Your cycle can provide clues to your general health. Here are 15 possible causes for irregular menstruation.
Aregular menstrual cycle is a sign of good health so it’s a good idea to keep an eye on yours. Most menstruating women have a rough idea when their next period is due. A lucky few have a cycle that is as regular as clockwork. But what if your menstrual cycle is all over the place? Irregular periods can be normal but they can also have important underlying causes and indicate that something is amiss.
Dr Juliet McGrattan shares 15 reasons why your period might be irregular so you know when to relax and when to visit your doctor:
1.Irregular periods for no reason
Irregular periods can be completely normal. The average length of a menstrual cycle is 28 days but very few women bleed every four weeks on the dot. Anything from 21 to 40 days is classed as normal. If you have a three week cycle followed by a five week one then your periods may appear to be irregular. There’s no need to worry.
- Irregular periods during puberty
The menarche is the medical term used for when a girl first starts her periods. The menstrual cycle is partly driven by the release of an egg from one of the ovaries (ovulation). If the egg is not fertilised by a sperm, the lining of the womb comes away and a period begins. However, in the first year after the menarche, cycles may not be linked to ovulation. These are called anovulatory cycles and they’re often irregular. There may be short or long gaps between bleeds. Irregular periods in young teen girls are common. Over time they will usually settle down into a regular pattern as ovulation is established.
- Irregular periods and the peri-menopause
Anovulatory cycles, when periods happen without ovulation, are common at the extremes of our reproductive life so they’re more likely around puberty and during the peri-menopause in the lead up to the menopause. Between the age of 45 and 55, women may notice that their cycle becomes irregular. They may miss periods or have more frequent ones. Sometimes the bleeding can be heavier than usual. The gaps between periods will gradually get longer until periods cease altogether. When 12 months have passed since the last period then the woman has reached the menopause.
- Irregular periods after pregnancy
Periods usually stop completely during pregnancy. A small number of women have irregular bleeding in early pregnancy so it’s a good idea to take a pregnancy test if your periods are irregular and you might be pregnant. After pregnancy it can take several months before your ovaries fire back up and begin ovulating again so irregular periods are to be expected. You can fall pregnant again as soon as your ovaries release an egg and this may happen before your first period.
Irregular periods after a miscarriage are common; normal service has usually resumed within six months. Irregular periods after a termination of pregnancy (abortion) can also occur. Vaginal bleeding after a miscarriage or termination has usually settled by three weeks. You should speak to your doctor if it hasn’t or if the bleeding becomes smelly or discoloured.
- Irregular periods and breastfeeding
If you are exclusively breastfeeding your baby, giving all your baby’s milk from the breast, including night feeds, then you will probably not ovulate or have any periods. This is called being amenorrhoeic and is nature’s way of spacing out births because you are unlikely to become pregnant. Once baby starts weaning onto solid foods or you decide to stop breastfeeding, feeds become shorter and more spaced out. This will trigger your periods to restart but they may be irregular initially. Your usual pattern will resume within several months.
- Irregular periods and hormonal contraception
Whichever method of contraception you use, it’s not unusual to get some irregular bleeding when you first start it. This should settle down after two to three months for most women. Certain methods however have a higher risk of continued irregular bleeding. These are contraceptives that contain only progesterone and include the contraceptive injection, implant, progesterone only pill and intra-uterine systems (IUS – a type of coil). Bleeding does not mean the method is not working. It may settle over time but if the bleeding is problematic then speak to your family planning nurse or doctor. Contraceptives that contain a mixture of oestrogen and progesterone usually give better control of periods but irregular bleeding can still occur and should always be checked by a doctor.
- Irregular periods due to stress
Being stressed upsets the hormonal balance in your body and this can result in missed or irregular periods. It’s not unusual for example, to miss your period when you go on holiday, sit an exam or have extreme stress due to a bereavement or job loss. The mechanism isn’t fully understood but the high levels of the stress hormone cortisol interfere with the balance of the female hormones which control ovulation and menstruation. Cycles usually return to being regular once the stress has eased. It’s important to learn how to deal with stress and regularly take part in activities that help you relax such as seeing friends, exercise and meditation.
- Irregular periods due to weight changes
Being overweight or obese puts you at higher risk of irregular bleeding. If you gain weight rapidly you may find that your periods are impacted. Similarly, if you lose weight very quickly, which often happens during times of extreme stress or with an eating disorder, then your periods can become irregular. In this situation it’s common for them to be less frequent or even stop altogether. The body is reserving the reduced calories that you are consuming for essential purposes and reproductive functions get switched off.
