Fertility Through the Years

Let’s take a quick trip through women’s fertility over their life!
Age is one way to decide where we’re at, but let’s be honest—our bodies don’t always follow the textbook. You may start ovulating at 10 years old, or maybe not until you’re 15. You might begin perimenopause at 35, or you may still be cycling regularly into your late 50s. This is why listening to your body and understanding your symptoms is far more powerful than simply looking at your birthdate—or even a single blood test. I’ll explain more on that shortly (I can already hear the questions!).

The Fertility Timeline: What to Expect at Each Stage

1. Early Teens (10–15 years):
The menstrual cycle begins—though irregular, it’s the body’s way of practicing. It can take years to establish a consistent ovulatory rhythm. PMS, mood swings, heavy or painful periods, or acne are common issues at this stage, often due to immature hormone signaling rather than underlying disease.

2. Late Teens to Late 20s:
Peak fertility typically happens in your 20s. Cycles tend to become more regular, ovulation is more consistent, and hormonal patterns stabilize. But stress, nutrient deficiencies, over-exercising, or conditions like PCOS and endometriosis can still disrupt the cycle and cause pain, irregularity, or infertility.

3. 30s:
Fertility gradually starts to decline around the mid-30s, although many women still conceive naturally. This decade can be a mix of baby-making and burnout. The juggle of career, parenting, and life stressors can throw hormones off-balance, especially if your self-care has taken a backseat. This is also when symptoms like PMS, shorter cycles, or increased anxiety can emerge—early signs of shifting hormone patterns.

4. 40s (aka the Perimenopausal Years):
This is where things really start to shift. Hormone levels don’t just drop—they fluctuate wildly. One month might feel “normal,” the next, you’re riding an emotional rollercoaster, waking at 3 a.m., and wondering why your jeans don’t fit. Irregular cycles, heavier or lighter bleeding, mood swings, brain fog, and hot flushes may begin to show up.

5. 50s and Beyond:
Most women reach menopause (defined as 12 months without a period) between 45 and 55. After that, hormone levels settle at lower levels. But post-menopause isn’t a hormonal desert—oestrogen, testosterone, and progesterone are still present, just in smaller amounts. Many women feel a new kind of clarity, strength, and purpose here—if they've supported their body through the transition.

Why Hormonal Blood Tests Often Fall Short—Especially in Perimenopause

Hormonal testing sounds like a reliable way to understand what’s going on, but in reality—it’s often misleading. Here's why:

1. Hormones Fluctuate—A Lot:
   In perimenopause, your hormone levels can vary dramatically not just from month to month, but even from day to day. A single blood test offers a snapshot—it's like judging a movie from one frame. You might catch your estrogen spiking, your progesterone crashing, or everything in limbo depending on the day of your cycle.

2. Stress Plays a Huge Role:
   Chronic stress, poor sleep, and emotional burnout impact your adrenal function—and therefore your sex hormones. Cortisol (your main stress hormone) can steal the building blocks your body needs to make progesterone, leading to symptoms like anxiety, insomnia, and heavy periods. No blood test captures that full picture.

3. Symptoms Speak Volumes:
   Hot flushes, irregular cycles, mood swings, weight changes, and fatigue aren’t “just in your head”—they are signs your body is shifting. Tuning into your symptoms and tracking your cycle often tells you far more than lab work can.

4. Comprehensive Testing Is Better:
   If testing is needed, options like the DUTCH test (Dried Urine Test for Comprehensive Hormones) can be far more insightful. It tracks hormone metabolites over a full cycle, gives insight into cortisol patterns, and shows how your body is processing hormones—not just how much is floating around at one point in time.

Your fertility—and your hormonal health—aren’t defined by a number on a lab report or your age. It’s a dynamic, shifting dance influenced by your lifestyle, stress, sleep, nutrition, and emotional well-being. Understanding the full picture means stepping back and looking at your symptoms, your patterns, and your life.

If you're wondering where you’re at in this hormonal journey, or your current symptoms don’t make sense, I’m here to help you make sense of it all—with a whole-person, whole-cycle approach.