August/September 2024 Issue
The Evolving Landscape of Gestational Diabetes Management
By Constance Brown-Riggs, MSEd, RDN, CDCES, CDN
Today’s Dietitian
Vol. 26 No. 7 P. 18
A Comprehensive Update of the Latest Advances in Technology, Pharmacology, and Lifestyle Modifications
The landscape of gestational diabetes mellitus (GDM) management is evolving. Advances in research, technology, and pharmacology are leading to more effective, patient-friendly approaches to managing GDM, signaling a future where the condition’s impact on maternal and neonatal health is significantly reduced.
This article highlights the latest updates and emerging treatments for GDM so registered dietitian nutritionists can provide up-to-date, evidence-based care and help improve patient outcomes.
Rising Rates
GDM is a growing concern in maternal health, marked by rising rates over recent years. The percentage of mothers giving birth who received a diagnosis of diabetes during pregnancy increased from 6% in 2016 to 8.3% in 2021.1 This upward trend was observed across all maternal age groups, with rates climbing consistently with advancing maternal age. In 2021, the rate for mothers aged 40 years and older reached 15.6%, nearly six times higher than the 2.7% rate for mothers under 20 years of age.1 Sue-Ellen Anderson-Haynes, MS, RDN, CDCES, LDN, CPT, a spokesperson for the Academy of Nutrition and Dietetics, says, “The increased rate of gestational diabetes can be attributed to the rising obesity rates, increased maternal age, multiple gestation, and social determinants of health such as access to medical care and healthy food.”
The health implications of GDM aren’t to be underestimated, as it poses significant risks to both mother and child. “Mothers with uncontrolled gestational diabetes are at increased risk for C-section delivery or difficult delivery, preeclampsia, and type 2 diabetes after delivery or later in life. Fetal complications include preterm birth, neonatal hypoglycemia, large-for-gestational-age (LGA) and type 2 diabetes and obesity in childhood,” Anderson-Haynes says.
The previous statistics underscore the need for greater awareness, early detection, and effective management strategies to mitigate the risks associated with GDM for both mothers and their babies.
Classification and Risk Factors
GDM is a condition characterized by glucose intolerance that is first recognized during pregnancy. GDM is classified in two categories: A1GDM and A2GDM.2 A1GDM refers to GDM that can be controlled with diet and exercise alone. In contrast, A2GDM is a more severe form that requires pharmacological interventions, such as insulin, to achieve adequate glycemic control.2 Understanding these classifications is critical for tailoring appropriate treatment plans to ensure the health and well-being of mother and baby.
Several risk factors predispose women to developing GDM. These include advanced maternal age, obesity linked to higher BMI, family history of diabetes (especially type 2), prior history of GDM, susceptibility based on ethnicity (Hispanic, African American, Native American, Asian, and Pacific Islander), and the presence of polycystic ovary syndrome.2
Moreover, lifestyle habits such as poor diet, lack of physical activity, and excessive weight gain during pregnancy can further exacerbate the risk of developing GDM.2
Screening and Diagnosing
Screening for GDM typically occurs between 24 and 28 weeks of gestation, though screening may be done earlier for high-risk individuals. The standard screening process involves one of two strategies: the “one-step” 75-g oral glucose tolerance test (OGTT) or the “two-step” approach with a 50-g (nonfasting) glucose challenge test followed by a 100-g OGTT for those who screen positive.3 Alyce Thomas, RDN, FAND, author of the Health Professional’s Guide to Nutrition, Diabetes, and Pregnancy and a member of the 2013 National Institutes of Health consensus development panel that was convened to consider diagnostic criteria for diagnosing GDM, emphasizes the complexity and lack of consensus in screening methods. She explains, “When I was on the panel, we didn’t find evidence that you should use one strategy over the other.” This perspective aligns with the American Diabetes Association (ADA) 2024 Standards, which continue to see no consensus among expert groups regarding optimal strategies for diagnosing GDM.3
GDM is diagnosed based on the results of the OGTT. A 75-g OGTT is conducted in the one-step strategy. Plasma glucose levels, including fasting, at one and two hours post-OGTT, are measured after an overnight fast of at least eight hours. Diagnosis of GDM is confirmed if any of the following thresholds are met: fasting at 92 mg/dL, one hour at 180 mg/dL, or two hours at 153 mg/dL.3 Conversely, the two-step strategy involves an initial 50-g glucose loading test with plasma glucose measured at one hour. If the one-hour glucose level is equal to or over 130, 135, or 140 mg/dL, a 100-g three-hour OGTT is performed while fasting.3 Diagnosis under this strategy requires meeting or exceeding two of the following values: first hour more than 180 mg/dL, second hour more than 155 mg/dL, and third hour more than 140 mg/dL.3
Traditional Management
The treatment landscape for GDM is enhanced by emerging research, offering promising new approaches. Traditional management strategies primarily focus on lifestyle modifications and medical nutritional therapy, which remain foundational. These strategies include dietary changes, physical activity, and blood glucose monitoring.
