If you are sexually active and have missed a period, you could be pregnant so do a pregnancy test!

When women first start having periods, it can take a few months to get into a regular pattern. This is because your body is adjusting to changes in hormone levels, so don’t worry if you don’t have a period every month at the early stages.

During the menopause, the level of oestrogen falls and ovulation becomes a bit erratic. As a result, the length of time between periods may become longer or shorter, blood flow might be lighter or heavier, and you may even miss periods.

Excess stress levels interfere with the control centres in the brain that regulate the production of hormones. Periods can stop altogether or be more painful. You may notice your cycle is shorter or longer.

Tissue on the inner lining of the womb (endometrium) is found within the muscle of the womb (myometrium). It is not clear why this happens, but can cause heavy, painful periods.

Tissue on the inner lining of the womb is found outside of the womb. This can cause pelvic pain, pain prior to and during your period, deep pain during sex, heavy periods, cramps when opening your bowels or passing urine, and fertility issues. It can increase the likelihood of having an ectopic pregnancy and some women may have difficulty getting pregnant. It can be difficult to diagnose as the symptoms are very similar to those of other conditions, even bowel problems.

In this condition, a group of problems occur together. There are three main problems:

• Infrequent or absent periods
• Increased testosterone levels (causing acne, oily skin, thick hair growth on the face, neck, chest and nipple area
• 12 or more cysts on the ovaries (found on an ultrasound scan)

These are benign growths of the uterus – they are NOT cancers. They can cause heavy periods and pain, including problems with urination if they press on the bladder.

Chlamydia can cause bleeding after sex and between periods. Gonorrhoea rarely causes abnormal bleeding patterns.

All forms of hormonal contraception and blood thinning medication have the potential to affect bleeding patterns.

These affect the ability of the body to form a blood clot and can cause heavy vaginal bleeding as well as bleeding between periods.

A cancer can develop in the labia, cervix, or womb and cause abnormal vaginal bleeding. Bleeding can occur during and after sex, or between periods. Bleeding can also be heavier or longer than normal. Any bleeding after the menopause requires urgent investigation.

This is implantation of the foetus outside the womb. This can result in abnormal bleeding patterns, lower abdominal pain of varying intensity and quality, and even collapse. Bleeding can be concealed and cause pain in the tip of the shoulder. It can be difficult to make the diagnosis so an ectopic pregnancy should always be considered if you are of reproductive age, sexually active and experience abnormal vaginal bleeding and/or abdominal pain.

This is infection within the pelvis above the level of the vagina. It can cause pain in the lower abdomen which can be mild to severe, deep pain during sex, bleeding during or after intercourse, bleeding between periods, abnormal vaginal discharge, painful or frequent urination, and fever.