Gestational diabetes is a very common condition in pregnancy, impacting at least 1 in 20 women. It is even more common in women who become pregnant after the age of 35, have polycystic ovarian syndrome, a family history of diabetes, or who are overweight. If you fall into one of these categories or have already been diagnosed with insulin resistance or gestational diabetes, it is useful to learn about the latest research on natural ways to help prevent and reduce the severity of this condition. Doing so is not only beneficial for your own health during pregnancy but may also reduce the risk of several complications and help to protect your baby’s brain.   

What is Gestational Diabetes?

At some point in your pregnancy, your doctor will likely perform an oral glucose tolerance test. This typically involves consuming a drink containing a set amount of glucose and then having blood tests after one to three hours. If your blood glucose level stays too high, this typically indicates that the pancreas is not producing enough insulin, and you may be diagnosed with gestational diabetes.

In healthy women insulin production normally increases significantly during pregnancy. During the second and third trimester, it is normal for the mother’s cells to become less sensitive to insulin’s message to take up glucose, developing a mild form of insulin resistance.[i] To compensate for this the pancreas usually produces more insulin. In women with gestational diabetes this does not occur, for reasons that are not fully understood. 

The combination of insulin resistance and insufficient production of insulin means that more glucose stays in the blood stream, rather than getting into the cells where it is needed. This results in high blood glucose levels, which carries a range of potential consequences for both mother and baby.

In particular, gestational diabetes is associated with a higher risk of both preeclampsia and pre-term birth.[ii] Babies born to mothers with this condition are also more likely to be large for gestational age, which leads to a greater rate of birth complications and C-sections.[iii] Although the research has produced somewhat conflicting results, gestational diabetes may also be associated with poorer neurodevelopmental outcomes for infants, such as lower IQ and a higher risk of ADHD.[iv]

Yet all these risks appear to be reduced or eliminated when mothers gain greater control over their blood sugar levels— whether through exercise, dietary changes, medication, or a combination of these strategies. Studies have shown, for example, that switching to a diet emphasizing high-fiber, low-glycemic index carbohydrates (such as legumes and unprocessed grains) can significantly improve blood sugar control in gestational diabetes. This reduces the need for insulin treatment and the occurrence of typical pregnancy complications.[v] Regular resistance exercise can also have a significant positive impact on blood sugar levels and the need for insulin treatment.[vi] 

If you are diagnosed with gestational diabetes or are at a particularly high risk due to weight or a history of PCOS, these lifestyle changes are likely to be recommended by your doctor, possibly along with medication such as metformin or insulin. But there is one more strategy that can be very effective for treating and even preventing gestational diabetes that your doctor may not mention, even though it is backed by a significant body of research: supplementing with myo-inositol. 

Myo-Inositol for Gestational Diabetes

Myo-inositol is a naturally occurring sugar molecule found in small amounts in a wide variety of foods. The body uses myo-inositol to produce other compounds called inositol phosphoglycans (IPGs), which are involved in glucose metabolism.  Specifically, IPGs help to activate the glucose transporters that let glucose into cells, acting in a similar way to insulin. Myo-inositol can therefore help to compensate for a lack of insulin or insulin resistance and prevent spikes in blood sugar.

This ability to control blood glucose levels has proven very useful in women with PCOS who are trying to conceive, with research showing that it can restore ovulation and improve fertility.[vii] But the benefits do not end when women become pregnant. Researchers have found that when women with PCOS continue taking myo-inositol during pregnancy they are much less likely to go on to develop gestational diabetes.

This led researchers to ask whether myo-inositol could also help to prevent gestational diabetes in other groups of women at high risk for developing the condition, such as those who are overweight, obese, or have a family history of diabetes. To answer this question, women in these categories were given two grams of myo-inositol twice a day from the end of the first trimester until delivery.[viii] This placebo-controlled trial found that myo-inositol more than halved the risk of developing gestational diabetes. In overweight women, for example, the rate dropped from 27% to 12%. 