Dietary Changes
This approach emphasizes balanced meals with controlled carbohydrate intake. Alefiya Faizullabhoy, MBA, MS, RD, CDCES, CDN, FAND, manager of nutrition and dietetics for the Diabetes in Pregnancy Program at Northwell Health in New Hyde Park, New York, uses the plate method to help patients control portions and carbohydrate intake. Faizullabhoy tells her patients to “Aim for a healthful plate with 50% of the plate as nonstarchy vegetables, 25% of it lean or plant-based protein, and 25% as starch choices.” Individual responses and tolerance may vary and require further personalization of recommendations.
Physical Activity
Regular exercise is encouraged for improving insulin sensitivity. “Studies reveal that pregnant participants who exercise less are likely to develop LGA infants. Likewise, a 2017 study in the Journal of Diabetes showed women with GDM achieved a reduction in fasting blood glucose concentration with weekly supervised exercise compared with usual prenatal care,” Anderson-Haynes says.4
Blood Glucose Monitoring
Frequent self-monitoring is encouraged to maintain optimal glucose levels. The ADA recommends monitoring fasting, before-meal, and after-meal blood glucose levels in pregnant individuals with diabetes to maintain ideal glucose levels. This typically takes place with a fingerstick glucometer. The target glucose levels are a fasting plasma glucose below 95 mg/dL and postmeal glucose below 140 mg/dL at one hour or below 120 mg/dL at two hours.3
Evolving Approaches to Treatment
Emerging solutions for GDM management and treatment may provide valuable support for both the care team and patients. Opportunities for continuous glucose monitoring, understanding the latest research on first-line pharmacological therapies, and precision medicine are some areas of interest.
Continuous Glucose Monitoring
Recent advances in research bring a promising outlook for utilizing continuous glucose monitors (CGMs) in GDM. Studies like the FLAMINGO study have demonstrated the advantages of CGMs in monitoring fasting glucose levels and postprandial glucose responses in pregnant individuals with diabetes.5 The study findings highlight the positive impact of flash glucose monitoring on managing GDM by improving blood glucose control and dietary habits and reducing the incidence of fetal macrosomia (birth weight exceeding 4000 g) in patients with GDM.5
Anderson-Haynes highlights findings from the CONCEPTT Trial, which investigated the use of CGMs in pregnant women with type 1 diabetes.6 The study revealed that CGMs offer benefits to pregnant women with type 1 diabetes by enhancing metrics such as maternal blood glucose levels, reducing the occurrence of LGA births, and minimizing neonatal hypoglycemia—all of which are challenges observed in women with uncontrolled GDM.6 Anderson-Haynes emphasizes that while the results of the CONCEPTT Trial show promise for GDM management, there is currently insufficient data to determine the optimal time in range for women with this condition.
Diagnosing GDM early in pregnancy can yield numerous benefits, including improving maternal and fetal health outcomes while potentially reducing the long-term risks associated with GDM. A study by Durnwald and colleagues, published in Diabetes Care, revealed that CGM patterns in early pregnancy can detect blood glucose issues before the usual OGTT screening.7 The study also demonstrated that early detection and management of GDM resulted in decreased rates of adverse pregnancy outcomes and improved maternal health markers.
Considering the benefits of early detection of GDM and the findings from Durnwald’s study, it’s evident that timely identification can significantly improve maternal and fetal health outcomes. However, concerns about the psychological impact and burden of CGM use among pregnant individuals are also noteworthy. Heather I. Levin, MD, FACOG, an assistant professor of maternal fetal medicine in the department of obstetrics and gynecology at Northwell Health in New York, reflects on this dual perspective, highlighting both the potential benefits of CGM use in understanding the impact of dietary choices on blood sugar levels and the challenges monitoring may pose in terms of patient experience and management.
Faizullabhoy observes that with the approval of devices like the DEXCOM G7 and FreeStyle Libre 2 and 3, many patients view CGMs as a viable alternative to self-monitoring blood glucose with a finger-stick glucometer. “While ACOG [American College of Obstetricians and Gynecologists] and the ADA recommend self-monitoring of blood glucose as the standard of care, up to six times a day to gather data, continuous glucose monitoring offers distinct advantages such as pattern management insight and data trend analysis. As technological advancements progress, there is a growing likelihood of increased adoption and recommendations for using CGMs in managing gestational diabetes,” Faizullabhoy says.
