Our Reproductive Health guide empowers you with knowledge so you truly understand your body and ensure you are receiving the best medical treatment for any problems you may be experiencing. Good reproductive health is crucial for general health and taking positive action now lays the foundations for lifelong health. Reliable scientific information underpins everything we do and helps you take control of your wellbeing.
Hormones and the menstrual cycle have a huge impact on the lives of women and people who menstruate, and yet we are not routinely taught from a young age how to tell if our periods are normal. When problems arise, this can cause unnecessary and prolonged suffering as pain and symptoms are often dismissed as normal, even by doctors. Understanding your body is a skill for life that can help protect your health and wellbeing from menstruating to menopause and beyond.
In this section, we look at:
- What is a menstrual period?
- What does a healthy period look like?
- Are my periods normal?
- Menarche – when your periods start
- Irregular periods
- Heavy periods
- Light Periods
- Premenstrual syndrome (PMS)
- Premenstrual dysphoric disorder (PMDD)
- Assessing your menstrual cycle when your periods stop unexpectedly
- Causes of amenorrhoea – hypogonadotrophic hypogonadism
- How diet and exercise affect your periods
- Periods and fertility
- Impact of the oral contraceptive pill on your periods
- Menopause – when your periods stop
What is a menstrual period?
A menstrual period happens when the lining of the uterus (the endometrium) falls away as part of a normal menstrual cycle. The endometrium develops during the menstrual cycle in preparation for a pregnancy but then subsequently sheds if the egg released during ovulation is not fertilised. The endometrium starts to break down when progesterone and oestrogen fall as these hormones are needed to maintain it. The lining is then lost over a few days as menstrual blood and this is your menstrual period.
The menstrual cycle is divided into four main phases (menstruation, follicular phase, ovulation and luteal phase) and the first day of your period is day one of your cycle. You can learn more about the menstrual cycle including the hormones controlling it in the Female Fertility and The Fertile Window sections.
What does a healthy menstrual cycle look like?
When it comes to fertility, a healthy menstrual cycle is a regular cycle typically between 25 and 35 days in length, with mostly continuous moderate bleeding that is mainly bright red in colour of 2–5 days’ duration with a definite start.
Are my periods normal?
For good menstrual health and fertility, it’s helpful to understand whether or not you have symptoms that may indicate a problem. A healthy menstrual cycle is the foundation for good fertility and an indicator of general health, so understanding your periods can help you assess what may be happening in your body. It is always important to seek medical advice rather than rely on self-diagnosis but being informed and empowered to play your part in your own healthcare rather than being a passive recipient is an important feature of progressive medicine.
If you have spotting in the days leading up to your period, you need to consistently use more than one sanitary product every four hours, there are large clots in the blood, you suffer pain that cannot be managed with over-the-counter painkillers and a hot water bottle, you experience a very irregular cycle or have abdominal pain that persists throughout your cycle, these are all signs that something may need addressing. Cycles shorter than 25 days mean that you may have a short luteal phase, which may contribute to difficulties conceiving and may indicate low levels of the progesterone needed to sustain a pregnancy.
While some of these symptoms can be common, it does not mean they are necessarily normal, and you should not accept them as such without trying to get to the bottom of what may be causing the issue. It is common for patients with endometriosis to report that their severe pain was described as normal period pain when they first sought medical help, leading to a delay in diagnosis, for instance. We have also seen incidences of premature ovarian insufficiency (an early menopause) being missed as skipping a period is seen as normal, with sometimes not even the red flag of a very high follicle stimulating hormone (FSH) blood test result recognised as serious.
Delays in diagnosing underlying conditions mean that at best suffering and infertility is unnecessarily prolonged and, at worst, can cost you your ability to have your own biological children. Historically, of course, many aspects of female reproductive health and fertility have not been taught fully in schools. As a result, a lack of fundamental knowledge among women of the workings of their own bodies remains a significant source of disempowerment and we are passionate about educating girls and women to correct this.
Menarche – when your periods start
The age at which you start your periods is influenced by a combination of genetic and environmental factors, the most significant being nutritional status, body mass index (BMI), genetic predisposition and exposure to endocrine disrupting chemicals (EDCs – chemicals that disrupt hormones). Though there is natural variation – some girls start as young as nine and others up to around fourteen years – if you have passed your fifteenth birthday and still have not started your periods, you should consult your doctor, especially if there are no signs of puberty at all including breast development.
