Perimenopause can cause irregular periods, but pregnancy is still possible. Know the causes, warning signs, and when to see a doctor.

New Delhi: Perimenopause is the transitional phase before menopause when the ovaries gradually produce less estrogen and progesterone. Unlike menopause, hormone levels during perimenopause do not steadily decline — they fluctuate, sometimes dramatically.

Most women enter this stage in their 40s, with the average age between 45–47 years. Menopause, however, is officially confirmed only after 12 consecutive months without a period, typically around age 51.
This transition lasts about four years on average, but for some women, it may range from a few months to over a decade.

Why Periods Become Irregular

Menstrual cycles depend on a delicate hormonal balance involving estrogen, progesterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH). These hormones are regulated by the ovaries, pituitary gland, and hypothalamus and control ovulation, buildup of the uterine lining, and shedding. When this balance is disrupted, cycles become irregular.

A normal cycle ranges from 21 to 35 days, averaging 28–29 days, with bleeding lasting two to seven days. Irregularity can mean shorter or longer cycles, skipped periods, unpredictable timing, heavy or light flow, or spotting between periods. Each woman’s experience can vary widely.

Life Stage Transitions

Puberty: During the first few years after menarche (ages 9–15), cycles are often irregular because the hormonal system is still maturing. Ovulation may not occur monthly.
Perimenopause: Fluctuating estrogen and progesterone levels make ovulation inconsistent. Periods may occur every two to three weeks or disappear for months. It is one of the most common causes of irregular cycles in women over 40.

Stress and Lifestyle Factors

Stress increases cortisol, which can disrupt the hypothalamic-pituitary-ovarian axis, interfering with ovulation and causing missed or irregular periods.
Other contributing lifestyle factors include:

• Rapid weight gain or loss
• Eating disorders such as anorexia or bulimia (reducing estrogen production)
• Excessive exercise lowering body fat and energy needed for ovulation
• Poor sleep, drastic diet changes, or travel disrupting circadian rhythms
These causes are often temporary and improve with lifestyle adjustments.

Hormonal Imbalances and Medical Conditions

Polycystic Ovary Syndrome (PCOS): A common endocrine disorder affecting 10–15% of reproductive-age women. High androgens and insulin resistance prevent regular ovulation, leading to infrequent or absent periods. Symptoms include acne, excess hair growth, and weight concerns.

Thyroid Disorders: Both hypothyroidism and hyperthyroidism can cause irregular, heavy, light, or absent periods. Symptoms may include fatigue, weight changes, hair loss, and temperature intolerance.

Elevated Prolactin: High prolactin levels from pituitary disorders, medications, or stress suppress ovulation.

Other endocrine problems, including adrenal or pituitary disorders such as Cushing’s syndrome, may also disrupt cycles.

Medications and Contraception

Hormonal birth control (pills, patches, intrauterine devices) may cause irregular bleeding, especially during initial months. After discontinuation, cycles may take time to normalize.

Certain medications — antidepressants, antipsychotics, blood thinners, chemotherapy, steroids, or hormone therapies — can also affect menstrual regularity.

Pregnancy and Related Factors

Pregnancy commonly causes missed periods. Implantation bleeding may resemble a light period, causing confusion. Breastfeeding raises prolactin levels, suppressing ovulation (lactational amenorrhea). Recent miscarriage or abortion can temporarily disrupt cycles.

Other Medical Conditions

Endometriosis, uterine fibroids, and polyps can cause irregular or heavy bleeding. Chronic illnesses such as diabetes, autoimmune diseases, infections, or structural reproductive tract issues may also contribute.

When to See a Doctor

Occasional irregularity due to stress or travel is usually not serious. However, medical consultation is recommended if:

• Periods remain irregular for several months
• You miss periods for three months or more (not pregnant)
• Bleeding is extremely heavy (soaking a pad/tampon hourly) or lasts more than seven days
• Severe pain accompanies bleeding
• Symptoms such as unexplained weight changes, fatigue, hair loss, acne, excess hair growth, hot flashes, or mood changes occur
• You are trying to conceive and have irregular cycles

Doctors may recommend blood tests (hormones, thyroid, prolactin), ultrasound, or cycle tracking. Treatment depends on the cause and may include lifestyle changes, medications for PCOS or thyroid disorders, hormonal therapy, or addressing underlying conditions.

Irregular periods are often not a disease but a symptom. Understanding the cause enables effective management and supports reproductive health. Consulting a gynecologist or endocrinologist ensures proper evaluation and care.