Elsevier

The Lancet

Volume 373, Issue 9677, 23–29 May 2009, Pages 1773-1779
The Lancet

Articles
Type 2 diabetes mellitus after gestational diabetes: a systematic review and meta-analysis

https://doi.org/10.1016/S0140-6736(09)60731-5Get rights and content

Summary

Background

Women with gestational diabetes are at increased risk of developing type 2 diabetes, but the risk and time of onset have not been fully quantified. We therefore did a comprehensive systematic review and meta-analysis to assess the strength of association between these conditions and the effect of factors that might modify the risk.

Methods

We identified cohort studies in which women who had developed type 2 diabetes after gestational diabetes were followed up between Jan 1, 1960, and Jan 31, 2009, from Embase and Medline. 205 relevant reports were hand searched. We selected 20 studies that included 675 455 women and 10 859 type 2 diabetic events. We calculated and pooled unadjusted relative risks (RRs) with 95% CIs for each study using a random-effects model. Subgroups analysed were the number of cases of type 2 diabetes, ethnic origin, duration of follow-up, maternal age, body-mass index, and diagnostic criteria.

Findings

Women with gestational diabetes had an increased risk of developing type 2 diabetes compared with those who had a normoglycaemic pregnancy (RR 7·43, 95% CI 4·79–11·51). Although the largest study (659 164 women; 9502 cases of type 2 diabetes) had the largest RR (12·6, 95% CI 12·15–13·19), RRs were generally consistent among the subgroups assessed.

Interpretation

Increased awareness of the magnitude and timing of the risk of type 2 diabetes after gestational diabetes among patients and clinicians could provide an opportunity to test and use dietary, lifestyle, and pharmacological interventions that might prevent or delay the onset of type 2 diabetes in affected women.

Funding

None.

Introduction

Gestational diabetes mellitus is defined as glucose intolerance that is first detected during pregnancy.1 In the USA, this condition affects 135 000 pregnancies (3–5% of all pregnancies) per year.2, 3 Shortly after delivery, glucose homoeostasis is restored to non-pregnancy levels, but affected women remain at high risk of developing type 2 diabetes mellitus in the future.4, 5

For any population and ethnic group, the risk of gestational diabetes indicates the underlying frequency of type 2 diabetes.2, 6 The incidences of gestational diabetes and type 2 diabetes are rising throughout the world, with huge health-care and economic costs.6, 7 Diabetes predisposes individuals to cardiovascular, renal, and retinal diseases, costing US$91·8 billion per year in the USA.8

Women who have had gestational diabetes are advised to have their glucose tolerance assessed 6 weeks after delivery.9 However, low rates of attendance at the 6-week follow-up10, 11 suggest that health-care professionals, women with gestational diabetes, or both, do not realise the importance of this disorder as an early warning sign of the susceptibility to develop type 2 diabetes in the future; therefore an opportunity to promote health and prevent disease is missed. Moreover, no consensus exists on how and whether mothers should continue to be monitored after this period.

The association between gestational diabetes and type 2 diabetes mellitus has implications for the elucidation of the causes of these disorders, and for the prediction and possible prevention or delay of the development of type 2 diabetes in women. We therefore did a comprehensive systematic review and meta-analysis to quantify the overall risk of women with gestational diabetes mellitus developing type 2 diabetes mellitus, and to assess the effect of factors that might modify this risk.

Section snippets

Search strategy and selection criteria

We did an electronic search of Embase from 1974 to Jan 31, 2009, and Medline from 1960 to Jan 31, 2009, without language restrictions. Search term combinations were “gestational diabetes”, “diabetic pregnancy”, “diabetes mellitus”, “type 2 diabetes mellitus”, “NIDDM”, and “non-insulin dependent diabetes mellitus”. All reference lists from the main reports and relevant reviews were hand searched for additional eligible studies.

We identified retrospective and prospective cohort studies, reported

Results

Figure 1 shows the study selection process (reasons for exclusion are listed in webappendix pp 1–13). 48 of 68 full-text reports meeting all the inclusion criteria were subsequently excluded because of the absence of an appropriate control or reference population. The 20 remaining studies (table),5, 15, 16, 17, 18, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 contributed 675 455 women with type 2 diabetes to the meta-analysis, and 31 867 of these had previous pregnancies affected

Discussion

Women who have had gestational diabetes have at least a seven-fold increased risk of developing type 2 diabetes mellitus in the future compared with those who have had a normoglycaemic pregnancy. The strength of the association between gestational diabetes and type 2 diabetes, and the knowledge that many of the risk factors are the same (ie, a family history of diabetes, raised body-mass index, increased age, and Asian and black ethnic origin), suggest that the two disorders might have an

References (56)

  • A Ben Haroush et al.

    Epidemiology of gestational diabetes mellitus and its association with type 2 diabetes

    Diabet Med

    (2004)
  • National diabetes fact sheet: general information and national estimates on diabetes in the United States, 2007

    (2008)
  • C Kim et al.

    Gestational diabetes and the incidence of type 2 diabetes

    Diabetes Care

    (2002)
  • IY Järvelä et al.

    Gestational diabetes identifies women at risk for permanent type 1 and type 2 diabetes in fertile age. Predictive role of auto-antibodies

    Diabetes Care

    (2006)
  • Economic costs of diabetes in the US in 2002

    Diabetes Care

    (2003)
  • Report of the expert committee on the diagnosis and classification of diabetes mellitus

    Diabetes Care

    (1997)
  • C Kim et al.

    Risk perception for diabetes among women with histories of gestational diabetes mellitus

    Diabetes Care

    (2007)
  • C Kim et al.

    Missed opportunities for type 2 diabetes mellitus screening among women with a history of gestational diabetes mellitus

    Am J Public Health

    (2006)
  • Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance

    Diabetes

    (1979)
  • Diabetes Mellitus: report of a WHO study group. Technical report series, number 727

    (1985)
  • Expert committee on the diagnosis and classification of diabetes mellitus: report of the expert committee on the diagnosis and classification of diabetes mellitus

    Diabetes Care

    (1997)
  • D Feig et al.

    Risk of development of diabetes mellitus after a diagnosis of gestational diabetes

    CMAJ

    (2008)
  • DF Stroup et al.

    (MOOSE group) Meta-analysis of observational studies in epidemiology, a proposal for reporting

    JAMA

    (2000)
  • Undertaking Systematic reviews of research on effectiveness: CRD's guidance for those carrying out or commissioning reviews. Report number 4

    (2001)
  • E Madarász et al.

    Metabolic syndrome after pregnancy complicated with gestational diabetes: four-year follow-up

    Orv Hetil

    (2008)
  • EP Gunderson et al.

    A 20-year prospective study of childbearing and incidence of diabetes in young women, controlling for glycaemia before conception. The Coronary Artery Risk Development in Young Adults (CARDIA) study

    Diabetes

    (2007)
  • A Vambergue et al.

    Increasing incidence of abnormal glucose tolerance in women with prior abnormal glucose tolerance during pregnancy: DIAGEST 2 study

    Diabet Med

    (2008)
  • AJ Lee et al.

    Gestational diabetes mellitus: Clinical predictors and long-term risk of developing type 2 diabetes

    Diabetes Care

    (2007)
  • Cited by (2563)

    View all citing articles on Scopus
    View full text