The expansion of CGM usage to include GDM suggests a growing recognition of its value in ensuring optimal glucose control during pregnancy. This trend aligns with the broader integration of CGM systems in diabetes management, reflecting a positive trajectory toward enhancing monitoring accessibility and care for pregnant individuals with diabetes.
Metformin as First-Line Therapy
The ADA recommends insulin as the primary treatment for hyperglycemia in GDM, advising against using metformin initially due to placental transfer. However, a recent JAMA study suggests that starting metformin when GDM is diagnosed was associated with improved blood glucose and reduced weight gain.8
Levin, who does not use metformin as first-line therapy, except in cases of patients refusing insulin, says, “I do appreciate it as an adjunct to insulin, and the weight gain benefits. There are many patients who would prefer an oral medication to an injectable medication, but, in my opinion, there is insufficient data to support metformin as a first-line therapy.” Moreover, Levin doesn’t believe metformin will become a first-line therapy for GDM because currently, the ADA, ACOG, and The Society for Maternal-Fetal Medicine don’t support metformin as first-line therapy.
There is emerging evidence in support of metformin’s use as first-line therapy. According to a June 2, 2024, press release from the Endocrine Society, a recent study presented at ENDO 2024 suggests that metformin is a safe option for managing diabetes during pregnancy. The study, which analyzed data from 10,117 children-mother pairs across seven study cohorts, concluded that metformin is as safe as insulin for lowering blood glucose levels during pregnancy, with no observed long-term adverse effects on either the children or mothers for up to 11 years after childbirth. This study sheds light on metformin’s safety and effectiveness in pregnancy, offering an alternative to traditional insulin therapy.
Precision Medicine
Precision medicine, also known as personalized medicine, is advancing as a tool in GDM management. A 2024 study in Nature conducted a systematic review of precision stratification of prognostic risk factors in GDM.9 The research focused on factors impacting maternal and offspring outcomes, highlighting the significance of personalized approaches tailored to individual risk factors for improved outcomes. The study indicates that precision medicine shows promise in enhancing diagnosis, treatment, and prevention strategies for GDM to better the long-term health of those diagnosed with GDM.
Research on the gut microbiota and precision medicine is rapidly evolving, offering another promising avenue for GDM management. A recent meta-analysis of randomized controlled trials (RCTs) published in Clinical Nutrition examined the effects of specific probiotic strains, such as Lactobacillus and Bifidobacterium, on metabolic outcomes in GDM patients. The findings suggest that integrating probiotics into precision medicine strategies could be beneficial. Probiotics were linked to significant improvements in fasting blood glucose levels, insulin levels, insulin resistance, and insulin sensitivity. Moreover, the effects of the probiotics were more pronounced in individuals with higher baseline BMI and glucose levels, suggesting that tailored probiotic interventions based on individual patient profiles—a core concept of precision medicine—could be more effective.10 However, the researchers recommend more randomized controlled trials to solidify the findings and refine the precision medicine approach.
“All of these developments are exciting and likely will change the landscape in which we practice,” Faizullabhoy says. “However, a word of caution is necessary that these advances assist and not impede the person with GDM. The psychological impact of these advances must be weighed as well to avoid adding undue stress for the pregnant person,” Faizullabhoy says.
While continuous glucose monitoring and new pharmacologic treatments offer advanced options for managing GDM, they complement rather than replace traditional methods. Lifestyle modifications and medical and nutritional therapy continue to be crucial for initial management and are often sufficient for maintaining glycemic control in many cases.
However, for those requiring further intervention, the integration of CGM technology and precision pharmacotherapy represents a significant step forward. These modern approaches allow for tailored treatment plans that can adapt to the unique needs of each patient, potentially reducing the risk of complications and improving overall pregnancy outcomes.
Putting It Into Practice
As an RD and Certified Diabetes Care and Education Specialist, counseling patients with GDM involves a comprehensive approach that addresses their unique nutritional, medical, and lifestyle needs. Below is a breakdown of strategies to effectively counsel patients.
Stay Informed and Educated
Staying updated on the latest research ensures you know the newest findings and best practices in GDM management. Set up alerts for new publications on GDM. Attend conferences like the ADA Scientific Sessions or webinars from professional organizations like the Academy of Nutrition and Dietetics or the Association of Diabetes Care and Education Specialists.
Interdisciplinary Collaboration
“Work and communicate with an interdisciplinary team that includes important team players such as a Certified Diabetes Care and Education Specialist, OB/GYN, maternal and fetal medicine specialist, and endocrinologist,” Anderson-Haynes says. Collaborative care ensures that all aspects of the patient’s health are addressed and integrated into a cohesive treatment plan.
