It’s a common concern for many women: a period that’s late or doesn’t arrive at all, especially when pregnancy isn’t a possibility. Menstrual cycles are often described as occurring every 28 days, but irregularity is actually quite typical. While sometimes these fluctuations are just a normal part of life, it’s natural to wonder when a late period might signal a need for concern.
To clarify what constitutes a late period, we turn to Karen Carlson, MD, an experienced OB-GYN. According to Dr. Carlson, “Normal cycles occur every 28 days, plus or minus a week. The cycle starts on the first day of your period. If you’ve gone over 35 days without your period, that would be considered late. Some people go for a few months at a time without a period, and that would be more concerning.”
So, generally, if your period is more than 35 days from the start of your last period, it’s considered late. Understanding the reasons behind these delays can help ease anxiety and guide you on when to seek professional medical advice. Beyond pregnancy, breastfeeding, and menopause, hormone imbalances and various health conditions are frequently the culprits behind irregular or late periods.
Here are some of the most common reasons why your period might be delayed:
Common Causes of Period Delays
1. Medications
Medications, particularly hormonal birth control, are a significant factor in menstrual cycle changes. “Contraceptive use like birth control pills can cause irregular bleeding,” explains Dr. Carlson. This is because hormonal contraceptives work by altering your natural hormone levels, which can affect your cycle. Similarly, discontinuing birth control pills or having an intrauterine device (IUD) removed can lead to a temporary period of irregularity as your body readjusts to its natural cycle. Beyond contraceptives, other medications, including treatments like chemotherapy and radiation therapy, can also disrupt menstrual regularity.
2. Body Weight – Low or High
Your body weight plays a crucial role in hormonal balance, and significant changes in either direction can impact your menstrual cycle. Dr. Carlson points out, “Low or high body weight can impact menstrual cycles. Eating disorders like anorexia and bulimia may stop someone’s period.” Eating disorders, characterized by severe undernourishment, disrupt the hormonal functions essential for regular menstruation, sometimes causing periods to cease entirely. Low body weight in general, even without an eating disorder, can mean less stored fat, which is vital for reproductive hormone production.
Conversely, being significantly overweight or obese can also lead to hormonal imbalances that cause irregular or missed periods. It’s not just those with diagnosed eating disorders who are affected; individuals with very low body fat due to intense physical activity can also experience menstrual irregularities. “Cross-country runners or someone who does rigorous ballet training may have deficient body fat, which can cause people to stop menstruating,” Dr. Carlson adds.
3. Stress
The impact of stress on overall health is often underestimated, and menstrual cycles are no exception. “Physical and mental stress can make people stop ovulating and thus have irregular menstrual cycles,” says Dr. Carlson. When you experience stress, whether it’s due to work, relationships, or major life events, your body responds by releasing stress hormones, which can interfere with the hypothalamus. This part of the brain is responsible for regulating your menstrual cycle, and chronic stress can disrupt its function, leading to irregular or missed periods. Long-term or chronic stress, lasting for weeks or months, has a more significant impact on the hypothalamus and your cycle.
4. Hormone Imbalances and Health Conditions
Hormonal imbalances stemming from underlying health conditions are another frequent cause of period irregularities. Dr. Carlson notes, “Hormonal imbalances like polycystic ovarian syndrome, or PCOS, thyroid issues, and pre-mature menopause, someone who stops menstruating before the age of 40, can make periods unpredictable or stopped.” PCOS, a common hormonal disorder, causes the body to produce excess androgens, like testosterone, which can disrupt ovulation and menstrual cycles.
Thyroid disorders, whether an overactive (hyperthyroidism) or underactive (hypothyroidism) thyroid, can also affect your period. The thyroid gland regulates metabolism and hormone levels, and imbalances can lead to late or missed periods. Premature menopause, also known as primary ovarian insufficiency, occurs when the ovaries stop functioning before age 40, leading to the cessation of menstruation.
In less common, but serious instances, uterine scarring can also be a cause. “Uterine scarring usually happens after someone has a dilation and curettage, or a D and C,” Dr. Carlson explains. “The uterine walls can scar together, preventing a normal buildup and shedding of the uterine lining.” This condition, known as Asherman’s syndrome, can disrupt the menstrual cycle significantly.
While this overview covers many common reasons for late periods, it’s not exhaustive. If you’re experiencing persistent period irregularities or your period is more than 35 days late, it’s advisable to seek guidance from a healthcare professional. For those in the Nebraska Medicine network, you can call 800.922.0000 to schedule an appointment with an OB-GYN to discuss your concerns and ensure your health and well-being.
