Correspondence

Gestational Diabetes

N Engl J Med 2000; 342:896-897March 23, 2000

Article

To the Editor:

Screening for and treatment of gestational diabetes mellitus remain matters of considerable debate, yet Kjos and Buchanan convey no sense of this controversy in their recent review (Dec. 2 issue).1 That some pregnancies involve more marked alterations in glucose metabolism than others is certain. Whether the detection and treatment of these outlier cases results in improved maternal or neonatal outcomes is less clear.

Kjos and Buchanan provide no outcome data from appropriately designed trials indicating that there is a benefit to intervention in pregnancies complicated by gestational diabetes. To be fair, they cannot discuss such data because the necessary trials have not been performed. On the other hand, the authors do describe research indicating that the diagnosis of gestational diabetes by itself increases a woman's risk of cesarean delivery and that aggressive treatment of gestational diabetes is associated with an increased risk of delivering an infant who is small for gestational age.

Recognizing the limits of the data, the U.S. Preventive Services Task Force concludes that “there is insufficient evidence to recommend for or against universal screening for gestational diabetes mellitus.”2 The Canadian Task Force on the Periodic Health Examination goes further, stating that “screening for gestational diabetes cannot be recommended on the basis of available evidence.”3 The Cochrane Collaboration is even more cautionary, arguing that “until the risk of minor elevations of glucose during pregnancy has been established in appropriately conducted trials, it is unethical to involve pregnant women in interventions based on this diagnosis.”4 It would be better to highlight the uncertainty reflected in these statements rather than simply to reiterate accepted dogma.

Jeffrey L. Ecker, M.D.
Maria A. Mascola, M.D., M.P.H.
Laura E. Riley, M.D.
Massachusetts General Hospital, Boston, MA 02114

4 References

1. 1

   Kjos SL, Buchanan TA. Gestational diabetes mellitus. N Engl J Med 1999;341:1749-1756
   Full Text | Web of Science | Medline

2. 2

   Preventive Services Task Force. Guide to clinical preventive services: report of the U.S. Preventive Services Task Force. Alexandria, Va.: International Medical Publications, 1996:193-208.
   

3. 3

   Canadian Task Force on the Periodic Health Examination. Canadian guide to clinical preventive health care. Ottawa, Ont.: Canadian Communication Group, 1994;16-23:601-9.
   

4. 4

   Walkinshaw SA. Diet + insulin vs diet alone for `gestational diabetes.' In: Enkin MW, Kierse MJNC, Renfrew MJ, Neilson JP, eds. Pregnancy and childbirth module. Cochrane database of systematic reviews. No. 06650. April 20, 1993.
   

Author/Editor Response

The authors reply:

To the Editor: We agree with Ecker et al. that the detection and treatment of gestational diabetes mellitus are matters of considerable controversy. We began our review with an acknowledgment of that controversy, followed by statements about the risk of not diagnosing anyone and the risk of aggressively treating everyone with asymptomatic hyperglycemia during pregnancy. Rather than discussing these two extreme approaches, we focused on a middle ground where we believe the most logical approach to gestational diabetes lies.

In favor of diagnosing and treating gestational diabetes, we presented evidence from a blinded study1 that small increases in maternal glycemia are associated with increases in perinatal risk. This evidence addresses the concern of the Cochrane Collaboration, as cited by Ecker et al. We also presented evidence, including results from randomized studies, that interventions to decrease maternal glycemia reduce the risk of some of the perinatal complications of gestational diabetes. In favor of not treating everyone with gestational diabetes aggressively, we presented evidence that only a minority of cases involve perinatal complications and that the diagnosis of gestational diabetes can lead to iatrogenic complications (e.g., increased rates of cesarean section2).

Although there are no data from multicenter, double-blind, controlled trials designed to address all management issues, the sum of the available evidence provides a sound rationale for screening women with asymptomatic hyperglycemia during pregnancy. The evidence also provides a rationale for discriminating between women who will have perinatal complications and those who will not. The continuous relation between maternal glycemia and risks to the fetus indicates that measurement of maternal glucose may be an inefficient way to discriminate between these two groups of women. Nonetheless, we presented glycemia-based approaches to management because they are common in clinical practice and because they have been estimated to be cost effective.3 We also presented approaches based on assessments of the fetus because they allow more efficient discrimination between no-risk and at-risk pregnancies.4

If unequivocal information about optimal detection and management of gestational diabetes were available, recommendations for care would be straightforward. In the absence of such information, we presented a rational approach for detection and management based on existing information and superimposed on a background of acknowledged controversy. Our presentation was reasonably balanced and was much more than a reiteration of dogma. We hope that it will prove useful to practitioners who are faced with difficult management decisions on a daily basis.

Siri L. Kjos, M.D.
Thomas A. Buchanan, M.D.
University of Southern California School of Medicine, Los Angeles, CA 90089-9317

4 References

1. 1

   Sermer M, Naylor CD, Gare DJ, et al. Impact of increasing carbohydrate intolerance on maternal-fetal outcomes in 3637 women without gestational diabetes. Am J Obstet Gynecol 1995;173:146-156
   CrossRef | Web of Science | Medline

2. 2

   Naylor CD, Sermer M, Chen E, Sykora K. Cesarean delivery in relation to birth weight and gestational glucose tolerance: pathophysiology or practice style? JAMA 1996;265:1165-1170
   CrossRef | Web of Science

3. 3

   Kitzmiller JL, Elixhauser A, Carr S, et al. Assessment of costs and benefits of management of gestational diabetes mellitus. Diabetes Care 1998;21:Suppl 2:B123-B130
   Web of Science | Medline

4. 4

   Buchanan TA, Kjos SL, Montoro MN, et al. Use of fetal ultrasound to select metabolic therapy for pregnancies complicated by mild gestational diabetes. Diabetes Care 1994;17:275-283
   CrossRef | Web of Science | Medline

Citing Articles (2)

Citing Articles

1. 1

   Ugo Covani, Simone Marconcini, Giacomo Derchi, Antonio Barone, Luca Giacomelli. (2009) Relationship Between Human Periodontitis and Type 2 Diabetes at a Genomic Level: A Data-Mining Study. Journal of Periodontology 80:8, 1265-1273
   CrossRef

2. 2

   S. Bjelland, P. Bray, N. Gupta, R. Hirsch. (2002) Dentists, Diabetes and Periodontitis. Australian Dental Journal 47:3, 202-207
   CrossRef