Higher body weight is an important factor in bringing on an early puberty with girls who are overweight starting their periods sooner. One study investigating timing of puberty involving over 73,000 students (over 40,000 of which were girls) found the average age of menarche was 11.71 years and this was lower in girls who were overweight or obese. Leptin is a hormone that is important both in terms of weight and metabolism but also for reproductive function and it plays an important role in the start of puberty. This hormone indicates how much fat you have (the greater the body fat, the more leptin you will have) and also signals to your body that you have enough body fat to become sexually mature (and so sustain a pregnancy). Leptin, body weight and nutritional status therefore play a role in ensuring your body is ready to meet the demands of reproduction and so ready for puberty to begin. Nutritional status means how well-nourished you are in terms of both macronutrients (fat, protein and carbohydrates) and micronutrients (vitamins, minerals and essential fatty acids) and of course both are important in ensuring you have enough of both for the development of the baby if you become pregnant.
Conversely, low body weight can delay puberty and mean you start your periods later. This can be caused be under-eating, over-exercising or conditions that impact your body weight and nutritional status like coeliac disease, which can impact fertility and increase the risk of miscarriage. These same factors can also cause periods to stop once they have started (amenorrhoea), so diet and lifestyle are important factors to consider if this happens to you. The importance of understanding these issues comes into very sharp focus when trying to conceive, but they are vital for the well-being of all women and people who menstruate at any life stage.
Irregular periods can be caused by a number of different factors and these include:
- Polycystic ovary syndrome (PCOS)
- Hormone imbalances
- Low body weight
- Premature ovarian insufficiency (POI) – an early menopause
- Thyroid conditions
- Coeliac disease
Note that periods can be irregular in the year or two after menarche and this is not usually a sign of a problem. They often settle down but if this doesn’t happen after two years, or if you have started your period later than average (14-15 years or older) and your periods are very irregular, this needs investigating.
If your periods are irregular, it’s important to understand why, so we recommend taking the following steps:
- Have the necessary investigations including hormone testing to rule out or help diagnose PCOS and screening for coeliac and thyroid disease
- Test for pregnancy
- Eat more/gain weight
- Nutrient testing
Very heavy periods can signal problems and may indicate that you are not ovulating. Your periods are classed as heavy if you routinely need to use more than four sanitary products per day or more than one product overnight or leak overnight. Some common causes of heavy periods include:
- High oestrogen
- High BMI
If you’re suffering with heavy periods, this can have a significant impact on your quality of life and it’s important to identify if there is an underlying problem. We recommend taking the following steps:
- Have the necessary investigations including hormone testing
- Diet and lifestyle to support hormone metabolism and reduce inflammation
- Consider weight loss if needed
- Nutrient testing
Also note that heavy periods or prolonged periods (more than 5 days) will also deplete certain nutrients, especially iron due to the increased loss of blood each month. Testing your ferritin levels (a measure of the iron store in your body) and supplementing with iron are often needed.
Very light periods (where you need to use less than three sanitary products daily) can also indicate problems and can be caused by:
- Low oestrogen
- Low BMI
We recommend taking the following steps:
- Diet and lifestyle to support hormone metabolism and adequate nutrient levels
- Consider weight gain if needed
- Stop smoking
- Vitamin E can help if you are trying to conceive and the endometrium is also thin
Premenstrual syndrome (PMS)
PMS is the collection of symptoms many women experience just before a menstrual period. These include:
- Breast tenderness
- Abdominal cramping
- Mood swings
- Feeling tearful, anxious or irritable
- Bloating or tummy pain
- Spots and acne
- Changes in appetite and sex drive
PMS can be worse if you have:
- High oestrogen
- Low progesterone
You can take steps to improve PMS symptoms:
- Using diet and lifestyle to support hormone metabolism and reduce inflammation
- Strategies to deal with stress
- Consider supplements including vitamin B6, zinc, magnesium, evening primrose oil
Premenstrual dysphoric disorder (PMDD)
PMDD is a more serious form of PMS where symptoms become very debilitating and this can affect mental health. Symptoms include very severe pain before and during periods often with strong cramping and other symptoms, such as sweating, headaches, nausea, vomiting, and diarrhoea. Your risk of developing more severe symptoms increases if you started your periods at a younger age, you have prolonged menstrual bleeding or heavy menstrual flow, you smoke or have a family history. Although overall women using oral contraceptive pills (OCP) report less serious symptoms, women suffering from the most extreme forms of PMDD sometimes have to resort to a hysterectomy (surgical removal of the uterus) to escape the pain and suffering, so more research is needed to provide better treatment options.
