Understanding the Menstrual Cycle: What’s Normal and What’s Not

Periods are a natural part of life, yet many women aren’t sure what counts as a “normal” cycle. While every woman’s body is different, understanding how the menstrual cycle works - and recognising when something feels off - is an important part of protecting your reproductive health. 

The Basics of the Menstrual Cycle

The average menstrual cycle lasts about 28 days, although anything from 21 to 35 days can still be normal. The cycle is counted from the first day of one period to the first day of the next. It is divided into four key phases: 

1. Menstrual Phase (Days 1–5): This is when bleeding occurs as the uterine lining sheds. 
2. Follicular Phase (Days 1–13): Hormones like FSH stimulate the ovaries to produce follicles, one of which will mature into an egg. 
3. Ovulation (Day 14 in a typical cycle): A surge of luteinising hormone (LH) causes the release of an egg, which can be fertilised for pregnancy. 
4. Luteal Phase (Days 15–28): Progesterone levels rise to prepare the uterus for a possible pregnancy. If no fertilisation occurs, hormone levels drop, and the cycle begins again. 

What’s Considered Normal? 

• Cycle Length: 21–35 days. 

• Bleeding Duration: 3–7 days. 

• Blood Flow: Around 30–80ml per cycle (roughly 3–5 pads or tampons per day). 

• Symptoms: Mild cramping, mood changes, or breast tenderness may occur but should not be debilitating. 

If your cycles follow this general pattern, it’s usually a sign that your reproductive system is working as it should. 

Signs That Something May Not Be Normal

It’s important to pay attention to changes in your cycle. Some symptoms that may indicate an underlying gynaecological condition include: 

• Very Heavy Periods (Menorrhagia): Needing to change pads or tampons every hour, passing large clots, or bleeding for more than 7 days. 

• Irregular Cycles: Periods that are unpredictable, too close together, or absent altogether. 

• Severe Pain: Cramps that interfere with daily life may be linked to endometriosis, fibroids, or pelvic inflammatory disease. 

• Spotting Between Periods: Could be related to hormonal issues, cervical changes, or infections. 

• Missed Periods: Pregnancy is the most common reason, but thyroid problems, PCOS, or stress can also disrupt cycles. 

If you experience any of these symptoms, a gynaecology consultation can help identify the cause and provide treatment options.

The Role of Hormones

Hormones such as oestrogen, progesterone, FSH, and LH regulate each stage of the cycle. Even small imbalances can have a big impact, causing irregular cycles, mood changes, or difficulties conceiving. Blood tests can measure hormone levels and give valuable insight into reproductive health. 

Our clinic offers private hormone profiles and ultrasound scans that provide clarity if your cycle feels irregular. 

Lifestyle Factors That Influence Your Cycle

Your menstrual cycle can also be affected by lifestyle factors such as: 

• Stress: High stress can delay or even stop ovulation temporarily. 

• Weight Changes: Being underweight or overweight can affect hormone balance. 

• Exercise: Excessive physical training sometimes leads to missed periods. 

• Contraception: Hormonal contraception can change bleeding patterns, sometimes making periods lighter, heavier, or absent. 

If you notice sudden or lasting changes after a lifestyle shift, it may be worth discussing them with a gynaecologist. 

Why Monitoring Your Cycle Matters?

Tracking your cycle helps you spot patterns, prepare for symptoms, and recognise when something feels unusual. Whether you’re trying to conceive, approaching menopause, or simply want reassurance, understanding your cycle gives you control over your health. 

Final Thoughts

Every woman’s cycle is unique, but knowing what’s typical - and when to seek advice - is the key to maintaining good reproductive health. If you experience heavy bleeding, severe pain, irregular cycles, or other concerning changes, it’s best not to ignore them.

For Expert Support and Answers

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