Patient-Centered Care
Thomas underscores the importance of recognizing each patient’s individuality, advocating for honesty, open communication, and active listening to build trust and find solutions. She highlights the need to address real life challenges, such as limited food resources, with practical, tailored solutions. Patient-centered care is central to her approach, ensuring patients feel understood and supported by showing genuine interest in their lives beyond their health conditions. Thomas shared a story about a patient facing severe financial difficulties, with only eight items left in her refrigerator until the next paycheck. Instead of focusing on ideal dietary guidelines, they devised a meal plan using those eight items to last the week.
Many mothers feel guilty when diagnosed with GDM. They often worry that they have done something to cause the condition. Understanding the role of insulin resistance and hormonal changes in GDM can help alleviate these feelings of guilt, as it clarifies that the condition results from physiological changes during pregnancy rather than personal failings.
Faizullabhoy stresses that counseling should cover how insulin resistance increases during pregnancy and the importance of adopting healthy lifestyle behaviors, which can lead to lifelong habits. “It’s also important to explain that GDM has both maternal and fetal implications, which include but aren’t limited to type 2 diabetes, obesity, neonatal jaundice, hypoglycemia, and large for gestational age at birth,” Faizullabhoy says.
Postpartum Care
Faizullabhoy emphasizes the essential role RDNs play in helping clients sustain healthful behaviors beyond pregnancy. She highlights the challenges of the postpartum period—often called the fourth trimester—and underscores the importance of empowering individuals to maintain positive changes. “Providing the base for continued and ongoing positive behaviors can elicit changes that positively impact the person. Working with the person for joint SMART goals can set the tone for sustainable lifestyle changes.”
Final Thoughts
GDM presents a significant challenge in maternal-fetal medicine, with its rising prevalence necessitating ongoing advancements in management strategies. From traditional lifestyle modifications to cutting-edge technologies like continuous glucose monitoring and precision pharmacotherapy and nutrition therapy, the evolving landscape of GDM treatment offers hope for improved outcomes and reduced complications. By prioritizing effective management and staying abreast of the latest research, health care providers can help ensure healthier pregnancies and long-term well-being for women and their families.
— Constance Brown-Riggs, MSEd, RDN, CDCES, CDN, is a national speaker and
author of the award-winning books Living Well With Diabetes 14 Day Devotional
and Diabetes Guide to Enjoying Foods of the World. Learn more about her at www.ConstanceBrownRiggs.com.
References
1. QuickStats: percentage of mothers with gestational diabetes, by maternal age — National Vital Statistics System, United States, 2016 and 2021. MMWR Morb Mortal Wkly Rep; 2023;72(1):16.
2. Quintanilla Rodriguez BS, Mahdy H. Gestational diabetes. In: StatPearls. Treasure Island, FL: StatPearls Publishing; 2023. https://www.ncbi.nlm.nih.gov/books/NBK545196/#. Accessed June 4, 2024.
3. American Diabetes Association Professional Practice Committee. 2. Diagnosis and classification of diabetes: Standards of Care in Diabetes—2024. Diabetes Care. 2024;47(Suppl 1):S20-S42.
4. Bgeginski R, Ribeiro PAB, Mottola MF, Ramos JGL. Effects of weekly supervised exercise or physical activity counseling on fasting blood glucose in women diagnosed with gestational diabetes mellitus: a systematic review and meta-analysis of randomized trials. J Diabetes. 2017;9(11):1023-1032.
5. Majewska, A, Stanirowski, PJ, Tatur, J, et al. Flash glucose monitoring in gestational diabetes mellitus (FLAMINGO): a randomised controlled trial. Acta Diabetol. 2023;60(9):1171-1177.
6. Feig DS, Donovan LE, Corcoy R, et al. Continuous glucose monitoring in pregnant women with type 1 diabetes (CONCEPTT): a multicentre international randomised controlled trial. Lancet. 2017;390(10110):2347-2359.
7. Durnwald C, Beck R, Li Z, et al. 173-OR: CGM-measured differences in pregnancies with vs. without gestational diabetes (GDM) and adverse perinatal outcomes (APO). Diabetes. 2023;72(Supplement_1):173-OR.
8. Dunne F, Newman C, Alvarez-Iglesias A, et al. Early metformin in gestational diabetes: a randomized clinical trial. JAMA. 2023;330(16):1547-1556.
9. Semnani-Azad Z, Gaillard R, Hughes AE, et al. Precision stratification of prognostic risk factors associated with outcomes in gestational diabetes mellitus: a systematic review. Commun Med (Lond). 2024;4(1):9.
10. Lan X, Li B, Zhao J, et al. Probiotic intervention improves metabolic outcomes in gestational diabetes mellitus: a meta-analysis of randomized controlled trials. Clin Nutr. 2024;43(7):1683-1695.