Other researchers have now reported a similar pattern, with at least five randomized controlled trials finding a similar reduction in the risk of developing gestational diabetes in high-risk women.[ix] 

Myo-inositol also has significant value for women who have already been diagnosed with gestational diabetes. By improving the way that glucose transporters work, myo-inositol reduces the severity of the blood sugar and insulin abnormalities characteristic of gestational diabetes. Specifically, myo-inositol reduces insulin resistance and helps to prevent high glucose levels.[x]

This has many downstream benefits. Studies have found, for example, that women taking myo-inositol required less insulin therapy and had significantly smaller babies with fewer episodes of neonatal hypoglycemia.[xi] Perhaps most importantly, myo-inositol also significantly reduces the risk of pre-term birth. [xii]  In one study of women at high risk of developing gestational diabetes, taking myo-inositol throughout pregnancy reduced the risk of preterm birth from 8% to 3%.[xiii]  This would be expected to have a range of benefits for their babies including reduced medical complications and healthier brain development. 

The appropriate dose of myo-inositol appears to be two grams, twice per day, for a total of four grams per day. (Studies using a lower dose of just one gram per day found little benefit.[xiv])  It can be started at any point during pregnancy, with your doctor’s approval. Given the dosage, many people find the powder form more convenient than taking a large number of capsules. It can be taken with or without food and may improve sleep when taken before bed.   

Although myo-inositol appears to be one of the most effective ways to prevent and treat gestational diabetes, other supplements offer benefits too. Specifically, vitamin D and omega-3 fatty acids have an important role to play.  

Vitamin D is useful because it helps the body both produce and use insulin, reducing insulin resistance and improving the ability of cells to take up glucose.[xv] As a result, women with higher levels of vitamin D at the beginning of pregnancy are much less likely to develop gestational diabetes. [xvi]  This protective effect starts to become evident at 50 nmol/L and is even clearer at higher vitamin D levels.[xvii] 

Supplementing with vitamin D can also improve blood sugar control in those who already have gestational diabetes.[xviii] In one study, supplementing with the equivalent of 3500 IU per day (as 50,000 IU every two weeks) was found to significantly improve insulin resistance in pregnant women, whereas lower doses of vitamin D had little impact.[xix] 

The other supplement found to be helpful is fish oil, providing omega-3 fatty acids. That is because omega-3 fats can boost the production of insulin and improve insulin sensitivity.[xx] In one double-blind study of omega-3 supplements in women with gestational diabetes, researchers found a significant reduction in the rate of newborn complications. The percentage of babies with jaundice, for example, dropped from 33% to 8%.[xxi]

The combination of vitamin D and fish oil also appears to produce even better results than either alone, with a significant reduction in fasting glucose levels and insulin resistance.[xxii]

When the research is viewed as a whole, it is clear that being diagnosed with gestational diabetes or falling into a high-risk category is just a starting point. There is a great deal we can do to address the underlying problems of high blood sugar levels and poor insulin function using well-researched supplements found to improve pregnancy outcomes.

Points to Remember

• You may be at a higher risk of developing gestational diabetes if you are overweight, have PCOS, or a family history of diabetes. 
• Gestational diabetes carries potential complications for mother and baby, but these complications can often be avoided by managing blood sugar levels with diet, exercise, and medication if needed.
• Myo-inositol is particularly helpful for preventing and managing gestational diabetes. The typical dose is 2 grams, twice per day.

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[ii] Köck, K., Köck, F., Klein, K., Bancher-Todesca, D., & Helmer, H. (2010). Diabetes mellitus and the risk of preterm birth with regard to the risk of spontaneous preterm birth. The Journal of Maternal-Fetal & Neonatal Medicine, 23(9), 1004-1008.

Hedderson, M. M., Ferrara, A., & Sacks, D. A. (2003). Gestational diabetes mellitus and lesser degrees of pregnancy hyperglycemia: association with increased risk of spontaneous preterm birth. Obstetrics & Gynecology, 102(4), 850-856.

[iii] Casey, B. M., Lucas, M. J., McIntire, D. D., & Leveno, K. J. (1997). Pregnancy outcomes in women with gestational diabetes compared with the general obstetric population. Obstetrics & Gynecology, 90(6), 869-873.

[iv] Fraser, A., Nelson, S. M., Macdonald-Wallis, C., & Lawlor, D. A. (2012). Associations of existing diabetes, gestational diabetes, and glycosuria with offspring IQ and educational attainment: the Avon Longitudinal Study of Parents and Children. Experimental diabetes research, 2012.

