It can be unsettling when your period is late, and pregnancy isn’t the reason. For individuals assigned female at birth (AFAB), menstruation is a regular part of life, typically occurring around every 28 days, though cycles can naturally vary from 21 to 45 days. Once your cycle establishes a pattern, deviations can be a cause for concern and often signal underlying factors.
If you’re experiencing a late period and know pregnancy isn’t the cause, you might be encountering amenorrhea, the medical term for the absence of menstruation. Amenorrhea itself isn’t a disease but rather a symptom indicating another condition. Understanding why your period is late, even if it’s just occasionally, is crucial. Consistent menstrual irregularities can have long-term health implications.
Here are seven common reasons for a late period when you’re not pregnant:
1. Age-Related Cycle Changes
Irregular periods are frequently observed at two distinct life stages: during the initial years after menstruation begins and as menopause approaches.
In the years following your first period (menarche), menstrual cycles can be erratic. It’s not uncommon for young individuals to experience irregular periods for up to six years as their bodies establish a consistent hormonal rhythm. However, once a regular pattern develops, menstrual cycles typically become predictable for the following decades, barring pregnancy.
As you approach menopause, usually between 45 and 55 years of age, your body transitions, leading to menstrual cycle changes, including late or missed periods. This transitional phase encompasses several stages:
- Perimenopause: This is the menopausal transition period, divided into early and late stages. The early stage is characterized by inconsistent periods. In the late stage of perimenopause, the interval between periods can extend beyond 60 days.
- Primary Ovarian Insufficiency (POI): Also known as premature ovarian failure, POI causes estrogen levels to decline, and the ovaries cease functioning before the age of 40. Affecting about 1% of individuals AFAB under 40, POI results in irregular or absent periods.
- Premature or Early Menopause: The average age for menopause is 52. Early menopause occurs between 40 and 45 years, affecting approximately 5% of individuals AFAB. Premature menopause is diagnosed when menopause occurs before age 40 and is not attributed to POI.
- Menopause: Menopause is confirmed when you’ve gone a full year without menstruation, are over 50, and other causes of amenorrhea are ruled out.
2. Stress and Lifestyle Factors
Stress significantly impacts bodily functions, influencing sleep patterns, dietary habits, and overall well-being. Notably, stress can also cause a delay in your menstrual period. Research indicates a direct correlation between perceived high stress levels and menstrual cycle irregularities in individuals aged 20 to 40.
Chronic stress can lead to hypothalamic amenorrhea, where periods cease entirely. When the body is under stress, it produces more cortisol, a hormone that can disrupt the hypothalamus, the brain region regulating menstruation. This disruption in hypothalamic function can halt menstruation.
Factors beyond just psychological stress can also contribute to late periods. Drastic changes in routine, travel across time zones, or significant shifts in sleep patterns can all disrupt your body’s natural hormonal balance and menstrual cycle. Even intense exercise can sometimes lead to missed or late periods, particularly if it’s coupled with inadequate calorie intake.
3. Polycystic Ovary Syndrome (PCOS)
Polycystic ovary syndrome (PCOS) is a hormonal disorder common among individuals AFAB. It’s characterized by elevated levels of androgens, often referred to as “male hormones.” This hormonal imbalance can disrupt the ovaries and lead to the formation of cysts – fluid-filled sacs – on the ovaries, which in turn can prevent ovulation.
Irregular or missed periods are a hallmark of PCOS. Beyond menstrual irregularities, PCOS often presents with other symptoms, including:
- Acne: Breakouts on the face, chest, and back.
- Skin Darkening (Acanthosis Nigricans): Dark patches of skin, especially in folds and creases.
- Excessive Hair Growth (Hirsutism): Increased hair growth on the face, chin, or chest.
- Skin Tags: Small, painless skin growths on the upper body and neck.
- Weight Issues: Weight gain or difficulty losing weight.
4. Weight Fluctuations
Body weight plays a crucial role in hormonal balance and menstrual regularity. Both extremes – being underweight or overweight – can disrupt your monthly cycles.
Low body weight or eating disorders can interfere with ovulation and cause irregular periods. Insufficient body fat or inadequate nutrient intake can hinder the body’s ability to produce the hormones necessary to regulate menstruation. Rapid weight loss can also lead to the complete cessation of periods.
Conversely, being overweight or obese can also affect menstruation. A high body mass index (BMI) and obesity can cause imbalances in estrogen and progesterone levels, disrupting the menstrual cycle. Furthermore, weight gain and obesity are linked to an increased risk of developing or worsening PCOS, further contributing to menstrual irregularities.
5. Birth Control Methods
Many types of birth control utilize hormones to prevent pregnancy by affecting ovulation. Starting, stopping, or switching birth control methods can significantly disrupt your menstrual cycle due to hormonal fluctuations. It may take up to three months or longer for your cycle to return to its regular pattern after such changes.
Certain contraceptives are designed to cause lighter or even missed periods throughout their use. These include:
- Birth Control Implants: These release hormones directly into the bloodstream.
- Hormonal Intrauterine Devices (IUDs): Hormonal IUDs primarily work by preventing fertilization and can also thin the uterine lining, leading to lighter or absent periods.
- Progestin-Only Pills (Mini-Pills): These pills, containing only progestin, may prevent ovulation in some individuals, resulting in lighter or missed periods.
If you have an IUD and experience complete absence of periods (amenorrhea), it’s essential to consult your healthcare provider to rule out rare complications, such as ectopic pregnancy, where the fertilized egg implants outside the uterus.
6. Thyroid Gland Disorders
The thyroid gland, located in the neck, produces hormones that regulate growth, development, and metabolism. Both an overactive thyroid (hyperthyroidism) and an underactive thyroid (hypothyroidism) can lead to menstrual irregularities, including amenorrhea.
The thyroid gland also governs metabolism, the process by which your body converts food into energy. Thyroid dysfunction can result in weight changes – either weight loss or gain – which, as discussed earlier, can also impact menstruation.
7. Chronic Health Conditions
Beyond thyroid disorders, various chronic diseases can affect menstrual cycles:
- Celiac Disease: An autoimmune disorder triggered by gluten, can affect nutrient absorption and hormone regulation.
- Diabetes: Both type 1 and type 2 diabetes, if poorly managed, can impact hormonal balance and menstrual regularity.
- Pelvic Inflammatory Disease (PID): An infection of the reproductive organs, can sometimes disrupt normal menstrual function.
Furthermore, medications used to manage chronic conditions can also cause menstrual irregularities. Drugs that may lead to delayed or absent periods include:
- Anti-epileptics (for seizures)
- Anti-psychotics (for mental health conditions)
- Antidepressants
- Chemotherapy drugs
- Thyroid medications (ironically, if dosage is not properly adjusted)
When to Seek Medical Advice
If you’ve missed a period, the first step is to rule out pregnancy. If a pregnancy test is negative, or if you haven’t been sexually active since your last period, it’s advisable to consult your healthcare provider. They can assess your symptoms, review your medical history, and recommend further evaluation if necessary to determine the underlying cause of your late period.
The good news is that most of the conditions causing late or missed periods are treatable or manageable. Tracking your menstrual cycles and promptly addressing any irregularities can help ensure timely diagnosis and treatment, safeguarding your reproductive and overall health.
