Strengths and Limitations
A key strength of this review is that it is the first to provide a
comprehensive summary of evidence on the association between birth size
or premature birth and future GDM risk. This study followed the
methodological recommendations presented in the Cochrane Handbook, MOOSE
guidelines, and GRADE criteria 27-29.
Moreover, this study included previously unpublished data and a large
sample size.
Nevertheless, this study has some limitations. First, the included
studies were old and may not represent the current clinical practice.
The definition of GDM proposed by the IADPSG in 2010 has resulted in an
increase in GDM prevalence 2, 3, 53. For
example, the prevalence of GDM in the United States increased from 4.6%
in 2006 to 8.2% in 2016 53. The median
prevalence of GDM in the control groups of the included studies was
2.9%. However, empirical evidence suggests that relative effect
measures are, on average, consistent across different settings; in the
present study, we estimated absolute risk differences separately for
low-, moderate-, and high-prevalence settings54. Second, 5 of 15 studies divided birth
size and preterm birth categories into three or more comparative groups,
which could not be combined into two comparison groups of interest.
This lack of data required
methodological adjustments, as described previously. Lastly, this review
only assessed certainty in estimates of association between prognostic
factors and an outcome. Future studies are required to determine whether
these factors can help risk-stratify pregnant women and improve the
clinical management of GDM.