Nelson, C. A., Wewerka, S., Thomas, K. M., deRegnier, R. A., Tribbey-Walbridge, S., & Georgieff, M. (2000). Neurocognitive sequelae of infants of diabetic mothers. Behavioral neuroscience, 114(5), 950.

Torres-Espinola, F. J., Berglund, S. K., García-Valdés, L. M., Segura, M. T., Jerez, A., Campos, D., … & Campoy, C. (2015). Maternal obesity, overweight and gestational diabetes affect the offspring neurodevelopment at 6 and 18 months of age–a follow up from the PREOBE cohort. PloS one, 10(7), e0133010.

Cai, S., Qiu, A., Broekman, B. F., Wong, E. Q., Gluckman, P. D., Godfrey, K. M., … & Meaney, M. J. (2016). The influence of gestational diabetes on neurodevelopment of children in the first two years of life: a prospective study. PloS one, 11(9), e0162113.

Ornoy, A. (2005). Growth and neurodevelopmental outcome of children born to mothers with pregestational and gestational diabetes. Pediatric endocrinology reviews: PER, 3(2), 104.

Xiang, A. H., Wang, X., Martinez, M. P., Getahun, D., Page, K. A., Buchanan, T. A., & Feldman, K. (2018). Maternal gestational diabetes mellitus, type 1 diabetes, and type 2 diabetes during pregnancy and risk of ADHD in offspring. Diabetes Care, 41(12), 2502-2508.

Zhao, L., Li, X., Liu, G., Han, B., Wang, J., & Jiang, X. (2019). The association of maternal diabetes with attention deficit and hyperactivity disorder in offspring: a meta-analysis. Neuropsychiatric disease and treatment, 15, 675.

[v] Louie, J. C. Y., Brand-Miller, J. C., & Moses, R. G. (2013). Carbohydrates, glycemic index, and pregnancy outcomes in gestational diabetes. Current Diabetes Reports, 13(1), 6-11.

Moses, R. G., Barker, M., Winter, M., Petocz, P., & Brand-Miller, J. C. (2009). Can a low–glycemic index diet reduce the need for insulin in gestational diabetes mellitus?: A randomized trial. Diabetes care, 32(6), 996-1000.

Wei, J., Heng, W., & Gao, J. (2016). Effects of low glycemic index diets on gestational diabetes mellitus: a meta-analysis of randomized controlled clinical trials. Medicine, 95(22).

[vi] de Barros, M. C., Lopes, M. A., Francisco, R. P., Sapienza, A. D., & Zugaib, M. (2010). Resistance exercise and glycemic control in women with gestational diabetes mellitus. American journal of obstetrics and gynecology, 203(6), 556-e1.

[vii] Unfer, V., Facchinetti, F., Orrù, B., Giordani, B., & Nestler, J. (2017). Myo-inositol effects in women with PCOS: a meta-analysis of randomized controlled trials. Endocrine Connections, 6(8), 647-658.

[viii] D’Anna, R., Scilipoti, A., Giordano, D., Caruso, C., Cannata, M. L., Interdonato, M. L., … & Di Benedetto, A. (2013). myo-Inositol supplementation and onset of gestational diabetes mellitus in pregnant women with a family history of type 2 diabetes: a prospective, randomized, placebo-controlled study. Diabetes care, 36(4), 854-857.

[ix] Zhang, H., Lv, Y., Li, Z., Sun, L., & Guo, W. (2019). The efficacy of myo-inositol supplementation to prevent gestational diabetes onset: a meta-analysis of randomized controlled trials. The Journal of Maternal-Fetal & Neonatal Medicine, 32(13), 2249-2255.

[x] Pintaudi, B., Di Vieste, G., Corrado, F., Lucisano, G., Giunta, L., D’ANNA, R., & Di Benedetto, A. (2018). Effects of myo-inositol on glucose variability in women with gestational diabetes. European review for medical and pharmacological sciences, 22(19), 6567-6572.

Costabile, L., & Unfer, V. (2017). Treatment of gestational diabetes mellitus with myo-inositol: analyzing the cutting edge starting from a peculiar case. European Review for Medical and Pharmacological Sciences, 21(Supplement 2), 73-76.

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[xi] Matarrelli, B., Vitacolonna, E., D’angelo, M., Pavone, G., Mattei, P. A., Liberati, M., & Celentano, C. (2013). Effect of dietary myo-inositol supplementation in pregnancy on the incidence of maternal gestational diabetes mellitus and fetal outcomes: a randomized controlled trial. The Journal of Maternal-Fetal & Neonatal Medicine, 26(10), 967-972.

