Delayed menstruation: Reasons and signs of needing medical attention
Irregular periods—defined as cycles that are unpredictable, unusually long, short, heavy, or light—are a common concern, and while pregnancy is a well-known cause, many other factors can disrupt menstrual regularity. Here, we explore the various causes of irregular periods, including hormonal imbalances, lifestyle and environmental factors, medical conditions, and medications.
Hormonal Imbalances --------------------
Polycystic Ovary Syndrome (PCOS) is a leading cause of irregular or absent periods due to hormonal imbalances that prevent regular ovulation. PCOS affects approximately 1 in 10 women of reproductive age and is characterised by high levels of insulin, low levels of sex hormones, and the formation of multiple cysts on the ovaries[1][2][4].
Thyroid disorders, both hypothyroidism and hyperthyroidism, can also disrupt the menstrual cycle by altering hormone levels. People with low levels of thyroid hormone tend to experience more frequent bleeding, while those with high levels of thyroid hormone may experience irregular periods or amenorrhea[1][2][4].
Prolactin imbalances, such as hyperprolactinemia, can cause amenorrhea, discharge from the nipples, and low bone mass. Prolactin is the hormone responsible for milk production[1].
Perimenopause and adolescence are also known to cause irregular cycles due to hormonal fluctuations. Hormonal fluctuations during puberty and the years leading up to menopause often cause irregular cycles[2]. Other hormonal issues, such as dysfunctional uterine bleeding (DUB), often linked to estrogen and progesterone imbalances, are common causes, especially in teenagers and perimenopausal women[2].
Lifestyle and Environmental Factors -------------------------------------
Stress, whether physical or emotional, can disrupt the hypothalamic-pituitary-ovarian axis, leading to delayed, skipped, or irregular periods[1][3][4]. Intense physical activity, especially when combined with low body weight, can lead to menstrual irregularities or amenorrhea (absent periods)[3]. Significant weight loss or gain, including eating disorders like anorexia and bulimia, impact hormone production and can cause irregular cycles[3][4].
Travel and sleep disruption can temporarily disrupt menstrual regularity[4]. Changes in routine, such as travel across time zones or irregular sleep patterns, can impact hormone levels and cause irregular cycles.
Medical Conditions and Medications -----------------------------------
Uterine fibroids and polyps can cause heavy, prolonged, or irregular bleeding[2]. Endometrial hyperplasia and adenomyosis, abnormal thickening of the uterine lining or endometrial tissue growing into the uterine muscle, can cause irregular bleeding[2]. Pelvic infections, such as cervicitis or endometritis, may lead to abnormal bleeding patterns[2]. Conditions affecting blood clotting can result in unusually heavy or prolonged periods[2].
Though less common, cancers of the cervix, uterus, vagina, or endometrium can cause irregular bleeding[2].
Contraceptives and Medications -------------------------------
Hormonal contraceptives, such as birth control pills, patches, rings, shots, and hormonal IUDs, often cause lighter, shorter, or skipped periods[1][3][4]. Discontinuing hormonal birth control can temporarily result in irregular cycles as the body readjusts[1][3]. Certain medications, including some antipsychotics and chemotherapy drugs, may also affect menstrual cycles.
When to Seek Medical Advice ----------------------------
While occasional irregularity is normal, it is essential to consult a healthcare provider if you experience:
* Periods more frequent than every 21 days or less frequent than every 35 days * Bleeding that lasts longer than 7 days * Bleeding after menopause * Severe pain or unusually heavy bleeding * Periods that stop for several months without explanation
Summary Table of Common Causes --------------------------------
| Cause Type | Examples | |---------------------------|-----------------------------------------------| | Hormonal Imbalances | PCOS, thyroid disorders, prolactin issues | | Lifestyle Factors | Stress, excessive exercise, weight changes | | Medical Conditions | Fibroids, polyps, infections, cancer | | Contraceptives/Medications| Hormonal birth control, medication changes |
Irregular periods can stem from a wide range of factors beyond pregnancy, including hormonal imbalances, lifestyle influences, underlying medical conditions, and contraceptive use[1][2][3]. Persistent or concerning changes warrant evaluation by a healthcare professional.
- PCOS, a common hormonal imbalance in women, causes irregular periods due to high insulin levels, low sex hormones, and the formation of multiple cysts on the ovaries.
- Thyroid disorders, whether hypothyroidism or hyperthyroidism, can disrupt the menstrual cycle by altering hormone levels, leading to frequent bleeding or irregular periods.
- Prolactin imbalances can cause amenorrhea, discharge from the nipples, and low bone mass, as prolactin is responsible for milk production.
- Irregular cycles during perimenopause and adolescence are due to hormonal fluctuations common during these stages.
- Stress and intense physical activity, especially when combined with low body weight, can lead to menstrual irregularities or amenorrhea.
- Significant weight loss or gain, including eating disorders like anorexia and bulimia, impact hormone production and can cause irregular cycles.
- Certain medical conditions, such as uterine fibroids, endometrial hyperplasia, adenomyosis, pelvic infections, and blood clotting disorders, can result in irregular bleeding patterns.
