Premenstrual syndrome (PMS) describes a range of physical and psychological symptoms that can occur in the two weeks before a woman has her period (also known as menstruation).While PMS symptoms are generally relatively mild and manageable, for some women they can be severe, to the point where they cause distress and disrupt normal activities.…
What are periods?
A period (also called menstruation) occurs as part of a woman's normal menstrual cycle.
During a period, the uterus sheds its lining (also called the endometrium) that developed during the previous menstrual cycle and this passes out through the vagina.
When do women get their period?
Girls generally begin having their periods between 8-16 years of age, as part of the changes that occur during puberty, with the average age of a girl having her first period being 12 years. Most women continue to have periods (except during pregnancy) until menopause occurs, usually sometime between their late 40s and early 50s.
An average menstrual cycle is 28 days, although it can vary from 21-35 days.
The menstrual cycle
The menstrual cycle is a monthly cycle of changes that the female body goes through to prepare for a potential pregnancy. Control of the menstrual cycle is complex, involving a number of organs (the uterus and ovaries), glands (the hypothalamus and pituitary gland in the brain) and various hormones. These hormones rise and fall throughout three phases of the menstrual cycle - the follicular phase, ovulation and the luteal phase.
The follicular phase of the menstrual cycle begins on the first day of the period. The hypothalamus causes the pituitary gland to release follicle-stimulating hormone (FSH). This causes the ovaries to produce follicles, which are immature eggs, and oestrogen. The oestrogen stimulates the uterus to begin thickening its lining in preparation for ovulation.
Around halfway through the cycle, about two weeks before the start of the next period, there are rising levels of luteinising hormone that causes the release of a mature egg (ovum) from one or two of the follicles in the ovaries. The egg travels down the fallopian tubes towards the uterus. For around 24 hours, it is able to be fertilised by sperm. If this happens, the fertilised egg then embeds itself in the lining of the uterus and a pregnancy begins.
After the egg is released, the follicle in the ovary develops what is called a corpus luteum. The corpus luteum then produces the hormones progesterone and oestrogen, which help to maintain the thickened lining of the uterus.
If the egg is not fertilised, around the 22nd day of the cycle, the corpus luteum begins to shut down and stops producing progesterone. This triggers the uterus to begin shedding its lining and begin the next menstrual cycle.
If the egg is fertilised, it produces hormones that help maintain the uterus and corpus luteum and so stop the menstrual cycle for the length of the pregnancy.
Variations in your cycle
For young women, it can take a number of years for their menstrual cycle to settle down into a regular pattern. Once your cycle is regular, it may vary sometimes by a few days for a range of reasons including illness, stress, changes in your lifestyle, your weight and what you eat. However, if your cycle changes significantly for more than a couple of months, becomes irregular or stops completely for six months, it may be a sign of an underlying health condition that needs investigating by your doctor.
To understand what is normal for you, it can be helpful to record when your period starts, how long it lasts, as well as when any concerning symptoms occur.
Before your period
Premenstrual syndrome (PMS) describes a range of physical and psychological symptoms that can occur in the two weeks before a woman has her period. Most women do experience some level of symptoms due to PMS, however, they generally improve within a day or so of a period starting.
During your period
Periods and menstrual flow vary considerably between different women, so there is no single description of a 'normal' period.
Women can manage their periods with a range of products including the following:
- Sanitary pads - these are designed to line your underwear and absorb menstrual flow. They are generally changed every few hours, and;
- Tampons, which are thin cylinders of absorbent material that are inserted into the vagina. They are recommended to be changed at least once every 6-8 hours, more frequently when menstrual flow is heavy.
A rare medical condition called toxic shock syndrome (TSS) can be associated with tampon use, particularly if tampons are left in for an extended period of time. While the causes of TSS are not completely understood, it is thought to be due to toxins produced by bacteria such as Staphylococcus aureus and Streptococcus pyogenes. Symptoms of TSS include fever, headaches, vomiting and diarrhoea and requires emergency medical treatment.
During a period, bleeding from the vagina usually lasts around 2-7 days and is usually heaviest in the first two days.
- Consists of blood, cells and mucus from the lining of the uterus (endometrium). Small pieces of the endometrium may be visible;
- May include some clots of blood;
- Can change in colour over a period. Often it is bright red initially and may become brown or black towards the end of a period. This is because flow later in the period is slower and has been exposed to more oxygen, and;
- May slow down or temporarily stop during the third or fourth day and then resume again.
The amount of menstrual flow varies considerably between women and can vary between cycles. Estimates suggest up to 80 millilitres is common, but for some women a heavier flow will be quite normal.
