There is a blood test that could explain why you are not ovulating regularly.
A test that could explain why your IVF cycles have not worked.
A test that could explain years of unexplained infertility in women with and without a PCOS diagnosis.
It is not a new test. It is not expensive. It is not complicated.
And there is a very good chance you have never had it done.
It is called fasting insulin.
And it is one of the most powerful and most overlooked markers in female fertility medicine.
WHAT IS FASTING INSULIN?
Insulin is the hormone produced by your pancreas in response to glucose, the sugar that enters your bloodstream after you eat.
Its job is to act like a key, unlocking your cells so that glucose can enter and be used for energy.
When everything is working well, a small amount of insulin does that job efficiently. Glucose enters the cells, blood sugar returns to baseline, and insulin levels drop back down.
But when cells become resistant to insulin, less responsive to its signal the pancreas has to produce more and more insulin to get the same result. Blood sugar may stay perfectly normal, because the pancreas is compensating. But insulin levels in the blood are elevated.
This is insulin resistance and it is extraordinarily common; estimated to affect up to 50% of women of reproductive age, the majority of whom have no idea.
WHY DOESN'T MY DOCTOR TEST IT?
This is the question I am asked most often.
The answer is simple: standard screening for metabolic health focuses on glucose, not insulin.
Fasting glucose. HbA1c. These are the markers that appear on a routine blood panel. They measure
blood sugar the downstream effect of insulin's work.
But glucose is the last thing to rise in insulin resistance.
By the time your fasting glucose climbs above the normal range, your insulin has often been elevated for months sometimes years. Your pancreas has been quietly overworking, compensating for cellular resistance, and no alarm has been raised because the marker everyone is watching, glucose still looks completely fine.
The result is that insulin resistance goes undetected in a vast number of women until it has been present long enough to cause downstream problems.
In fertility medicine, those downstream problems are significant.
WHAT DOES INSULIN RESISTANCE DO TO FERTILITY?
This is where it gets important.
Insulin receptors are found throughout the reproductive system in the ovaries, in the endometrium, in the pituitary gland. Insulin is not just a blood sugar hormone. It is a signalling molecule that directly influences reproductive function.
Here is what elevated insulin does in the body:
- It stimulates the ovaries to produce androgens, male hormones like testosterone. Elevated androgens disrupt the normal development of follicles, interfere with ovulation, and create the hormonal environment characteristic of PCOS.
- It disrupts the LH surge, the hormonal signal that triggers ovulation. Without a clean LH surge, ovulation either does not occur or is delayed and irregular.
- It impairs endometrial receptivity, the ability of the uterine lining to receive and implant an embryo. Even when ovulation occurs and fertilisation happens, elevated insulin can prevent successful implantation.
- It increases inflammation and chronic low-grade inflammation is independently associated with impaired egg quality, failed implantation, and early pregnancy loss.
All of this can be happening with a completely normal fasting glucose. All of it invisible on a standard blood panel.
THE NUMBERS THAT MATTER
The standard laboratory reference range for fasting insulin is 2-25 mIU/L.
Most labs will not flag a result as concerning until it exceeds 25.
But the evidence-based optimal range for women trying to conceive is 2-8 mIU/L.
That gap between 8 and 25 is where a significant amount of female fertility dysfunction lives, entirely undetected.
A fasting insulin of 14 would pass through your results without comment. Your doctor would not call. Nothing would be flagged. You would be told everything looks normal.
But a fasting insulin of 14, combined with a fasting glucose of 5.0, gives a HOMA-IR score of 3.1.
HOMA-IR calculated as (fasting glucose x fasting insulin) divided by 22.5 is the most sensitive marker of insulin resistance available from a simple blood test.
A score above 1.5 indicates early insulin resistance.
A score above 2.5 indicates moderate resistance.
A score of 3.1 indicates significant resistance that is almost certainly disrupting reproductive function.
And it would never have been found without testing fasting insulin.
WHO SHOULD BE TESTED?
Every woman trying to conceive should have her fasting insulin tested. But it is especially important if you have any of the following:
- A PCOS diagnosis or suspected PCOS
- Irregular or absent periods
- Unexplained infertility
- Failed IVF cycles with good quality embryos
- Recurrent miscarriage
- Excess weight, particularly around the abdomen
- A family history of type 2 diabetes or gestational diabete
- Sugar cravings, energy crashes, or difficulty losing weight
- Skin tags or darkened skin in body folds (acanthosis nigricans)
- Elevated testosterone or DHEA-S on previous testing
You do not need all of these features to warrant testing. Any one of them is sufficient reason to ask.
HOW TO REQUEST THE TEST
Fasting insulin is not always included in standard panels. You may need to ask for it specifically.
Here is exactly what to say:
"I would like to request a fasting insulin alongside my fasting glucose. I understand that insulin resistance can be present before glucose becomes elevated, and I would like to calculate my HOMA-IR as part of my preconception assessment."
You will need to fast for a minimum of 8-10 hours before the test, water only. Book it as a morning appointment and do not eat breakfast beforehand.
WHAT IF MY RESULT IS OUTSIDE OPTIMAL?
The good news about insulin resistance is that it is one of the most responsive conditions to lifestyle intervention.
If your fasting insulin is above 8 mIU/L or your HOMA-IR is above 1.5, here is where to start:
- Dietary changes first. A low-glycaemic diet. reducing refined carbohydrates, sugar, and ultra-processed foods, and increasing protein, healthy fats, and fibre is the most powerful first-line intervention for insulin resistance. Results can be seen within 4-8 weeks of consistent change.
- Inositol supplementation. Myo-inositol and d-chiro-inositol in a 40:1 ratio have the strongest evidence base of any supplement for improving insulin sensitivity in women with PCOS and ovulatory dysfunction. The research on inositol is extensive and the safety profile is excellent.
- Strength training. Resistance exercise increases the sensitivity of muscle cells to insulin one of the most effective non-dietary interventions available. Even two sessions per week produces measurable improvement in insulin markers.
- Sleep. Poor sleep independently worsens insulin resistance. Seven to nine hours of quality sleep is not optional when you are trying to correct a metabolic pattern.
- Medication if needed. If lifestyle intervention alone is insufficient, metformin and berberine both have evidence for improving insulin sensitivity and restoring ovulation in women with insulin-driven fertility dysfunction. Discuss these options with your doctor or functional medicine practitioner.
Retest at 8-12 weeks to track your progress.
THE BOTTOM LINE
Fasting insulin is a simple, inexpensive, widely available blood test.
It takes one extra tube of blood at the same appointment as your routine panel.
And it could explain everything.
If you have been trying to conceive without success, if you have been through IVF cycles that have not worked, if you have been told there is nothing to find please ask for this test.
You deserve a complete picture. Not just the markers that are routinely ordered, but the ones that actually tell the story.
The Lab Interpretation Guide for Fertility Health covers fasting insulin, HOMA-IR, and 23 other fertility markers in full including the evidence-based optimal ranges, what your result means, and exactly what to do next.
→ Get the Lab Interpretation Guide here $47
https://payhip.com/b/0rSJl
A FINAL WORD
Insulin resistance is not a life sentence. It is a signal one your body is sending because it needs support.
And now you know to listen for it.
Dr. Rose
No comments:
Post a Comment