Understanding your menstrual cycle is one of the most important steps in taking control of your reproductive health. Whether you're trying to conceive, planning ahead, or simply want to better understand your body, knowing what’s “normal” and when you’re most fertile can make a significant difference.
In this guide, we’ll break down the typical length of the menstrual cycle, explain when ovulation occurs, and highlight the key fertility window, all while addressing common misconceptions.
What Is a “Normal” Menstrual Cycle?
A normal menstrual cycle can vary from person to person, but for most women, it typically lasts between21 and 35 days. The average cycle length is often cited as 28 days, but this isn’t the standard for everyone.
Key Phases of the Menstrual Cycle
Your cycle is divided into four main phases:
1. Menstrual Phase (Days 1–5)
This is when your period occurs — the shedding of the uterine lining.
2. Follicular Phase (Days 1–13)
Overlaps with menstruation at the start. Hormones stimulate the ovaries to prepare an egg for release.
3. Ovulation (Around Day 14 in a 28-day cycle)
The ovary releases an egg, which travels down the fallopian tube.
4. Luteal Phase (Days 15–28)
The body prepares for pregnancy. If fertilisation doesn’t occur, hormone levels drop and the cycle restarts.
When Are You Most Fertile?
The most fertile time in your cycle is known as the fertile window. This includes:
- The day of ovulation
- The 5 days leading up to ovulation
This means you are typically most fertile around days 10 to 15 in a 28-day cycle, though this varies depending on your cycle length.
Why Is This the Fertile Window?
- Sperm can survive in the reproductive tract for up to 5 days
- The egg survives for 12–24 hours after ovulation
Having intercourse before ovulation increases the chances that sperm will already be present when the egg is released.
Signs You’re Ovulating
Recognising ovulation symptoms can help you identify your most fertile days:
- Changes in cervical mucus (clear, stretchy, egg-white consistency)
- Slight increase in basal body temperature
- Mild pelvic or abdominal pain (sometimes called ovulation pain)
- Increased libido
Tracking these signs can improve your understanding of your fertility patterns.
How to Track Your Cycle
There are several effective ways to monitor your cycle and predict ovulation:
- Cycle tracking apps
- Ovulation predictor kits (OPKs)
- Basal body temperature charting
- Cervical mucus observation
Consistency is key; tracking over several months gives a clearer picture of your individual cycle.
What If Your Cycle Isn’t Regular?
Irregular cycles are common and can be caused by:
- Stress
- Hormonal imbalances
- Polycystic ovary syndrome (PCOS)
- Thyroid disorders
- Significant weight changes
If your cycle is consistently shorter than 21 days, longer than 35 days, or unpredictable, it may be worth seeking professional advice.
When to Seek Fertility Support
You may want to consult a fertility specialist if:
- You’ve been trying to conceive for 12 months (or 6 months if over 35)
- Your cycles are irregular or absent
- You have known reproductive health conditions
Early guidance can help identify any underlying issues and improve your chances of conception.
Every menstrual cycle is unique, and understanding yours is a powerful tool. Knowing how long your cycle lasts and when you’re most fertile can help you make informed decisions, whether you're trying to conceive now or planning for the future.
If you have concerns about your fertility or would like personalised support, speaking to a specialist can provide clarity and reassurance. Speak to our Patient Advisors on 0161 958 6142, or self-refer online here if you’d like to have private fertility treatment with Manchester Fertility.
Last updated: 30th March 2026
