Periods 101 - Understanding the Menstrual Cycle: Phases, Hormones, Symptoms & Tracking

The menstrual cycle is a natural biological process that occurs in individuals with a uterus, usually every 21 to 35 days. It involves a series of hormonal changes that prepare the body for pregnancy. Understanding the menstrual cycle helps in tracking fertility, recognizing health issues, and improving overall reproductive health awareness.

What Is the Menstrual Cycle?

The menstrual cycle is the monthly process the body goes through to prepare for pregnancy. It is controlled by hormones and involves changes in the ovaries and uterus.

• Average Length: 21-35 days (28 days is common, but not required)

• Cycle Day 1: The first day of bleeding (start of your period)

• Main Hormones: Estrogen, Progesterone, Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH)

The Four Phases of the Menstrual Cycle

Phase 1: Menstrual Phase (Days 1-5)

• The uterine lining sheds.

• Bleeding occurs (your period).

• Hormone levels are low.

• Common symptoms: cramps, fatigue, low energy.

Phase 2: Follicular Phase (Days 1-13)

• Begins on the first day of your period and overlaps with the menstrual phase.

• FSH stimulates the ovaries to mature an egg.

• Estrogen levels rise.

• The uterine lining begins to rebuild.

• Energy and focus may increase toward the end of this phase.

Phase 3: Ovulation (Around Day 14 in a 28-day cycle)

• An egg is released from the ovary.

• Triggered by a surge in LH.

• The egg lives about 12–24 hours.

• This is the most fertile time of the cycle.

• Some people experience mild lower abdominal pain (ovulation pain).

Phase 4: Luteal Phase (Days 15–28)

• Progesterone increases.

• The uterus prepares for possible pregnancy.

• If fertilization does not occur, hormone levels drop.

• PMS symptoms may appear (mood swings, bloating, headaches).

• The next period begins, starting a new cycle.

Hormones and Their Roles

• Estrogen: Builds up the uterine lining and supports egg development.

• Progesterone: Maintains the lining after ovulation.

• FSH: Stimulates egg development in the ovaries.

• LH: Triggers ovulation.

Fertility and Pregnancy

• Pregnancy can occur if sperm fertilizes the egg during ovulation.

• Sperm can survive inside the body for up to 5 days.

• If fertilization happens, the fertilized egg implants in the uterus.

• If not, the uterine lining sheds during the next period.

Common Physical & Emotional Changes Throughout the Cycle

• Changes in energy levels

• Mood shifts

• Changes in appetite

• Breast tenderness

• Acne

• Changes in vaginal discharge

Irregular Menstrual Cycles

Cycles may vary due to:

• Stress

• Weight changes

• Hormonal conditions (e.g., PCOS)

• Thyroid disorders

• Birth control use

• Adolescence or approaching menopause

How to Track your Menstrual Cycle

Tracking can help you understand your body better. You can:

• Mark the first day of each period

• Track symptoms and moods

• Use a calendar or app

• Notice patterns over time

You can use the PeriodSakhi App to track your cycle and monitor your periods, ovulation, symptoms, and overall menstrual health with ease.

Benefits of Understanding Your Menstrual Cycle

Understanding your menstrual cycle can help you:

• Identify your fertile window for pregnancy planning or prevention

• Recognize hormonal imbalances early

• Track physical and emotional health changes

• Manage PMS symptoms more effectively

• Improve overall reproductive health awareness

When to See a Doctor

• Cycles regularly shorter than 21 days or longer than 35 days

• Severe pain that disrupts daily activities

• Very heavy bleeding

• Missing periods (not pregnant)

• Bleeding between periods

The menstrual cycle is a normal and healthy part of reproductive health. Every person’s cycle is different, and variation can be completely normal.

FAQs

What are the four phases of the menstrual cycle?

The four phases are the menstrual phase, follicular phase, ovulation, and luteal phase. Each phase is controlled by hormonal changes that prepare the body for possible pregnancy.

When is a woman most fertile during her cycle?

Fertility is highest during ovulation, which typically occurs around day 14 in a 28-day cycle. The fertile window includes the few days before and the day of ovulation.

What causes irregular menstrual cycles?

Irregular cycles can be caused by stress, hormonal imbalances, thyroid issues, PCOS, weight changes, or use of birth control.