How does the menstrual cycle affect fertility?
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The menstrual cycle varies in length among women, with an average of 28 days between periods. It’s normal for cycles to range from 23 to 35 days.

To learn about the menstrual cycle, first understand the reproductive organs within a woman’s body, including:

  • the two ovaries where eggs are stored
  • the womb (uterus), where a fertilised egg can develop into a baby
  • the fallopian tubes connecting the ovaries to the womb
  • the cervix serving as the entrance to the womb from the vagina

Menstrual Cycle: Role of Oestrogen

Rising oestrogen levels in each cycle stimulate the ovary to develop and release an egg (ovulation), causing the womb lining to thicken. In the latter part of the cycle, progesterone helps prepare the womb for potential embryo implantation. If pregnancy doesn’t occur, oestrogen and progesterone levels decrease, leading to the shedding of the womb lining, resulting in a period.

A typical period consists of blood and the uterine lining, with the first day of bleeding considered day 1 of the menstrual cycle. Periods usually last 2 to 7 days, during which women typically lose 20 to 90ml of blood. Some women may experience heavier bleeding, and support is available for managing heavy periods.

Ovulation and Its Significance

Ovulation, the release of an egg from the ovaries, is a significant event in the menstrual cycle. Women are born with all their eggs and one egg typically develops and is released during each menstrual cycle. Pregnancy can occur if a man’s sperm fertilises the egg.

Sperm can remain viable in the fallopian tubes for up to 7 days after intercourse. Occasionally, more than one egg is released during ovulation, potentially leading to multiple pregnancies, such as twins. Certain hormonal contraceptives, like the combined pill, contraceptive patch, and contraceptive injection, prevent ovulation to prevent pregnancy.

When Are You Most Fertile?

The most fertile period for women is typically around the time of ovulation. While pinpointing the exact timing of ovulation can be challenging, it generally occurs about 10 to 16 days before the next expected period. Women with regular 28-day cycles are likely to be fertile around day 14 of their cycle although this may vary for those with shorter or longer cycles.

Throughout the menstrual cycle, vaginal secretions, also known as vaginal discharge, change. Around ovulation, these secretions become thinner and stretchy, resembling raw egg whites. If you have concerns about changes in your vaginal discharge, consider consulting a private gynaecologist in London for guidance.


Treloar A.E., et al. Variation of the human menstrual cycle through reproductive life. Int J Fertil. 1967;12(1 Pt 2):77–126. [PubMed]

Mahantesh Karoshi
Mahantesh Karoshi

I'm a Consultant Obstetrician & Gynaecologist and Women's Health Expert. I believe in educating my patients to contribute to achieving the best possible clinical and holistic outcomes. By taking this approach, I enable and empower my patients whilst addressing their issues and concerns. I run a private practice with an extremely high standard of professionalism. My patients are directly involved in their care and management in all stages. My approach to my patient's problems is built on dedication and passion, drawing on analytical thinking and my on-time honored reading, teaching medical professionals nationally and internationally.