arrow-small-left Created with Sketch. arrow-small-right Created with Sketch. Carat Left arrow Created with Sketch. check Created with Sketch. circle carat down circle-down Created with Sketch. circle-up Created with Sketch. clock Created with Sketch. difficulty Created with Sketch. download Created with Sketch. email email Created with Sketch. facebook logo-facebook Created with Sketch. logo-instagram Created with Sketch. logo-linkedin Created with Sketch. linkround Created with Sketch. minus plus preptime Created with Sketch. print Created with Sketch. Created with Sketch. logo-soundcloud Created with Sketch. twitter logo-twitter Created with Sketch. logo-youtube Created with Sketch.

Is your period regular?

How long your period lasts and how heavy it is varies for each woman. Here you can find information on irregular and absent periods, as well as ways to help get your periods regular if you need to.

Topics on this page

Most women will menstruate for around 40 years, and can expect to have about 500 period cycles during their lifetime.

Period-related problems are a common reason for time off work or, school, or for visits to the doctor, and may have a significant impact on a woman's quality of life. Periods can cause issues at any age, but they more commonly affect teenagers and those approaching menopause.

Is your period normal?

The menstrual cycle is a normal part of every woman's life. How long it lasts, how heavy it is and the time between periods varies for each woman. It can be bright red, dark red or dark brown in colour, and may contain small clots (dark pieces of blood). Clots that are greater than a 50 cent piece in size should be investigated further by your doctor. On average, women lose about 20-80ml of blood during each period (20ml being equal to four teaspoons and 80ml equal to one-third of a cup).

In the first 2-3 years after a girl's period has started, periods can be irregular, as it can take a year or two for the cycle to regulate. Once regular, periods tend to begin around the same time each month (on average every 26-29 days), but can be as often as three weeks apart or as far apart as eight weeks. You can still be ovulating either regularly or irregularly right up until your period stops at menopause.

Common regularity issues

Irregular periods – oligomenorrhoea

Periods may be irregular in the lead-up to menopause, following childbirth, miscarriage or termination of a pregnancy or, as already mentioned, in the first few years after they begin. However, some women never establish a regular cycle. Irregular periods can be due to:

  • change in diet – reducing intake
  • sudden weight loss or gain
  • polycystic ovary syndrome (PCOS) – a hormone disorder
  • pregnancy, miscarriage or an ectopic pregnancy (when a pregnancy occurs in the fallopian tube or somewhere outside the uterus)
  • changing or starting contraception (oral or long-acting)
  • stress.

Absence of periods – amenorrhoea

Absence of periods (other than in pregnancy) may occur because of a hormonal disturbance caused by factors including weight gain or loss, over-exercising, anxiety or stress, travel, dietary changes and conditions such as PCOS, or pituitary or thyroid disease. Amenorrhoea can be temporary, with periods returning after some months. Women experiencing amenorrhoea for longer than six months are advised to consult a doctor.

Heavy menstrual bleeding

A heavy period (more than 80ml) can significantly interfere with everyday life. While it is difficult to accurately measure the amount of menstrual fluid, having to change your pad or tampon hourly, needing to change during the night, or having to get thicker pads or larger tampons to contain the blood flow is a good guide that your period is heavy.

A number of factors – including fibroids, polyps, endometriosis, adenomyosis and, rarely, uterine cancer – can cause heavy bleeding. Heavy bleeding may then lead to anaemia (low haemoglobin blood count) and iron deficiency, with symptoms of fatigue, paleness, lack of energy and shortness of breath.

When no cause is found, medications to reduce bleeding are usually prescribed. These include a non-hormonal medication, transexamic acid, the oral contraceptive pill and progestin hormone therapies including tablets or a progestin hormone-releasing intra-uterine device (IUD).

Spot bleeding between periods

Bleeding between periods can be caused by diet, stress, being underweight, doing too much exercise, sexually transmissible infections (STIs), endometriosis, fibroids, endometrial polyps, PCOS, thyroid disorders, cervical polyps or gynaecological cancer. It can also be a side effect of some contraceptives or medications.

Any bleeding between periods must be investigated by a doctor, particularly for postmenopausal women who are at higher risk of endometrial cancer. "When you visit your doctor, it helps if you can describe your pattern of bleeding," says Jean Hailes gynaecologist and medical director Dr Elizabeth Farrell. "The doctor will also need to know if bleeding occurs after sex, or if there is any accompanying pelvic or lower abdominal pain."

Will the oral contraceptive pill (OCP) & other hormonal implants help regulate your period?

The OCP and vaginal contraceptive ring can help regulate periods, reduce menstrual cramps and reduce acne and excess hair growth, depending on the type. There are a wide range of OCPs with differing doses of oestrogen and progesterone. Other hormonal contraception devices prescribed, including hormonal implants, vaginal contraceptive ring and intra-uterine devices containing progesterone, will not necessarily regulate your cycle, but will for some women.

The contraceptive pill

How does hormonal contraception work?

The oestrogen and progesterone in hormonal contraception work by overriding the body's normal hormonal control of the menstrual cycle and ovulation. You can safely skip multiple periods while on the pill, but you need to make sure you don't miss taking any pills. Some women may experience spotting or breakthrough bleeding when taking the active pills continuously. Find more information on hormonal contraception including the OCP, implants, the vaginal contraceptive ring and IUD devices, here.

Other medications to improve period regularity

Insulin-sensitising drugs used mostly for diabetes (primarily metformin) can improve the regularity of periods and ovulation. Metformin does not appear to be quite as effective as the OCP in improving menstrual regularity. However, metformin has a more positive effect than the oral contraceptive pill on risk factors for cardiovascular disease and type 2 diabetes, such as cholesterol levels and insulin. This is used usually in women with PCOS.

When to see your doctor

It is important to see your doctor if you experience any issues with your period that worry you. Keeping a menstrual diary, including when you get your period, the length, heaviness and anything else you notice, will help your doctor work out how best to help you.

You should consult your doctor if you:

  • have not started menstruating by the age of 16-17
  • notice your period has suddenly stopped
  • are bleeding for more days than usual
  • are bleeding excessively, or more than you usually do
  • bleed between periods, or after sexual intercourse
  • experience pain during your period that interferes with your quality of life
  • have clots that are bigger than a 50-cent piece in size.

This web page is designed to be informative and educational. It is not intended to provide specific medical advice or replace advice from your health practitioner. The information above is based on current medical knowledge, evidence and practice as at July 2018.


  • 1
    Knox B, Azurah AG, Grover SR. Quality of life and menstruation in adolescents. Current opinion in Obstetrics & Gynaecology. 2015;27;309–14.
  • 2
    Greydanus D, Omar H, Tsitika A, Patel D. Menstrual disorders in adolescent females: current concepts. Disease A Month. 2009.
  • 3
    Siqqiqui N, Pitkin J. Menstrual disturbances. Obstetrics, Gynaecology and Reproductive Medicine. 2007;17:154–62.
  • 4
    Wang JG, Lobo RA. The complex relationship between hypothalamic amenorrhea and polycystic ovary syndrome. J Clin Endocrinol Metab. 2008;93:1394.
Last updated: 17 July 2020 | Last reviewed: 10 July 2018

Was this helpful?

Thank you for your feedback

Related Topics