Reasons for irregular periods
Written in association with:
Published: 14/11/2024
Edited by: Jessica Wise
Every menstrual cycle, just like every body, is different. They might differ in duration, in the length of time between periods, in how much blood is shed, what the accompanying symptoms are. Normally, the length of the cycle is between 21 to 42 days. The standard of an “irregular” period will be based on what is “normal” for each individual, as they are determined by age, weight, contraceptive methods, if there have been previous pregnancies, breastfeeding status, and proximity to menopause. This is because these factors affect hormone levels, which may disrupt “normal” periods. In this article, a consultant gynaecologist and laparoscopic surgeon goes over some of the reasons why a period may be irregular.
Periods tend to be irregular in the first few years and the last few years of menstruation, as the ovulation isn’t yet on consistent schedule. It is usually around the early 20s that the cycle is stabilised, and will remain so until as early as the mid-40s, though sometimes the cycle can persist even until the late 50s.
Causes of irregular periods
Late periods
A period that is a week late isn’t at all unusual and can happen to any menstruating person for a variety of reasons, such as stress, travelling, changes in hormones, diet, or sometimes without any clear reason. However, a period that is repeatedly late, or more than a week late, then it can be due to something a bit more significant, such as:
Pregnancy. If you have had sexual intercourse within the past six weeks, even with contraception, you may want to take a pregnancy test. Polycystic ovary syndrome. This a common condition where many small cysts form in the ovaries, obstructing ovulation and delaying menstruation. Hormonal imbalance. Issues with the ovaries, thyroid, or pituitary glands can cause major hormonal level imbalance, especially oestrogen and progesterone levels, which will disrupt menstruation. Eating disorders. Anorexia and bulimia can lower the body fat disproportionately due to the body not getting enough nutrients to produce the hormones that facilitate menstruation. The same can happen with overexercising. Medications. Drugs like aspirin, psychiatric medications, chemotherapy, and steroids can affect the period in many ways, altering the intensity of bleeding or halting them. Birth control and contraceptive treatments can also lighten the period or stop it entirely, or cause light spotting between periods.
Irregular periods after birth
After giving birth, the period should restart after six to eight weeks, but this can differ based on your breastfeeding habits. Those who are breastfeeding exclusively may not have their periods resume until they stop, but this is not guaranteed. This happens due to the production of the hormone prolactin, which is the producer of breastmilk and suppresses ovulation, as well as the energy demand of breastfeeding means that the body is prioritising milk production instead of reproductive function. Regardless, the breastfeeding period should not be relied upon as a form of birth control.
Periods that are long, heavy, or unusually painful after birth should be brought to the attention of your doctor.
Perimenopausal irregular periods
Perimenopause, or the transitory period before menopause, is when the body is preparing to stop the menstrual cycle for the rest of the individual’s life. At this time, the hormones levels, particularly those of oestrogen and progesterone, are in disarray and subsequently disrupt the menstruation in unpredictable ways, causing it to be longer, shorter, heavier or lighter. The perimenopause becomes menopause once menstruation has not occurred once over 12 consecutive months, though the hormone levels will still be in decline.
Irregular periods after miscarriage
A miscarriage can be highly traumatic psychologically as well as biologically. Periods are likely to be irregular for up to a few months after a miscarriage as the body recovers for the following reasons:
Hormones levels will need time to recalibrate and return to pre-pregnancy levels. The uterus needs time to rebuild its lining (endometrium) Some pregnancy tissues will have not been expelled entirely during the miscarriage and may obstruct ovulation. It may be necessary to have the tissue medically removed. The emotional impact of a miscarriage can cause a lot of stress. Infections or complications associated with the miscarriage can further affect the menstrual capabilities with hormonal imbalance or inflammation, for example. Any heavy bleeding, extreme pain, fever, and foul-smelling discharge should be brought to the attention of a doctor.
Irregular periods after stopping birth control
Most people find that their usual menstrual resumes soon after they have ceased taking the birth control pill, even after years of being on it; however, a portion of them may have a delay in ovulation a miss a few periods. This is due to the suppression on the pituitary gland caused by the pill needs a bit of time to lift before the menstruation cycle can return.
In any case, if you are missing periods after stopping the pill, consult with your doctor so they can confirm that there are no other issues or complications that is causing the irregularity.
How to treat irregular periods
If you notice that your periods have been irregular, keep track of them and the irregularities with a menstruation journal or any of the many apps built for this purpose.
Irregular periods may impact fertility, depending on the source of the irregularity. If you are struggling with conceiving, consult with your doctor so they may investigate.
A one- or two-off irregularity like a slightly early or slightly late period tends to be innocuous, but if it becomes a pattern of irregularity with strange timing, longer duration, heavier bleeding, or bleeding between periods and after sex, then that might be a cause for concern and you are recommended to see a doctor or gynaecologist.
If you are experiencing an irregular period and would like to consult with a specialist, you can do so on Top Doctors today.