Wondering what the menstrual cycle is, and what it means for you and your body? Understanding your menstrual cycle can improve your menstrual health, well-being, and sex life.
This article is written by medical practitioner Dr Alice Byram. Read more about Dr Alice Byram at the end of the article.
What is your menstrual cycle?
Your menstrual cycle is the time your body cycles through the hormones that prepare the womb or uterus for a potential pregnancy. Your body is under the influence of various hormones which give you the ability to become pregnant and provide the right environment for the embryo should you become pregnant.
The length of a menstrual cycle can vary from 21 days to 40 days and still be considered normal. The first day of your menstrual cycle is counted from the day you start bleeding until the next time your period starts. All bodies are different, so the length of your own menstrual cycle may be shorter or longer and not all menstrual cycles are regular.
The menstrual cycle is split into two phases and 4 different points, controlled by hormones.
What is happening in your body: This corresponds to your period and the breakdown of the uterus wall lining which has not been needed as you are not pregnant. As you can see above, this is in response to a drop of progesterone (Pro-gestation or pro-pregnancy) hormone at the end of the previous menstrual cycle if you did not become pregnant.
How having your period can affect you: Apart from managing the bleeding with an efficient menstrual product such as a menstrual cup, you may also be experiencing period cramps or low energy. The intensity varies from person to person but our tips to relieve period cramps can help you
2. Proliferative / Follicular phase:
What is happening in your body: In this phase, the egg is being prepared to be released, under the influence of FSH (follicle-stimulating hormone). Oestrogen prepares the lining of the uterus or womb wall for the potential implantation of an embryo should you become pregnant.
How this can affect you: Increasing oestrogen levels can make you feel more energised but this varies from person to person and it is not clear how changes in oestrogen affect our energy and moods.
What is happening in your body: The mature egg is released from the fallopian tubes and travels down to the uterus.
How this can affect you: This is your most fertile period as it is the easiest time for a sperm to fertilize an egg and for you to become pregnant. Your libido or sex drive may be increased.
4. Secretory / Luteal phase.
What is happening in your body: This part of your cycle is under the influence of progesterone and the uterus wall is maintained to enable any fertilized egg to receive the nutrition it needs.
How this can affect you: You may feel more irritable or moody and have PMS.
What happens to my body if I become pregnant?
If a male sperm fertilises a female egg after penetrative sexual intercourse without contraception then you become pregnant. Sometimes even if you do use contraception you can become pregnant. At this point there is an increase in the progesterone (or pro-gestation) hormone and instead of the uterus wall lining breaking down and you having your period, the wall becomes thicker.
Can I still get pregnant if I have my period?
Yes! As many women will tell you, having your period is no guarantee that you will not become pregnant. This is because sperm can last up to 7 days in your body and by that point, you may already be fertile with your next cycle.
Do I need to use contraception even when I am not “fertile”?
Yes! Although your maximum fertility are the days around the time when the egg is released, you can still get pregnant at any other time in your cycle. This is because as we explain above a combination of sperm lasting longer than you might think plus being at a different time in your menstrual cycle than you have calculated can lead to an unexpected pregnancy.
How do I know when my next period is due?
Everyone is different but knowing your own body will help you deal better with all the different aspects of your menstrual cycle, whether it be PMS or your period and period product. Tracking your menstrual cycle will also help you identify any changes for which you may need to consult your doctor. You can use a mobile app or an old fashioned mark on a calendar and look at your average cycle length over the past 3 months. You then get an idea of when your next period and PMS are due. However, this is not set in stone and there are many reasons that your menstrual cycle can vary from month to month. Tracking your period helps you plan ahead and avoid unwanted surprises, and you’ll know exactly when to bring your menstrual cup along.
How many periods will I have in a lifetime?
Your first period is called the menarche and your last period is the menopause. The time around having your last period is called the perimenopause and has its own set of symptoms. The menarche or first period happens during puberty which can start as early as 8 years or as late as 151. So if you work out that you have an average of 451 periods in your lifetime (if you are a Dutch woman)2, choosing the right menstrual product which is both financially and ecologically viable is important. Menstrual cups have a duration of up to 10 years making them the most sustainable and affordable period product whichever stage of your reproductive life you are.
During your period be sure to use a period product you feel comfortable with. If you’ve been using tampons or pads but didn’t feel happy with the solution, look into our Ruby Cup made of 100% medical grade silicone (no bleaches, perfumes or other chemicals) and through each cup purchased, we donate another one to someone who is unable to afford safe period products.
Date last reviewed: April 2020
Written by Dr Alice Byram Bsc Med & Surg UMA MA Hons MML Cantab
Dr Alice Byram was born in England to a French-British family. Following on from a degree in Spanish from the University of Cambridge, she went to Spain to study medicine. On her return to the UK, she worked in Emergency Medicine for several years before recently returning to Barcelona.
1 Klein DA, Emerick JE, Sylvester JE, Vogt KS. Disorders of Puberty: An Approach to Diagnosis and Management. Am Fam Physician. 2017;96(9):590–599.
2 Chavez-MacGregor M, van Gils CH, van der Schouw YT, Monninkhof E, van Noord PA, Peeters PH. Lifetime cumulative number of menstrual cycles and serum sex hormone levels in postmenopausal women. Breast Cancer Res Treat. 2008;108(1):101–112. doi:10.1007/s10549-007-9574-z