Clinical Review

How to improve outcomes in gestational diabetes— for mother and baby

OBG Manag. 2011 March;23(3):36-45

Early diagnosis, close monitoring, and aggressive management
may improve outcomes, for both patients, in pregnancies marked
by gestational diabetes mellitus

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IN THIS ARTICLE

Diagnosis has been simplified
Treatment should be aggressive
Continuous glucose monitoring may improve outcomes

References

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2. Shah BR, Retnakaran R, Booth GL. Increased risk of cardiovascular disease in young women following gestational diabetes mellitus. Diabetes Care. 2008;31(8):1668-1669.

3. Dabelea D, Knowler WC, Pettitt DJ. Effect of diabetes in pregnancy on offspring: follow-up research in the Pima Indians. J Matern Fetal Med. 2000;9(1):83-88.

4. Gunderson EP, Jacobs DR, Chiang V, et al. Childbearing is associated with higher incidence of the metabolic syndrome among women of reproductive age controlling for measurements before pregnancy: the CARDIA study. Am J Obstet Gynecol. 2009;201(2):177.e1-9.

5. van Hoorn J, Dekker G, Jeffries B. Gestational diabetes versus obesity as risk factors for pregnancy-induced hypertensive disorders and fetal macrosomia. Aust N Z J Obstet Gynaecol. 2002;42(1):29-34.

6. Torloni MR, Betrán AP, Horta BL, et al. Prepregnancy BMI and the risk of gestational diabetes: a systematic review of the literature with meta-analysis. Obes Rev. 2009;10(2):194-203.

7. Johns K, Olynik C, Mase R, Kreisman S, Tildesley H. Gestational diabetes mellitus outcome in 394 patients. J Obstet Gynaecol Can. 2006;28(2):122-127.

8. Jones CW. Gestational diabetes and its impact on the neonate. Neonatal Netw. 2001;20(6):17-23

9. De Luca AK, Nakazawa CY, Azevedo BC, Rudge MV, De Araujo Costa RA, Calderon IM. Influence of glycemic control on fetal lung maturity in gestations affected by diabetes or mild hyperglycemia. Acta Obstet Gynecol Scand. 2009;88(9):1036-1040.

10. Esakoff TF, Cheng YW, Sparks TN, Caughey AB. The association between birthweight 4000 g or greater and perinatal outcomes in patients with and without gestational diabetes mellitus. Am J Obstet Gynecol. 2009;200(6):672.-e1–4.

11. Vohr BR, Boney CM. Gestational diabetes: the forerunner for the development of maternal and childhood obesity and metabolic syndrome? J Matern Fetal Neonatal Med. 2008;21(3):149-157

12. ter Braak EW, Evers IM, Willem Erkelens D, Visser GH. Maternal hypoglycemia during pregnancy in type 1 diabetes: maternal and fetal consequences. Diabetes Metab Res Rev. 2002;18(2):96-105.

13. Reece EA. The fetal and maternal consequences of gestational diabetes mellitus. J Matern Fetal Neonatal Med. 2010;23(3):199-203.

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16. Metzger BE, Lowe LP, Dyer AR, et al. HAPO Study Cooperative Research Group. Hyperglycemia and adverse pregnancy outcomes. New Engl J Med. 2008;358(19):1991-2002.

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18. Bonomo M, Corica D, Mion E, et al. Evaluating the therapeutic approach in pregnancies complicated by borderline glucose intolerance: a randomized clinical trial. Diabet Med. 2005;22(11):1536-1541.

19. Landon MB, Spong CY, Thom E, et al. Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. A multicenter randomized trial of treatment for mild gestational diabetes. N Engl J Med. 2009;361(14):1339-1348.

20. 20Cypryk K, Kaminska P, Kosinski M, Pertynska-Marczewska M, Lewinski A. A comparison of the effectiveness tolerability and safety of high and low carbohydrate diets in women with gestational diabetes. Endokrynol Pol. 2007;58(4):314-319.

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22. Hod M, Damm P, Kaaja R, et al. Insulin Aspart Pregnancy Study Group. Fetal and perinatal outcomes in type 1 diabetes pregnancy: a randomized study comparing insulin aspart with human insulin in 322 subjects. Am J Obstet Gynecol. 2008;198(2):186-187.

