What Is a Period, Medically Speaking?
A period (menstruation) is the shedding of the endometrial lining of the uterus, triggered by the drop in reproductive hormones when pregnancy doesn’t occur.
It’s part of the larger menstrual cycle, which typically lasts 24–35 days and involves ovulation, hormonal fluctuations, and physiological changes throughout the body.
Phases of the Menstrual Cycle (4 Key Stages)
1. Menstrual Phase (Day 1–5)
What happens: Shedding of the functional layer of the endometrium through the vagina.
Hormones: Estrogen and progesterone are at their lowest levels.
Symptoms: Cramps (due to prostaglandins), fatigue, mood swings, headaches.
📚 Research Insight:
Prostaglandins (hormone-like substances) cause uterine contractions. Excessive levels are linked to dysmenorrhea (painful periods).
2. Follicular Phase (Day 1–13)
- What happens: The pituitary gland releases FSH (follicle-stimulating hormone), stimulating follicles in the ovary to mature.
- Hormones: Estrogen rises, helping the endometrium regenerate.
- Physiological effects: Improved mood, rising energy levels, clearer skin.
3. Ovulation (Day 14 ± 2)
- What happens: A mature follicle releases an egg into the fallopian tube.
- Hormones: A sudden LH surge (luteinizing hormone) triggers ovulation.
- Fertility window: ~5 days surrounding ovulation.
💡 Pro Tip:
Cervical mucus becomes stretchy and transparent (like egg whites), and basal body temperature slightly rises.
📚 PubMed Study:
Ovulation typically occurs 24–36 hours after the LH peak, with ovum viability lasting up to 24 hours.
4. Luteal Phase (Day 15–28)
What happens: The ruptured follicle forms the corpus luteum, which secretes progesterone.
Purpose: Prepares uterus for pregnancy by thickening the endometrium.
If no fertilization: Corpus luteum breaks down → progesterone drops → menstruation begins.
🧠 Symptoms of progesterone drop:
PMS (irritability, bloating, tender breasts, cravings)
Anxiety, acne flare-ups, sleep disturbances
📚 Evidence:
High progesterone levels cause thermogenic effects, which is why women often experience a slight rise in core body temperature post-ovulation.
When Is It NOT Normal?
Red flags that warrant medical attention:
| Symptom | Possible Cause |
|---|---|
| Periods longer than 7 days | Menorrhagia, PCOS, fibroids |
| Skipping periods repeatedly | PCOS, thyroid dysfunction |
| Debilitating cramps | Endometriosis, adenomyosis |
| Excessive hair growth + acne | Hyperandrogenism |
Tip: Keep a cycle log using apps like Clue or Flo — helps with early detection of issues.
FAQs
Is it normal to feel exhausted before your period?
Yes. Progesterone affects energy metabolism and serotonin levels, which can cause fatigue and mood dips.
Why do I crave junk food before my period?
Hormonal fluctuations (especially serotonin and insulin sensitivity changes) trigger cravings for sugar and salt.
Can stress delay my period?
Yes — chronic stress elevates cortisol, which interferes with GnRH, disrupting ovulation.
What Helps During Periods?
| Solution | Effect |
|---|---|
| NSAIDs (like ibuprofen) | Reduces prostaglandin activity, easing cramps |
| Heat therapy | Relaxes uterine muscles |
| Light exercise | Improves blood flow, releases endorphins |
| Magnesium & B6 | May reduce PMS severity |
| Iron-rich foods | Replenish blood loss |
Final Thoughts
Your menstrual cycle is a biological feedback loop — every symptom you feel has a physiological reason behind it. Understanding what’s happening can help you ditch the shame, spot abnormal signs early, and better advocate for your health.
🩺 It’s your body. You deserve to understand it — fully, honestly, and without myths.
References
ACOG Practice Bulletin No. 128: Diagnosis of Abnormal Uterine Bleeding
National Institutes of Health (NIH): Hormonal Control of Menstrual Cycle
Journal of Clinical Endocrinology & Metabolism, 2018: Progesterone and Thermoregulation
PubMed: Ovulatory Cycle Predictors (PMID: 29075715)
American Academy of Family Physicians: Managing PMS and PMDD
Rakshit Deori is a final-year MBBS student passionate about simplifying medical science for the digital generation. On HealthExplained.in, he breaks down complex health topics into clear, honest, and relatable insights — no jargon, no fluff. His mission: to make evidence-based health information accessible, especially for young minds navigating a world full of misinformation.
