Gestational diabetes and the incidence of type 2 diabetes: a systematic review.
OBJECTIVE
To examine factors associated with variation in the risk for type 2 diabetes in women with prior gestational diabetes mellitus (GDM).


METHODS
We conducted a systematic literature review of articles published between January 1965 and August 2001, in which subjects underwent testing for GDM and then testing for type 2 diabetes after delivery. We abstracted diagnostic criteria for GDM and type 2 diabetes, cumulative incidence of type 2 diabetes, and factors that predicted incidence of type 2 diabetes.


RESULTS
A total of 28 studies were examined. After the index pregnancy, the cumulative incidence of diabetes ranged from 2.6% to over 70% in studies that examined women 6 weeks postpartum to 28 years postpartum. Differences in rates of progression between ethnic groups was reduced by adjustment for various lengths of follow-up and testing rates, so that women appeared to progress to type 2 diabetes at similar rates after a diagnosis of GDM. Cumulative incidence of type 2 diabetes increased markedly in the first 5 years after delivery and appeared to plateau after 10 years. An elevated fasting glucose level during pregnancy was the risk factor most commonly associated with future risk of type 2 diabetes.


CONCLUSIONS
Conversion of GDM to type 2 diabetes varies with the length of follow-up and cohort retention. Adjustment for these differences reveals rapid increases in the cumulative incidence occurring in the first 5 years after delivery for different racial groups. Targeting women with elevated fasting glucose levels during pregnancy may prove to have the greatest effect for the effort required.
D036861:Delivery, Obstetric; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D016640:Diabetes, Gestational / Q000453:epidemiology*; D005006:Ethnicity; D005260:Female; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D039781:PubMed; D013997:Time Factors