What are the 4 stages of the menstrual cycle?

The menstrual cycle is divided into four main stages, each regulated by hormones and preparing the body for a potential pregnancy. Here’s a detailed breakdown:

The 4 Stages of the Menstrual Cycle

1. Menstrual Phase (Days 1–5)

  • What happens:

    • The uterine lining (endometrium) sheds, causing menstrual bleeding

    • Blood, mucus, and tissue leave the body through the vagina

  • Hormones: Low estrogen and progesterone

  • Symptoms: Cramps, fatigue, bloating, mood changes

  • Purpose: Resets the uterus for a new cycle

2. Follicular Phase (Days 1–13)

  • What happens:

    • The pituitary gland releases FSH (follicle-stimulating hormone)

    • Several ovarian follicles start maturing, and one becomes dominant

    • Uterine lining begins to thicken again

  • Hormones: Rising estrogen

  • Symptoms: Energy and mood often improve

  • Purpose: Prepares an egg for ovulation

3. Ovulation Phase (Around Day 14)

  • What happens:

    • The dominant follicle releases a mature egg from the ovary

    • The egg travels down the fallopian tube, ready for fertilization

  • Hormones: Peak estrogen, surge of LH (luteinizing hormone)

  • Symptoms: Mild abdominal twinge, clear stretchy cervical mucus, increased libido

  • Purpose: Provides the fertile window for possible conception

4. Luteal Phase (Days 15–28)

  • What happens:

    • The empty follicle becomes the corpus luteum, releasing progesterone

    • Uterine lining thickens to support a potential pregnancy

    • If the egg is not fertilized, hormone levels drop, triggering the next period

  • Hormones: Progesterone rises, then falls if no pregnancy occurs

  • Symptoms: PMS: bloating, mood swings, breast tenderness, fatigue

  • Purpose: Prepares the uterus for implantation

Summary

Phase Days (approx.) Key Hormones Main Purpose
Menstrual 1–5 Low estrogen/progesterone Shed uterine lining, reset cycle
Follicular 1–13 Rising estrogen, FSH Prepare egg, thicken uterine lining
Ovulation ~14 LH surge, peak estrogen Release egg for fertilization
Luteal 15–28 Progesterone Prepare uterus for pregnancy

 

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