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[xii] Zhang, H., Lv, Y., Li, Z., Sun, L., & Guo, W. (2019). The efficacy of myo-inositol supplementation to prevent gestational diabetes onset: a meta-analysis of randomized controlled trials. The Journal of Maternal-Fetal & Neonatal Medicine, 32(13), 2249-2255.

[xiii] Santamaria, A., Alibrandi, A., Di Benedetto, A., Pintaudi, B., Corrado, F., Facchinetti, F., & D’Anna, R. (2018). Clinical and metabolic outcomes in pregnant women at risk for gestational diabetes mellitus supplemented with myo-inositol: a secondary analysis from 3 RCTs. American journal of obstetrics and gynecology, 219(3), 300-e1.

[xiv] Vitagliano, A., Saccone, G., Cosmi, E., Visentin, S., Dessole, F., Ambrosini, G., & Berghella, V. (2019). Inositol for the prevention of gestational diabetes: a systematic review and meta-analysis of randomized controlled trials. Archives of Gynecology and Obstetrics, 299(1), 55-68.

[xv] Esteghamati, A., Aryan, Z., Esteghamati, A. R., & Nakhjavani, M. (2015). Vitamin D deficiency is associated with insulin resistance in nondiabetics and reduced insulin production in type 2 diabetics. Hormone and Metabolic Research, 47(04), 273-279.

Marcotorchino, J., Gouranton, E., Romier, B., Tourniaire, F., Astier, J., Malezet, C., … & Landrier, J. F. (2012). Vitamin D reduces the inflammatory response and restores glucose uptake in adipocytes. Molecular nutrition & food research, 56(12), 1771-1782.

Norman, A. W., Frankel, J. B., Heldt, A. M., & Grodsky, G. M. (1980). Vitamin D deficiency inhibits pancreatic secretion of insulin. Science, 209(4458), 823-825.

[xvi] Bao, W., Song, Y., Bertrand, K. A., Tobias, D. K., Olsen, S. F., Chavarro, J. E., … & Zhang, C. (2018). Prepregnancy habitual intake of vitamin D from diet and supplements in relation to risk of gestational diabetes mellitus: A prospective cohort study: Journal of diabetes, 10(5), 373-379.

[xvii] Yin, W. J., Tao, R. X., Hu, H. L., Zhang, Y., Jiang, X. M., Zhang, M. X., … & Zhu, P. (2020). The association of vitamin D status and supplementation during pregnancy with gestational diabetes mellitus: a Chinese prospective birth cohort study. The American Journal of Clinical Nutrition, 111(1), 122-130.

[xviii] Ojo, O., Weldon, S. M., Thompson, T., & Vargo, E. J. (2019). The effect of vitamin d supplementation on glycaemic control in women with gestational diabetes mellitus: A systematic review and meta-analysis of randomised controlled trials. International journal of environmental research and public health, 16(10), 1716.

[xix] Soheilykhah, S., Mojibian, M., Moghadam, M. J., & Shojaoddiny-Ardekani, A. (2013). The effect of different doses of vitamin D supplementation on insulin resistance during pregnancy. Gynecological Endocrinology, 29(4), 396-399.

[xx] Baynes, H. W., Mideksa, S., & Ambachew, S. (2018). The role of polyunsaturated fatty acids (n-3 PUFAs) on the pancreatic β-cells and insulin action. Adipocyte, 7(2), 81-87.

[xxi] Jamilian, M., Samimi, M., Kolahdooz, F., Khalaji, F., Razavi, M., & Asemi, Z. (2016). Omega-3 fatty acid supplementation affects pregnancy outcomes in gestational diabetes: a randomized, double-blind, placebo-controlled trial. The Journal of Maternal-Fetal & Neonatal Medicine, 29(4), 669-675.

[xxii] Jamilian, M., Samimi, M., Ebrahimi, F. A., Hashemi, T., Taghizadeh, M., Razavi, M., … & Asemi, Z. (2017). The effects of vitamin D and omega-3 fatty acid co-supplementation on glycemic control and lipid concentrations in patients with gestational diabetes. Journal of Clinical Lipidology, 11(2), 459-468.