Usually, a period cycle lasts for somewhere between four and seven days. While it's typical for menstrual periods to occur every 28 days, normal menstrual cycles can range anywhere from 21 to 35 days. Moreover, many women also experience various menstrual problems including missing periods, a period cycle of more than 35 days or less than 21 days, or a menstrual flow that is much lighter or heavier than usual. While it's normal to have irregular periods on occasion, it's still a good idea to consult with a gynaecologist about it just in case there is a serious underlying issue. 

While there can be a myriad of reasons behind irregular periods, some of the most common ones include:

1. Stress and Lifestyle Factors

When you are stressed, your body produces and releases stress hormones like cortisol and adrenaline. These hormones interfere with the functioning of sex hormones, which are responsible for regulating menstruation. In addition to experiencing chronic stress, other lifestyle factors that can impact the regularity of your menstrual cycle include dieting, sudden weight gain or loss, change in exercise routine, acute illness, frequent travelling, and other disruptions in the daily routine. 

2. Birth Control Pills

The majority of birth control pills are a combination of progestin and oestrogen hormones, which regulate your periods. Going off or on birth control pills can affect your menstruation. Moreover, some women experience missed or irregular periods for up to six months after discontinuing the pills. In addition to these pills, other birth control methods like implants, IUDs, and rings can also cause irregular periods. 

3. Polycystic Ovary Syndrome (PCOS)

The ovaries of women suffering from polycystic ovary syndrome produce an abundance of male hormones called androgens, resulting in the formation of small fluid-filled cysts in ovaries. This hormonal imbalance can prevent the maturation of eggs, thereby restricting consistent ovulation (the process involving the release of a matured egg from the ovary). This can make a woman miss her periods or have irregular cycles. 

4. Breastfeeding

A hormone, called prolactin, is responsible for breast milk production. This hormone can also hamper ovulation, especially in women who frequently and exclusively breastfeed during their baby's initial months. Referred to as lactational amenorrhea, the breastfeeding mother would not get periods during this phase. This menstrual irregularity isn't harmful and reversible once breastfeeding stops. 

5. Thyroid Issues

The butterfly-shaped thyroid gland in the neck produces thyroid hormones, which affect women's menstrual cycles. Those with an underactive thyroid, also known as hypothyroidism, do not produce enough hormones, causing heavier menstrual flow and longer period cycles. On the other hand, those with an overactive thyroid gland, also called hyperthyroidism, can have lighter menstrual flow along with shorter periods. 

6. Uterine fibroids

Fibroids refer to growths that can form on the walls of your uterus. While mostly non-cancerous, their size can range from anywhere as small as an apple seed to as large as a grapefruit. A woman with uterine fibroids can experience extremely painful periods with a flow that may result in anaemia. Moreover, if these fibroids are big, they can put pressure on the rectum or bladder, resulting in discomfort. 

In addition to the causes mentioned above, several other problems such as endometriosis, pelvic inflammatory disease, premature ovarian insufficiency, certain medicines, and complications related to pregnancy can result in missed or irregular periods. If you deal with any such problem, it is wise to consult an expert for further investigation and an apt treatment plan. If you are dealing with irregular periods and need expert advice,

Consult An Apollo Gynaecologist

Medically reviewed by Dr Sonia Bhatt.