Understanding the Reproductive Cycle: How Hormones Rise, Fall, and Affect Your Body

The reproductive (menstrual) cycle isn’t “just a period.” It’s a complex, beautifully coordinated cycle of hormones that influence everything from energy and mood to digestion, sleep, pain, and inflammation.

Understanding what’s happening in your body — and when — can help explain why some days feel manageable while others feel overwhelming, especially for those living with endometriosis, adenomyosis, PCOS, or other hormone-sensitive conditions.

Let’s break it down in a simple, easy-to-follow way.

The Four Phases of the Reproductive Cycle

A typical cycle lasts about 28 days, though anything from 21–35 days can be normal. Hormone levels shift throughout the cycle in four main phases:

1. Menstrual Phase

2. Follicular Phase

3. Ovulation

4. Luteal Phase

Each phase has a unique hormone “signature” — and your body responds accordingly.

1. Menstrual Phase (Days 1–5)

Hormones: LOW estrogen & LOW progesterone

This phase begins on the first day of bleeding.

What’s happening hormonally:

• Estrogen drops

• Progesterone drops

• The uterus sheds its lining (your period)

How this can feel in the body:

• Low energy and fatigue

• Increased pain and cramping

• Headaches or migraines

• Digestive changes (diarrhea or nausea)

• Increased inflammation

• Lower mood or emotional sensitivity

  
  

For people with endometriosis, this phase can be especially difficult due to higher prostaglandins, which increase uterine contractions and inflammation.

💛 Rest is not laziness during this phase — it’s biological.

2. Follicular Phase (Days 6–13)

Hormones: Estrogen RISING, progesterone LOW

This phase starts after bleeding ends and continues until ovulation.

What’s happening hormonally:

• Estrogen begins to rise

• Follicle-stimulating hormone (FSH) helps mature an egg

• Progesterone remains low

How this can feel in the body:

• Increasing energy and mental clarity

• Improved mood and motivation

• Reduced pain and inflammation for some

• Better digestion

• Increased resilience to stress

  
  

This is often when people feel more capable, focused, and optimistic.

💡 This is often a good time for planning, learning, and starting new projects.

3. Ovulation (Around Day 14)

Hormones: Estrogen PEAKS, testosterone rises briefly

Ovulation occurs when a mature egg is released from the ovary.

What’s happening hormonally:

• Estrogen reaches its highest point

• Luteinizing hormone (LH) surges

• Testosterone briefly increases

• Progesterone will begin rising after ovulation

How this can feel in the body:

• Peak energy and confidence

• Increased social connection

• Higher libido

• Better pain tolerance for some

• Improved communication skills

  
  

However, for some — especially those with endometriosis — ovulation can trigger:

• One-sided pelvic pain

• Inflammation

• Bloating or nausea

  
  

⚠️ Ovulation pain is not “all in your head.” It can be very real and intense.

4. Luteal Phase (Days 15–28)

Hormones: Progesterone HIGH, estrogen fluctuates then falls

This phase begins after ovulation and ends when the next period starts.

What’s happening hormonally:

• Progesterone rises to support a potential pregnancy

• Estrogen has a smaller second rise, then drops

• If pregnancy doesn’t occur, both hormones fall

  
  

How this can feel in the body:

• Slower digestion and bloating

• Increased breast tenderness

• Fatigue or heaviness

• Increased pain sensitivity

• Anxiety or low mood

• PMS or PMDD symptoms for some

  
  

Progesterone has a calming effect, but when levels drop suddenly, it can lead to mood changes, sleep disruption, and pain flares.

For those with endometriosis, this phase can be associated with:

• Increased inflammation

• Pelvic pain flares

• Worsening bowel or bladder symptoms

  
  

💛 This is a time to slow down and prioritize gentle care.

How Hormonal Fluctuations Affect the Whole Body

Hormones don’t just affect the reproductive system — they influence nearly every system in the body:

• Brain: mood, memory, anxiety, migraines

• Immune system: inflammation and immune responses

• Gut: digestion, bloating, bowel habits

• Muscles & joints: pain sensitivity and stiffness

• Sleep: quality and duration

• Skin: acne, dryness, or sensitivity

  
  

This is why symptoms can change dramatically throughout the month.

Why This Matters for Endometriosis & Chronic Pelvic Pain

Endometriosis is hormonally responsive and inflammatory, meaning hormonal shifts can:

• Trigger pain flares

• Affect lesion activity

• Worsen fatigue and brain fog

• Influence mental health

  
  

Understanding your cycle can help with:

• Symptom tracking

• Medical appointments

• Planning rest and activity

• Reducing self-blame on hard days

  
  

🟡 You are not “weak” — your body is responding to real biological changes.

Final Thoughts

Learning your hormonal rhythm can be empowering. It allows you to work with your body rather than fighting against it — especially when living with a chronic condition like endometriosis.

Your cycle is not a flaw. Your symptoms are not imagined. And your experience deserves understanding and care.