The Importance of Insulin Testing for Optimizing Fertility and Reducing Miscarriage Risk
Did you know that there is an incredibly important hormone called insulin that is rarely tested in a typical fertility assessment? Insulin’s main job is to regulate our blood sugar levels and is therefore essential to our survival. However, too much insulin can cause long or missing cycles making it difficult to conceive, it can impact the implantation of an embryo and even contribute to an increased rate of miscarriages through multiple mechanisms.
Most of my patients who are struggling to get pregnant or who have a history of miscarriages have had their blood sugar levels run and told that all looks healthy and normal. Unfortunately, insulin levels can be elevated EVEN in the presence of normal blood sugar levels, so I advocate the importance of assessing insulin levels in all my patients no matter how their blood sugar levels look.
What is Insulin?
Insulin is a hormone that is essential to keeping our blood sugar levels in a healthy range. Whenever we eat, our blood sugar goes up and this triggers insulin release from an organ called the pancreas. Insulin then takes sugar from our bloodstream and moves it into our cells so it can be used to make energy.
Healthy insulin production is therefore essential to life; however, an overproduction of insulin can cause a multitude of issues in the body. Signs of chronically elevated insulin include long or missing menstrual cycles, weight gain and weight loss resistance, darkening of the colour of skin in skin folds, skin tags, fatigue after meals, and cravings for sugar and carbohydrates.
How Does Insulin Impact Fertility?
One of the ways insulin impacts fertility is by making it difficult to ovulate. If you have long or missing cycles with an unknown cause, you should have your insulin assessed. Elevated insulin production is a major contributor to polycystic ovarian syndrome (PCOS), one of the most common reasons for missing or long cycles in menstruating women.
A large study looking at how insulin impacts fertility found that higher levels of insulin were significantly associated with a decrease in ovulation, pregnancy rates and live birth weights (1). Research has also found that elevated insulin levels can impact the healthy implantation of an embryo (2).
How Does Insulin Impact Miscarriage Risk?
Elevated insulin levels are also associated with an increased risk of miscarriage (3,4). Research has found that high insulin can impact the formation of the placenta which allows for a healthy exchange of blood and nutrition to the growing baby (5).
Other research suggests that elevated insulin can impact the expression of certain proteins that have an important role in the immune response within the endometrial lining which may also be playing a role in the increased miscarriage risk (4).
How Is Insulin Tested?
There are a couple of ways to test insulin levels. The first is to test fasting insulin and fasting glucose which will allow us to calculate a HOMA-IR score. The HOMA-IR is a measure of the extent of insulin resistance. I look for a HOMA-IR of 1.7 or below to signal healthy insulin levels.
A second test, that gives a more detailed and sensitive look at insulin production, is called the insulin glucose challenge test. This test involves fasting insulin and glucose followed by the ingestion of a sugar-rich drink and another assessment of both insulin and glucose 30 minutes, 1 hour and 2 hours after consumption. This allows us to look at both the fasting value and to assess how the body produces insulin in response to the intake of sugars.
If blood sugar looks normal, do insulin levels still need to be assessed?
Absolutely! It’s quite common for both fasting blood sugar and the three-month marker of blood sugar known as HbA1C to look healthy and normal even if there is elevated insulin.
Some people with high insulin even experience low blood sugar or hypoglycemia as part of their insulin resistance. This leaves people feeling lightheaded, shaky, ‘hangry’ and craving lots of sweets.
Is Elevated Insulin Treatable?
Yes! If you have high insulin, there are many options to reduce your levels to support your fertility and reduce your miscarriage risk. Eating a low insulin diet and getting regular movement are the foundations of any treatment plan. Some medications and supplements can provide additional support. Speak to your practitioner to discuss what the best approach is for you.
Looking For More Fertility Support?
Understanding your risk factors and getting a thorough workup when trying to conceive and if you have experienced a miscarriage before is incredibly important. You can read more about our fertility approach here, and reach out to the clinic if you have any questions about how Naturopathic Medicine can support your fertility journey!