Assessing your menstrual cycle when your periods stop unexpectedly
If you have problems with your periods, you will usually need to see a doctor and you can find out more in our medical investigations section to ensure you have the appropriate assessments.
If you suffer from anovulatory infertility (infertility caused by not ovulating), you may either have a complete absence of any cycles (amenorrhea) or infrequent, irregular periods (oligomenorrhea), particularly if you have PCOS. Amenorrhea is sometimes known as primary – where periods never started – or secondary, that is, the periods have stopped. All causes of secondary amenorrhea can also cause primary amenorrhea, although there are some rare causes of primary amenorrhoea that will come to light if an adolescent doesn’t start her periods as expected. This can happen because important structures haven’t developed normally: for example, the hypothalamus or pituitary may be abnormal, the womb may not have developed at all or it may be there but there is a physical blockage preventing the flow of menstrual blood.
There are four main causes of absent or irregular periods:
- Hypogonadotrophic hypogonadism – see below
- High levels of prolactin
- PCOS, which is the most common and accounts for about 90 per cent of cases
- Ovarian insufficiency, which either causes periods to stop altogether or irregular periods in its early stages due to low anti-Müllerian hormone (AMH), the hormone sense therefore that a good diet can help improve symptoms and, although further research is needed, these studies certainly point towards an important role for nutrition in the health of the menstrual cycle.
One common reason for problems with periods and ovulation is something called hypogonadotrophic hypogonadism. This means low levels of the gonadotrophin hormones – follicle-stimulating hormone (FSH) and luteinising hormone (LH) – that cause the gonads (ovaries or testes) to stop working – ‘hypogonadism’ – and can be caused by problems either with the pituitary or hypothalamus.
The most common causes of hypogonadotrophic hypogonadism that lead to problems with periods and ovulation include:
- Being underweight: In women who are underweight, LH levels are often lower than FSH levels. Some women may gain weight and reach a normal BMI but still not resume regular periods. This is because sometimes the body resets itself and simply won’t start ovulating naturally, so you will need medication to help. Ongoing high intensity exercise can also continue to suppress your menstrual cycle.
- Eating disorders: Anorexia nervosa can impact FSH and LH levels and lead to amenorrhoea. Bulimia is another eating disorder that can affect fertility, and both conditions tend to cause problems with periods and ovulation. While fertility doctors can treat the physical aspects of these conditions, it’s important to seek psychological help to address the underlying causes and also support you during pregnancy.
- Exercise: Over-exercising can disrupt the menstrual cycle, and period problems are common in athletes undergoing intensive training. Between 10 and 20 per cent have oligomenorrhea or amenorrhea, compared with 5 per cent in the general population. Amenorrhea is particularly common in endurance athletes (e.g. with long-distance running). Up to half of competitive runners training 80 miles per week may have no periods. The main factors are low weight and percentage body fat, which is why gymnasts, runners and ballerinas tend to have greater problems than swimmers. The physiological changes are similar to those seen with starvation and chronic illness. You don’t have to be a professional athlete for exercise to cause problems, however, so always discuss your exercise levels with your doctor if you are having problems with your periods.
- Unknown cause: Sometimes the cause simply isn’t known (‘idiopathic hypogonadotrophic hypogonadism’) and we recommend following the dietary and lifestyle guidance we cover in our Fertility and Preconception Care course alongside medical treatment. Sometimes eating more can help, even if you are not underweight, but we recommend seeking professional advice first.
Rare causes of hypogonadotrophic hypogonadism include a tumour of the pituitary and/or hypothalamus, diseases such as tuberculosis and sarcoid, being overweight and Kallmann syndrome, a rare condition where the nerve cells that secrete gonadotrophin-releasing hormone (GnRH) from the hypothalamus to the pituitary fail to develop. Kallmann syndrome is diagnosed if periods have never started and FSH and LH levels are unrecordable; there is often also a deficiency of the sense of smell (anosmia) and/or colour blindness.
If you are found to have hypogonadotrophic hypogonadism (sometimes abbreviated as hypog hypog or simply HH), then you will first need hormone replacement therapy (HRT) to give you an artificial menstrual cycle and healthy levels of oestrogen until the time is right for you to start trying for a pregnancy, and then ovulation induction. If you are trying to conceive, it is not in the baby’s best interests to be pregnant when severely underweight as there is significant risk of intrauterine growth retardation (IUGR), prematurity, still birth and neonatal problems. Therefore, it is vital to first gain weight and correct any nutrient deficiencies and follow a preconception care programme before treatment and conception to prevent the avoidable risks to the unborn child.
