Prevention, Detection and Management of Gestational Diabetes

Gestational Diabetes Mellitus (GDM) is defined as high blood sugar (hyperglycemia) or glucose intolerance that comes on or is first recognized during pregnancy1. GDM is becoming an increasing health problem worldwide and one of the most common complications of pregnancy. In Canada, GDM is now more common than previous estimates. According to the Canadian Diabetes Association, the incidence of GDM ranges from 3.7% in non-Aboriginal women to 8–18% in Aboriginal women1. While a review sponsored by the Society of Obstetricians and Gynecologists of Canada could not conclusively support universal screening for all women2, the Canadian Diabetes Association 2008 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada recommends that all pregnant women be screened for GDM between weeks 24-28 of pregnancy using the gestational diabetes screen1. This test is a 2-phase blood test drawn 1 hour apart before and after the intake of a 50-gram glucose sample. If the blood glucose reading is between 7.8mmol/L and 10.3mmol/L, an oral glucose tolerance test should be done to confirm the diagnosis. If blood glucose is found to be above 10.3mmol/L during a gestational diabetes screen, a diagnosis of GDM is made and an oral glucose tolerance test is not required3. In women with multiple risk factors, screening should take place earlier during the first trimester and be repeated in subsequent trimesters regardless of previous negative results.  
Risk factors that put expectant mothers at increased risk of developing GDM include (1,4):

• previous diagnosis of GDM or delivery of a baby larger than 9lbs
• women of Aboriginal, Hispanic, South Asian, Asian and African descent
• being 35 years of age or older
• being obese (BMI of 30 kg/m2 or higher)
• medical history that includes: elevated blood pressure, polycystic ovary syndrome (PCOS), acanthosis nigricans (a skin disorder characterized by the appearance of darkened patches of skin)
• use of corticosteroids
• Impact of GDM

The early and accurate diagnosis of GDM is important because of the impact GDM can have on both mother and baby1,5. A pregnant mother’s elevated blood glucose levels can cause excess glucose to be passed on to the developing baby via the placenta. This puts the growing baby at risk of gaining excess weight, a condition termed “macrosomia.” Often such babies are born with birth weights in excess of 9lbs. The risks associated with macrosomia include complications during delivery such as slowed labour, increased risk of caesarian section and increased risk of injury to both mother and child. Elevated blood glucose in a baby in utero will also cause responsive hyperinsulinemia (increase in insulin production) in the baby. Such spikes in insulin put the baby at risk of hypoglycemia (dangerously low blood sugar levels) upon delivery.  Studies also show that macrosomic babies or babies born to mothers with GDM are more susceptible later in life to obesity, insulin resistance, glucose intolerance, cardiovascular disease and metabolic syndrome6.
Management of GDM
It is important to note that with early detection, GDM can be managed and risks to mother and baby can be minimized or prevented5. Management includes frequent visits with members of an expectant mom’s health care team and regular testing of blood pressure, urine for glucose and ketones, dietary counselling and exercise monitoring. If GDM cannot be managed by diet and lifestyle within several weeks, insulin therapy may be indicated1,3. While 85% of women with GDM will return to normal glucose tolerance 8 weeks postpartum, those with persisting impaired glucose tolerance are at particularly high risk of developing Type 2 diabetes. For this reason, the World Health Organization recommends GDM mothers be screened 6 weeks post delivery with an Oral Glucose Tolerance Test for continued signs of blood sugar dysregulation and annually thereafter. In Australia, a study coined the Australian Carbohydrate Intolerance Study in Pregnant Women (ACHOIS), concluded that a multidisciplinary care approach; something more than “routine antenatal care,” is required for optimal outcomes in this patient group7. Working with a naturopathic doctor can ensure that routine diagnostic testing is done while the necessary attention to nutrition and lifestyle are carried out. Naturopathic therapies are highly effective in the management of type 2 diabetes, and GDM is no exception. Finally, knowing that an ounce of prevention is worth a pound of cure, ensuring healthy eating habits and maintaining a healthy weight can ensure optimal blood sugar control is present from conception to term and beyond5.  Several tips that apply to all women in ensuring optimal nutritional intake and blood sugar regulation are as follows:

• eat a well balanced whole foods diet that includes low to moderate glycemic index foods
• eat small frequent meals & snacks spread out throughout the day rather than large meals and no snacks
• avoid refined and processed foods high in sugar and fat
• monitor blood pressure, blood glucose and urine as appropriate
• maintain a healthy weight preconception and during pregnancy
• active women should maintain a level of physical activity they are comfortable with (inactive women should incorporate light exercise or walking under the care of their health care practitioner)
• manage stress and take time for oneself

In preparing for pregnancy and during pregnancy, every family wants to take the steps necessary to ensure optimal health. The risks and complications of Gestational Diabetes Mellitus can be prevented and treated with the care of a comprehensive health care team, the right information and empowerment to make healthy lifestyle choices.
References:
1. Canadian Diabetes Association. Gestational diabetes: Preventing complications in pregnancy www.diabetes.ca/about-diabetes/what/gestational/   Accessed August 16, 2009.
2. Berger et al. Screening for gestational diabetes mellitus. J Obstet Gynaecol Can. 2002 Nov;24(11):894-912.
3. Women’s College Hospital. Women’s Health Matters.  Diabetes Health Centre Pregnancy www.womenshealthmatters.ca/Centres/diabetes/pregnancy/gestational.html  Accessed August 16, 2009.
4. Massion et al. Screening for gestational diabetes in a high risk population. J Fam Pract. 1987 Dec;25(6):569-75.
5. The diabetic pregnant woman. Ann Endocrinol (Paris) 2003 Jun;64(3 Suppl):S7-11.
6. Boney et al. Metabolic syndrome in childhood: association with birth weight, maternal obesity, and gestational diabetes mellitus Pediatrics. 2005 Mar;115(3):e290-6.
7. HD McIntyre et al. Gestational diabetes mellitus: from consensus to action on screening and treatment MJA 2005; 183 (6): 288-289.