Topic hub
Cycle & Menstrual Health
A textbook cycle is 28 days; real cycles mostly aren't, and that's usually fine. This hub explains the four phases, what's actually normal, how ovulation prediction really works, and why cycle data is medical data that belongs on your own device. Calm, factual, zero euphemism — and never a substitute for a clinician.
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Start here — free mini-course
A free 6-part course on cycle literacy — the four phases, what's normal, real ovulation math, PMS and PMDD, and keeping your cycle data private.
6 of 6 lessons available now — new lessons weekly.
Guides in this hub
The Four Phases of Your Menstrual Cycle, Properly Explained
The menstrual cycle is far more than a monthly timer. Understanding its four distinct phases — and why the textbook 28-day model misleads most people — is the foundation of real cycle literacy.
What Is a "Normal" Cycle? (Wider Than You Think)
Most cycles that people worry about fall comfortably within the normal clinical range. Here is what that range actually is — and the small set of patterns that genuinely warrant medical attention.
Ovulation and the Fertile Window: The Real Math
The fertile window is six days long, sperm survive up to five of them, and ovulation rarely happens on day 14. Here is the biology — and a frank note on what tracking apps can and cannot do.
PMS, PMDD and the Luteal Phase: What's Actually Happening
Feeling worse in the two weeks before your period is not in your head — there is a clear hormonal mechanism. Here is what it is, what helps, and when PMS becomes something clinically different.
Your Cycle Data Is Medical Data: Privacy 101
Cycle data can reveal pregnancy, fertility, health conditions, and reproductive intentions. Here is why it deserves the same care as your most sensitive medical records — and what to look for in an app.
Tracking Your Cycle for Insight: Making Your Data Useful
Tracking your cycle becomes genuinely useful only when you know what to log, why each field matters, and how to read three cycles of data rather than just accumulate it.
Put it into practice with Marigold
Marigold is a private, offline period & cycle tracker for Android with clear predictions and a beautifully labeled cycle ring. No account, no cloud.
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