How diet and exercise affect your periods
Nutrient levels, weight, stress, and exercise, can all impact your periods. Undereating and low body weight are both potential threats to optimal hormone levels and a healthy menstrual cycle, for instance. It is also believed that inadequate levels of certain nutrients may contribute to menstrual cycle dysfunction as studies indicate that supplementation can help improve symptoms. Nutrient requirements and metabolism also change with hormone fluctuations during the menstrual cycle.
Many pre-existing underlying health conditions, including diabetes and inflammatory bowel disease (IBD), get worse during the second half of the cycle if a woman hasn’t conceived that month, when oestrogen and progesterone levels start to fall again. This worsening coincides with lower levels of certain nutrients such as amino acids, which suggests that the body uses more of these nutrients during ovulation and the luteal phase, possibly in anticipation of a possible pregnancy. These lower nutrient levels are thought to contribute to symptoms of premenstrual syndrome (PMS) and, the more serious form, premenstrual dysphoric disorder (PMDD), which include premenstrual low mood and anxiety. It is no surprise therefore that PMS also brings increased appetite, food cravings and higher calorific intake. Levels of neurotransmitters associated with good mood (including serotonin) also fall in line with nutrient levels during the second half of the period. It makes sense therefore that a good diet can help improve symptoms and, although further research is needed, these studies certainly point towards an important role for nutrition in the health of the menstrual cycle.
Periods and fertility
Because a healthy menstrual cycle is the foundation for good fertility and important in making sure you are ovulating, working on your menstrual health and ensuring you have any medical care you may need while you are young can help make things easier when it comes to getting pregnant later. Understanding your body and menstrual cycle can help you identify problems long before you’re ready to have children. So whether you want to avoid getting pregnant now, are actively trying to conceive or simply want to improve your wellbeing, paying attention to your reproductive health is never wasted as it is inherently linked to general health throughout life.
Impact of the oral contraceptive pill on your periods
The oral contraceptive pills (OCP – “the pill”) is mainly used to prevent pregnancy but can also be prescribed to reduce menstrual symptoms. There are three types of oral contraceptive pills: combined oestrogen and progesterone, progesterone only and the continuous use pill. The most commonly prescribed pill is the combined hormonal pill with oestrogen and progesterone. Progesterone is the hormone that prevents pregnancy and oestrogen helps to control menstrual bleeding. The bleeding you experience on the pill is not a true period and is actually a withdrawal bleed caused by the withdrawal of the hormones you are taking when/if you take a break from the medication every month.
The pill is often prescribed to women with PCOS to improve menstrual and other symptoms, sometimes in conjunction with metformin, although a recent study found that, although this combination reduced hirsutism (excess facial or bodily hair), it wasn’t effective in improving the regularity of the menstrual cycle or weight loss. Other studies have found the pill did improve frequency of the menstrual cycle slightly and reduced acne in women with PCOS, so whether or not you experience benefit is likely to be individual to you and will also depend on the particular pill you are taking. Pills containing higher oestrogen levels can worsen cardiometabolic risk factors including BMI, lipids, blood pressure and glucose metabolism, however, and so be careful to monitor how you respond to any medication as further research is needed. Using diet and lifestyle as a starting point in managing symptoms is recommended.
Although many women tolerate the pill well, it can also bring side-effects including breast tenderness, headaches and mood changes. It can also very rarely cause blood clots but the risk is extremely low. If you have a history of breast cancer in your family, you should not take oestrogen-containing pills indefinitely and only use the pill during your teens and/ or early twenties when preventing a pregnancy is essential and use other forms of contraception thereafter. This is because if you have a genetic predisposition to breast cancer, oestrogen exposure can increase your risk further. Starting your periods young and having your first child late both increase your oestrogen exposure, so understanding your personal risk factors is important, especially if you have a family history. Excess alcohol also increases your risk of breast cancer.
