Cycle means circle and indicating that it is the same hormone pattern that repeats itself in each cycle. The woman's cycle starts the day she gets her period. This means that it is day 1 of the cycle. Menstruation usually lasts 3-7 days and the woman’s cycle runs until she gets menstruation again and the cycle starts all over again. So, the time from the first day of menstruation until the day before she gets the next menstruation is the number of days that the cycle in question lasted.

On average, the woman's cycle lasts 28-29 days, but it is quite normal for the cycle to vary from 23-35 days. As women approach menopause, there may be longer and longer periods between menstrual periods, and it is therefore normal for the cycle to become longer, and the woman experiences that she begins to skip menstruation. Try our FSH Menopause test here: Femometer FSH Klimakterietest – Gravidtid

After the woman's menstruation is over, a new egg develops in the woman's ovaries and the body produces estrogen, which causes the uterine lining to grow. Ovulation occurs in the middle of a woman's cycle about 14 days before her next period. That is, on day 14 at a cycle of 28 days or on day 18 at a cycle of 32 days. Read more about ovulation here:What is ovulation and when is the greatest chance to get pregnant? – Gravidtid  

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Regular cycle

A woman has regular menstrual periods if there is a roughly equal time between her menstrual periods and the bleeding lasts for approximately the same duration. So, her cycle is almost the same length every month. In 20-year-old women, it lasts an average of 30 days, while in 40-year-old women it is usually 26 days. In every fifth woman, within a year there will be a bleeding that does not suit her cycle pattern, which is completely normal and not an expression of problems. Most often it will be due to temporary hormonal disorders, stress, weight gain, weight loss, excessive exercise, or the like, which you can help to influence. If you as a woman want a pregnancy, it is automatically easier to plan an attempt at pregnancy if the woman's cycle, and thus her ovulation, is regular: What is a menstrual cycle and when is the cycle regular or irregular? – Gravidtid

Irregular cycle

You have irregular periods if there is a difference of several days in the length of time between the woman's periods and the difference in how long her bleeding lasts. The irregular bleeding is most often due to hormonal disorders in the hormones that are formed in connection with ovulation. This may mean that the lining of the uterus does not grow regularly and is thickened.

The most common explanation for why a woman has irregular periods is PCOS (polycystic ovary syndrome. Read more about it here:What is PCOS? Symptoms and what you can do if you want to get pregnant – Gravidtid) , sexually transmitted diseases such as chlamydia, stress, menopause, lack of ovulation and contraception. You should consult a doctor if the cycle is shorter than 21 days or longer than 35 days or if spotting begins without explanation. The same applies if the menstruation suddenly becomes significantly heavier than normal or you start bleeding after intercourse. 

 Source:, HerlevHospital,