A regular menstrual cycle typically occurs every 21 to 35 days and lasts between two and seven days, involving hormones that prepare the body for potential pregnancy. While a consistent pattern is common, many factors can cause periods to stop and then start again, signaling a temporary shift or an underlying health matter.
Temporary Hormonal Shifts and Lifestyle Factors
Psychological or physical stress can notably affect the hypothalamic-pituitary-ovarian (HPO) axis, a system that regulates reproductive hormones. Chronic stress can suppress the release of hormones essential for ovulation, potentially delaying or stopping a period, which may then resume once stress levels decrease.
Significant fluctuations in body weight, whether gain or loss, also influence hormone levels and can impact menstrual regularity. Adipose tissue, or body fat, produces estrogen, so both very low and very high body fat percentages can disrupt the balance of estrogen and progesterone necessary for a regular cycle. Intense physical activity or restrictive dieting can similarly reduce estrogen levels, leading to irregular or absent periods.
Natural life stages such as puberty and perimenopause are also characterized by hormonal shifts that can cause irregular bleeding. During puberty, a person’s cycles are often irregular as the reproductive system matures. Conversely, perimenopause, the transition leading to menopause, involves fluctuating hormone levels that can result in unpredictable periods before they eventually cease.
Hormonal birth control methods can also cause irregular bleeding patterns, particularly when starting, stopping, or changing methods. This phenomenon, known as breakthrough bleeding, is common in the first few months as the body adjusts to new hormone dosages. Missing doses of oral contraceptives can also trigger unexpected bleeding. Additionally, early pregnancy can sometimes cause light bleeding, known as implantation bleeding, which might be mistaken for a period but is typically lighter and shorter.
Medical Conditions Affecting Menstrual Patterns
Polycystic Ovary Syndrome (PCOS) is a common hormonal disorder where imbalances, including elevated androgens, interfere with ovulation. This anovulation can lead to irregular, infrequent, or absent periods, often punctuated by unpredictable bleeding.
Thyroid disorders, encompassing both an underactive (hypothyroidism) and overactive (hyperthyroidism) thyroid, influence the menstrual cycle. Thyroid hormones are integral to metabolism and reproductive function, and an imbalance can result in irregular, heavy, light, or absent periods. For instance, hypothyroidism can lead to more frequent or heavier periods, while hyperthyroidism may cause lighter or missed periods.
Structural issues within the uterus, such as uterine fibroids or polyps, can also cause irregular bleeding. Fibroids are non-cancerous growths of muscle tissue, and polyps are growths of the uterine lining, both of which can lead to heavy, prolonged, or intermittent bleeding between periods. Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, can cause painful and irregular bleeding, including spotting between periods. This occurs because the displaced tissue responds to hormonal fluctuations, leading to inflammation and bleeding.
Premature Ovarian Insufficiency (POI) occurs when the ovaries stop functioning normally before age 40, leading to reduced estrogen production and irregular periods, or even their complete cessation. While some individuals with POI may experience sporadic ovulation, irregular bleeding is a common symptom. Less common causes of irregular bleeding can include certain sexually transmitted infections (STIs) or other cervical issues, which may cause inflammation or irritation leading to spotting.
When to Consult a Healthcare Professional
Consult a healthcare professional if you experience sudden, significant changes in your cycle’s regularity or flow. This includes periods that become very irregular after having been consistent, or if bleeding occurs between periods.
Other concerning symptoms include very heavy bleeding, such as soaking through a pad or tampon every hour for several consecutive hours, or bleeding that lasts longer than seven days. Severe pain that accompanies irregular bleeding and is not relieved by over-the-counter medication also warrants medical attention. Additionally, any bleeding after menopause should be promptly evaluated by a doctor.
Consult a doctor if you have concerns about pregnancy or experience other symptoms suggestive of an underlying medical condition, such as excessive hair growth, unexplained weight changes, or persistent fatigue. This information is for general knowledge and does not substitute for personalized medical advice from a qualified healthcare provider.