It’s also important to note that the pill has been associated with reduced levels of several nutrients including Vitamins A, B1, B2, B6, B12, C, and E, folate, magnesium, zinc, selenium, and co-enzyme Q10. This means that you may notice problems if you stop taking the pill as you take away the benefit of improvements to your symptoms and are left with potentially low levels of nutrients needed for reproductive and menstrual health. Anything that contains or raises oestrogen in the body increases the absorption and retention of copper in the body, for instance. This includes pregnancy, oral contraceptives and being overweight, as fat tissue is metabolically active and produces different hormones, including oestrogen. High copper levels can inhibit zinc absorption (and vice versa). Given that zinc is needed for egg development, ovulation, hormone balance and many reproductive processes, you can start to see why problems with periods are common among women who have recently stopped taking the pill.
If you are trying to conceive, it’s helpful to come off the pill at least three months before you start trying if possible, as this will give your body time to rebalance ready for pregnancy. You may also benefit from nutrient testing and supplements to improve nutrient levels.
Menopause – when your periods stop
The menopause – when your periods stop altogether – happens when the store of eggs in your ovaries has been lost and it is no longer possible to get pregnant. This brings with it the loss of normal oestrogen levels that are present during your fertile years, which is associated with a host of challenging symptoms including hot flushes, reduced libido, acne, vaginal dryness and oily skin. It also brings an increased risk of numerous conditions including cardiovascular disease and osteoporosis, as oestrogen has a mainly protective effect on women’s health. Hormone replacement therapy (HRT) can provide significant relief from symptoms and you should discuss treatment options with your doctor, though this may not be suitable if you have a history of breast cancer in your family.
Perimenopause is the time immediately before the full menopause happens and the decline in oestrogen starts to bring about symptoms and changes in the body before your periods fully stop. Changes in hormones also affect the brain, with both pregnancy and perimenopause altering brain function leading to an increased risk of brain fog, forgetfulness and anxiety. The loss of oestrogen at menopause starts the changes in the brain that put women at increased risk of Alzheimer’s compared to men, so this occurs much earlier in life than previously recognised. Knowledge is, however, power as dietary and lifestyle factors make up a big proportion of your risk of developing this disease and affect mental health and cognition generally. So, whilst no supplements, or dietary and lifestyle changes can make up for the loss of oestrogen, taking positive action will help protect your brain now and as you age, and provide some alleviation of symptoms.
- Adam Balen and Grace Dugdale. The Fertility Book: Your Definitive Guide to Achieving a Healthy Pregnancy. Penguin Random House (Vermilion) 2021
- Euling SY, Selevan SG, Pescovitz OH, Skakkebaek NE. Role of environmental factors in the timing of puberty. Pediatrics. 2008 Feb;121 Suppl 3:S167-71. doi: 10.1542/peds.2007-1813C. PMID: 18245510.
- Oskar S, Wolff MS, Teitelbaum SL, Stingone JA. Identifying environmental exposure profiles associated with timing of menarche: A two-step machine learning approach to examine multiple environmental exposures. Environ Res. 2021 Apr;195:110524. doi: 10.1016/j.envres.2020.110524. Epub 2020 Nov 26. PMID: 33249040
- Barros BS, Kuschnir MCMC, Bloch KV, Silva TLND. ERICA: age at menarche and its association with nutritional status. J Pediatr (Rio J). 2019 Jan-Feb;95(1):106-111. doi: 10.1016/j.jped.2017.12.004. Epub 2018 Jan 18. PMID: 29352861.
- Velimir Matkovic, Jasminka Z. Ilich, Mario Skugor, Nancy E. Badenhop, Prem Goel, Albert Clairmont, Dino Klisovic, Ramzi W. Nahhas, John D. Landoll, Leptin Is Inversely Related to Age at Menarche in Human Females, The Journal of Clinical Endocrinology & Metabolism, Volume 82, Issue 10, 1 October 1997, Pages 3239–3245
- Al Khalifah RA, Florez ID, Dennis B, Thabane L, Bassilious E. Metformin or Oral Contraceptives for Adolescents With Polycystic Ovarian Syndrome: A Meta-analysis. Pediatrics. 2016 May;137(5):e20154089. doi: 10.1542/peds.2015-4089. PMID: 27244814.
- Michael P. Wakeman A Review of the Effects of Oral Contraceptives on Nutrient Status, with Especial Consideration to Folate in UK. Journal of Advances in Medicine and Medical Research, Pages 1-17
- Mosconi, L., Berti, V., Dyke, J. et al. Menopause impacts human brain structure, connectivity, energy metabolism, and amyloid-beta deposition. Sci Rep 11, 10867 (2021).
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