Blood Sugars & Fertility

Blood sugar levels and fertility

Blood glucose levels, blood sugars, fasting, random, insulin, glucose tolerance test, GTT, glucose monitoring, CGM, insulin resistance, gestational diabetes, type 1, type 2 diabetes… Ooof! I’m a dietitian and nutritionist and when it comes to blood sugar levels, let me tell you there is a lot to understand. While nutrition forms a big part of the picture, it isn’t the only oil on the canvas.

This is a simple overview of nutrition and its impacts on blood sugar levels related to pregnancy and fertility. It is not intended to replace your medical team’s treatment plan. If you would like personalised pregnancy and fertility nutrition advice, please speak to a qualified prenatal or fertility dietitian – or contact me direct.

So let’s get into it. What are blood sugar levels, what affects them, and how can this impact fertility.

What are blood sugar levels?

Glucose is the term used to describe a sugar molecule, and from here it can be used interchangeably with sugar. Blood glucose levels (BGL) on a pathology test refer to the amount of glucose in your blood at the time your blood was taken.

It is a snapshot of your blood sugar levels at that exact time.

This is why it always important to note if your results are “fasted” or “random”. Because the foods you eat prior to a test will affect the results.

Foods containing carbohydrates (ie: starchy veggies, breads, pasta, rice, couscous, cereals and so forth) are broken down to glucose molecules when digested. Glucose is absorbed through the intestine wall and released in the blood flow. From here, glucose is transported into muscle cells to give us energy.

Now, stay with me, transport from the blood into the cell requires insulin. Insulin is a hormone made in the pancreas, it has many jobs. One of them is telling cells to let glucose in to the cell. This is where a few things can go wrong. When glucose dysregulation arises it usually comes down to 1) cells not being receptive to the action of insulin, or 2) not enough insulin being produced. That is a very simple sentence describing a very complex process.

Conditions such as Type 1 Diabetes 1, Type 2 Diabetes, Gestational Diabetes, insulin resistance, PCOS, inflammatory conditions, illness, and so forth impact how the body processes glucose. Diet and lifestyle changes form a big part of the treatment plan, sometimes conditions can be managed with diet alone. Medication is however sometimes required to help this process.

What affects blood sugars?

If you said sugar, you are right. But there is more to the story.

Medications, genetics, lifestyle, food pairing, physical activity levels, hormones, sleep, pregnancy, age, gender, stress and so forth will affect blood sugar levels too.

Take food pairings as an example. Fibre, fat and protein slow down the digestion of carbohydrates in the body. So a slice of toast with peanut butter will cause a steadier blood glucose rise in the blood than just a plain slice of bread. This concept refers to the glycemic load of a meal – which warrants its own blog, stay tuned.

Regular physical activity is shown to improve blood glucose levels by increasing insulin sensitivity (the cell’s response to insulin).

Your sleep pattern impacts your hunger and satiety hormones which will impact how much you eat and even the choice of food you choose to eat.

Suffice to say, there is a bigger picture to look at than just one meal, or one food which contains sugar.

Blood sugars and fertility

Blood glucose dysregulation can inhibit fertility. Excess insulin in the blood (hyperinsulinemia) is termed insulin resistance. This is picked up on a blood test when insulin levels are high.

This excess insulin can tell the ovaries to make more testosterone, which can stop ovulation from occurring. It is a condition with a high co-occurrence in people with PCOS (polycystic ovarian syndrome) and can result in reduced, or missed ovulation (periods).

Ovulation is essential for conception to take place, so getting insulin under control is paramount to improved hormone levels for fertility. Diet and lifestyle changes will make a huge impact here. I help women manage PCOS and insulin resistance regularly in my virtual private practice with simple and realistic dietary strategies which can have a huge impact on ovulation.

This is a huge topic and I have only scratched the surface. I strongly encourage everyone attend, and follow up, their regular health check-ups, which includes blood glucose checks, to manage conditions and/or catch complications early – because early lifestyle interventions will reduce the risk of bigger complications down the line.

Please reach out to a qualified dietitian if you have concerns about your sugar levels.


M. Derouich, A. Boutayeb The effect of physical exercise on the dynamics of glucose and insulin

Calcaterra, V.; Verduci, E.; Cena, H.; Magenes, V.C.; Todisco, C.F.; Tenuta, E.; Gregorio, C.; De Giuseppe, R.; Bosetti, A.; Di Profio, E.; et al. Polycystic Ovary Syndrome in Insulin-Resistant Adolescents with Obesity: The Role of Nutrition Therapy and Food Supplements as a Strategy to Protect Fertility. Nutrients 202113, 1848.

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