Why Is My Period Late? (It’s Not Always Pregnancy)
It is a common scenario: you track your cycle, expect your period, and it doesn't arrive. While pregnancy is the first assumption for sexually active individuals, a delayed menstrual cycle is often the body’s response to internal or external shifts.
A "normal" cycle ranges from 21 to 35 days. A period is generally considered late if it is more than five days past your expected start date, and "missed" if you go six weeks without bleeding.
Here are the clinical reasons your cycle might be delayed, excluding pregnancy.
1. Stress and the Hypothalamus
Chronic physical or emotional stress triggers the production of cortisol. High cortisol levels can suppress the hypothalamusthe part of the brain that controls the pituitary gland. This disruption halts the production of Gonadotropin-releasing hormone (GnRH), delaying or stopping ovulation. If you don't ovulate, your period will be delayed.
2. Significant Weight Changes
- Low Body Weight: Excessive exercise or drastic calorie restriction can lead to functional hypothalamic amenorrhea. When body fat drops too low, the body shuts down reproductive functions to conserve energy.
- Overweight/Obesity: Adipose tissue (body fat) produces estrogen. Excess estrogen can interfere with the feedback loop to the brain, causing irregular periods.
3. Polycystic Ovary Syndrome (PCOS)
PCOS is a leading cause of irregular cycles. It involves an imbalance of reproductive hormones (often elevated androgens) which prevents the egg from maturing or releasing during the follicular phase. Without ovulation, the uterine lining does not shed on a predictable schedule.