- Irregular periods due to extreme exercise
Exercising frequently at an intense level uses lots of your body’s energy. If you are not taking in enough calories to fuel this exercise, your body ends up in a negative energy balance. It prioritises essential body functions and periods reduce and stop. If they stop altogether and you haven’t had a period for six months this is called amenorrhoea. It can have widespread effects on the body including reducing bone strength and increasing the risk of osteoporosis so it is important to see your doctor. Periods will usually return when the exercise intensity is reduced and calorie intake increased.
- Irregular periods and polycystic ovary syndrome
Polycystic ovary syndrome (PCOS) affects around one in 10 women in the UK and is a common cause of irregular periods. To be diagnosed with PCOS you have to have two out of three criteria:
- Irregular or absent periods.
- Multiple enlarged follicles seen on the ovaries during a scan.
- Either blood tests that show you have high levels of male hormones in your body or signs that indicate it, such as excess hair growth, acne or male pattern balding.
So, if you have irregular periods and facial hair then you might have PCOS. See your doctor if you think this is the case so you can be diagnosed and treated. PCOS can make it more difficult to get pregnant and women often worry about irregular periods and conception. Your doctor can refer you to a specialist if you have PCOS, irregular periods and want to get pregnant.
- Irregular periods and thyroid problems
The thyroid gland sits in the neck and controls our metabolism. If it becomes overactive (hyperthyroid) or underactive (hypothyroid) it can affect the menstrual cycle. Periods can become irregular, heavier or lighter. Every woman is different but in general, hyperthyroidism is more likely to lead to absent or fewer periods and hypothyroidism to irregular and heavier periods. Receiving treatment for the thyroid condition will usually restore a normal cycle.
- Irregular periods and endometriosis
The endometrium is the lining of the uterus (womb). Sometimes patches of the endometrium grow elsewhere in the body such as along the fallopian tubes, on the ovaries or on the bowel. Women who have endometriosis frequently experience irregular periods and stomach cramps. Bleeding is often heavy and painful. Other symptoms include pain from the bowel, uncomfortable sex and problems getting pregnant. There is no cure for endometriosis but symptoms can be reduced with treatment.
- Irregular periods and fibroids
Fibroids are tumours made of muscle that grow in or on the uterus. They are benign (non-cancerous). Fibroids can make period bleeding heavier and longer than usual. Bleeding in between periods is common and this may be heavy enough to confuse with a normal period making the cycle seem irregular. Fibroids are common during pregnancy and they usually shrink after the menopause. Troublesome and large fibroids can be treated with medication or surgery.
- Irregular periods due to ovarian cysts
Ovarian cysts are fluid-filled sacs that grow within or on the ovary. There are many different types but most are common, harmless and go away on their own. Ovarian cysts can cause a number of symptoms including upsetting your menstrual cycle making periods irregular and either more or less frequent. Other symptoms include bloating, abdominal pain and constipation. Cysts are usually initially assessed by an ultrasound scan and then further tests done if required.
- Irregular periods and cancer
Irregular periods are rarely caused by cancer. This should not be the first thing you think of when your periods become erratic; other causes are much more common. Sometimes cancer of the cervix (cervical cancer), cancer of the endometrium (endometrial cancer) or cancer of the ovary (ovarian cancer) can upset your regular bleeding pattern. Most often this will be bleeding between periods, an irregular cycle or heavier periods. See your doctor if you are concerned.
Tracking your menstrual cycle
Keeping an eye on your menstrual cycle not only allows you to work out when bleeding might begin but it’s also a good marker of your health. If it’s going haywire you can take steps to work out what the cause is. It might simply be a case of trying to reduce your stress or manage your food intake but it might be the sign of an underlying medical condition.
You can simply circle the days you bleed on a calendar or in a diary to track your cycle. There are also lots of period tracking apps designed for monitoring your cycle including those embedded into the health features on phones, sports watches and fitness trackers.
When to see your doctor about periods
Irregular periods may be entirely normal and nothing to worry about but you should make an appointment with your doctor if any of the following apply:
- Your periods are making day-to-day life difficult.
- You have bleeding in between your periods.
- Your periods are irregular and you are struggling to get pregnant.
- Your periods are normally regular and have suddenly changed to become irregular (and you are under 45 years old).
- You are having very frequent or very spaced out periods.