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RELATED ARTICLE

Are oral hypoglycemic agents equivalent to insulin in the treatment of gestational diabetes?
Aaron B. Caughey, MD, PhD; (Examining the Evidence, March 2011)

Gestational diabetes mellitus (GDM) was once thought to be a mild condition that had few lasting consequences. Now, we know that it carries significant short- and long-term implications for women and their offspring. A growing body of evidence suggests that early detection and aggressive monitoring and management of GDM can greatly improve outcomes for pregnant women and their babies. This article outlines the parameters of this approach.

GDM increases maternal risks even after pregnancy

Even mild degrees of hyperglycemia during pregnancy can harm mother and baby. Hyperglycemia is associated with an elevated risk of hypertensive disorders during pregnancy, as well as preterm labor, cesarean delivery, and later metabolic disorders—but there is no obvious threshold of hyperglycemia at which these risks increase.¹

GDM is a strong predictor that a woman will later develop type 2 diabetes.² One study found that GDM increases that risk as much as sevenfold over a woman’s lifetime.³ GDM is also associated with an elevated risk of cardiovascular disease, particularly if the woman has a family history of type 2 diabetes.⁴

Obesity appears to worsen the consequences of GDM for women.⁵ A recent literature review found that the risk of GDM is positively associated with the prepregnancy body mass index (BMI).⁶

One of the most common and serious types of morbidity affecting infants born to women who have GDM is large size for gestational age, which imparts a significantly elevated risk of injury at the time of vaginal birth and increases the risk of trauma to the mother during cesarean delivery.

GDM is not benign in the fetus, either

Evidence is increasing that GDM raises the risk of adverse clinical consequences in the fetus. The two most frequent and serious types of morbidity affecting infants born to mothers who have GDM are:

large size for gestational age
respiratory distress syndrome.⁷

Infants who are large for gestational age (LGA) face a significantly elevated risk of injury at the time of vaginal birth, such as shoulder dystocia and newborn asphyxia.⁸ Cesarean delivery is the preferred route for the LGA infant, but it often increases the risk of trauma to the mother, compared with the vaginal route.⁸

Respiratory distress syndrome, common among premature infants, also affects many infants born to women who have GDM— even near-term infants—because hyperglycemia appears to delay fetal lung maturity.⁹

Recent studies indicate that exposure to maternal hyperglycemia also increases a child’s risk of long-term complications. Children born to mothers who have GDM have nearly twice the risk of childhood obesity and metabolic syndrome, compared with children born to mothers who do not have GDM.¹⁰ In addition, several studies have found that children born to obese mothers who have GDM are more likely to develop type 2 diabetes than are children of non-obese mothers without GDM.^3,11

Occasionally, infants of women who have GDM are born with hypoglycemia; this condition arises from an insulin surge in response to maternal hyperglycemia. In an infant, hypoglycemia can lead to seizures and death, and maternal hypoglycemia can cause neuro-psychological deficits in the infant.¹²

Other health problems related to GDM include jaundice and developmental delays in walking and other motor skills.¹³

Diagnosis has been simplified

The two-step, 100-g, 3-hour oral glucose tolerance test (OGTT) has been the gold standard for diagnosis of GDM in the United States for many years. However, this approach is expensive—rendering it impractical in some settings. Moreover, reproducibility is only approximately 78%.¹⁴

The World Health Organization recently reviewed evidence underlying various diagnostic techniques and recommended a one-step, 2-hour, 75-g OGTT for GDM.¹⁴ Another recent review of the literature on the various screening protocols underscores the validity of this approach.¹⁵

The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study of more than 23,000 nondiabetic women incorporated the 2-hour, 75-g OGTT.¹⁶ Investigators found that elevated glucose levels on this test are highly predictive of birth weight above the 90th percentile and a cord-blood serum C-peptide level above the 90th percentile. However, the test has weaker predictive value for primary cesarean delivery and clinical neonatal hypoglycemia.

Based on the work of HAPO, the American Diabetes Association (ADA) revised its guidelines for diabetes assessment and now recommends that physicians perform a 75-g OGTT at 24 to 28 weeks’ gestation, with plasma glucose measurement in the fasting state and at 1 and 2 hours. A single abnormal level merits a diagnosis of GDM in women not previously diagnosed with overt diabetes.¹⁷