If the menstrual flow is so heavy that you need to change a pad or tampon more than once an hour, this is not considered normal and requires investigation with your doctor. Passing large clots of blood can also be a sign of problems.
Also, even if it is normal for you, if your flow is so heavy that it is causing you problems and distress, your doctor can advise on treatments that are available to help reduce it.
Period pain is common and many women will experience it at some time during their lives. It often affects younger women soon after their periods start and tends to lessen as women get older.
- Generally occurs on the first day of your period, although for some women it can last longer or start in the days before their period begins, and;
- Is usually relatively mild, so that it can be managed by applying warmth (such as a hot pack), or with mild pain medications such as paracetamol, naproxen or ibuprofen.
Pain that is so severe that you need to take time off work, or take pain medications regularly, or that wakes you up at night is not considered normal and may need investigation with your doctor.
Women can be more likely to experience headaches or migraines around the time of their periods. If you suffer headaches or migraines that aren't able to be well managed by mild pain medications, other treatments are available. Your doctor can advise what options may be most suitable for you.
Bleeding between periods
It can take a number of years for some young women to establish a regular cycle and bleeding pattern. Some young women will spot slightly (pass a small amount of blood) during ovulation, about 14 days before their period.
Additionally, it can be normal for some women to:
- Spot slightly in the days just before their period, or;
- Bleed between periods when taking contraceptives or hormonal treatments.
Otherwise, bleeding between periods or after sex can be an indication of infection or other medical conditions, particularly if such bleeding is not usual for you. In rare cases, cancer can cause bleeding between periods, so it is important that it is investigated by your doctor.
After menopause, any bleeding may also be a sign of an underlying medical condition and needs to be checked by a doctor.
Seeing your doctor
If you have any concerns regarding your period and whether it is normal or not, you can always see your doctor or gynaecologist.
They will ask you about your symptoms and may recommend tests, which may include:
- A pelvic examination;
- Blood tests to check your blood count, iron levels, hormone levels and levels of important nutrients such as vitamin B12 and folic acid;
- A pelvic ultrasound;
- A hysteroscopy, and;
- Dilatation and curettage (D&C).
- About Periods | The Royal Womens Hospital. Accessed August 28 2014. link here Random House. The Womens Health Book. Random House Australia 2014.
- Heavy Periods (menorrhagia) - NHS Choices. Accessed August 28 2014. link here
- Menstrual Cycle | Better Health Channel. Accessed August 28 2014. link here
- Periods - Symptoms - NHS Choices. Accessed August 28 2014. link here
- Problem Periods | The Royal Womens Hospital. Accessed August 28 2014. link here
- Toxic Shock Syndrome | Better Health Channel. Accessed August 28 2014. link here
FAQ Frequently asked questions
What is a period?
A period (also called menstruation) is part of a woman's normal menstrual cycle. An average menstrual cycle is 28 days, although it can vary from 21 to 35 days. During a period, the uterus sheds its lining (which contains cells, blood and mucous) and this passes out …
What is a menstrual cycle?
A menstrual cycle is the regular cycle of changes that prepares a woman's reproductive system for pregnancy. It involves a complex system of glands, hormones, and the uterus and ovaries. An average menstrual cycle is 28 days, although it can vary from 21 to 35 …
At what age do women have periods?
Girls generally start having periods between the ages of 8 and 16, with the average age being 12 years. Except during pregnancy, most women will continue to have periods until menopause, which generally occurs in their late 40s to early 50s.
How much blood is it normal for women to lose during their period?
Menstrual flow varies between women, but it is common for it to be up to 80 millilitres. If you have to change your tampon or sanitary pad more than once an hour, this can indicate very high flow that needs to be …
Is it normal to bleed between periods?
It can take a few years for some young women to establish a regular cycle and bleeding pattern. Some young women will spot slightly (pass a small amount of blood) during ovulation, about 14 days before their period. Additionally, it can be normal for …
Are blood clots normal during a period?
Women can pass small blood clots during a period. If you begin to pass a number of large blood clots, this may be a sign of problems that require investigation by a doctor.
Is it normal for menstrual flow to stop during a period and start again?
It is not unusual for menstrual flow to stop temporarily on the third or fourth day of a period and then begin again.
Is it normal for my period to stop?
If you've had regular periods and then your periods stop occurring for six months or more, this may indicate underlying health conditions that require investigation by a doctor.
What is period pain?
Period pain is caused by prostaglandins (hormones released during the menstrual cycle) that cause the muscle layer of the uterus to cramp or contract. As well as pain in the lower abdomen, women can experience back pain. Period pain generally occurs on the first day of …