The Menstrual Cycle Hormones, Health, and Fertility

The menstrual cycle is a finely tuned biological process regulated by hormonal changes. It consists of several phases, from menstruation through the follicular and ovulation phases to the luteal phase. It influences not only fertility but also a woman’s mood, energy, nutrition, and overall physical well-being.

All About Your Menstrual Cycle: Phases, Functions, and Its Importance for Your Health

The Menstrual Cycle

Influencing Factors: What Can Affect Your Menstrual Cycle

Factors Affecting Your Cycle

The article explores why the common belief in a 28-day cycle doesn't apply to most women.

Cycle Length & Duration

The Menstrual Cycle – Phases, Hormones and How They Shape Your Body and Wellbeing

Your menstrual cycle is so much more than just your period and ovulation. It's a finely tuned biological process that influences nearly every aspect of how you feel physically and emotionally – your energy levels, mood, sleep quality, appetite, focus and even your skin.

The Four Phases of the Menstrual Cycle

Menstrual Phase (approx. days 1–5) Your uterine lining sheds. Estrogen and progesterone are at their lowest. Many women feel fatigued and want to slow down during this phase – and that's completely normal. Your body is doing real work.

Follicular Phase (approx. days 1–13) Starting on day one of your period, the follicular phase begins. Estrogen rises, mood lifts, and energy and focus start to build. This is prime time for new projects, harder workouts and social plans.

Ovulation Phase (approx. day 14) Ovulation is the peak of your cycle. A mature follicle releases an egg, which travels into the fallopian tube. Your fertile window spans several days around ovulation. Daysy's all-in-one fertility tracker detects this window precisely through daily BBT measurement – no guessing, no ovulation strips needed.

Luteal Phase (approx. days 15–28) Progesterone takes over. Your body prepares for a possible pregnancy. This is when PMS symptoms can show up – mood swings, cravings, bloating. That's biology, not a flaw. Understanding this phase helps you work with your body instead of against it.

Hormones – the Architects of Your Cycle

FSH, LH, estrogen and progesterone orchestrate your entire cycle. Their interplay determines fertility, emotional wellbeing and the timing of ovulation. Every morning, Daysy measures the direct impact of these hormonal shifts on your basal body temperature and interprets that data scientifically – giving you a clear, reliable picture of where you are in your cycle each day.

In the cycle health section on the Daysy website you'll find in-depth articles on every phase, the hormones behind them, and how your cycle affects everything from workout performance and nutrition to energy and sleep.

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