, is launching an updated version of PeakDay, its Catholic fertility and period-tracking app, which has already been downloaded nearly 200,000 times in the past year. Designed as a safe, values-driven alternative to mainstream fertility apps that often promote birth control, abortion, and other controversial agendas, PeakDay empowers women to track their fertility while staying true to their Catholic beliefs. To start 2026, women are invited to take a 60-day personal challenge to improve cycle health, with a free trial of PeakDay’s premium features included.
“The good news is that millions of women and teens are seeking ways to understand their bodies and track their cycles naturally, without medical intervention,” said Katie Zulanas, Executive Director of Couple to Couple League. “The challenge is that many mainstream apps flood users with ads and content that are misleading, inappropriate, or inconsistent with Church teaching, and too often they sell personal data that exposes women to further unwanted or harmful information. PeakDay offers a Catholic alternative that helps women and couples live in harmony with their bodies and their faith– in a way that’s modern, private, and deeply personal.”
The surge in PeakDay downloads over the past year reflects a growing interest in natural fertility informed by faith. For many women, the app serves as an introduction to the broader resources offered by the Fertility Science Institute (FSI), a one-of-a-kind comprehensive online platform that provides scientifically-based resources to millions of Fertility Awareness-Based Method (FABM) users. These include Start to Chart programs for young adults, Mother–Daughter courses, and their signature NFP classes for couples. FSI also maintains a robust YouTube channel, where its Peak Life Show—a guest-driven nutrition and lifestyle series hosted by Viva Crouse—has earned more than three million views in the past six months.
The PeakDay app is free for women who want a simple way to track their periods and chart ovulation patterns. The premium version offers expanded features, allowing women to record detailed cycle and health information to better identify their fertility phases and determine overall cycle trends and stats. Additionally, women can access a community of fertility coaches for personalized support and share their charts with an instructor or medical professional. All data syncs across multiple devices, enabling both husband and wife to participate in the charting process and grow together in fertility awareness. It also connects with popular health and fitness trackers like Oura Ring, Fitbit, and Apple Watch.
“A new year is the perfect time to set goals and assess our health, and a woman’s cycle can be one of the strongest indicators of overall wellness,” said Zulanas. “PeakDay gives women the tools to take control of their fertility, and FSI is offering a free 60-day trial to start this journey for 2026.”
For more information, visit https://peakday.com/try/.
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The Couple to Couple League is an international non-profit organization established in 1971 that is dedicated to inspiring, educating, and supporting couples in family planning that is natural, effective, healthy, and consistent with God’s plan for life, love, and marriage.
