Gestational diabetes lacks clear diagnostic threshold
medwireNews: Research into gestational diabetes needs to move on from quantifying the effect of maternal glucose intolerance on perinatal outcomes, say the authors of a meta-analysis.
Diane Farrar (Bradford Royal Infirmary, UK) and colleagues identified 25 studies that assessed the relationship between glucose levels and perinatal outcomes, in 207,172 women. Given the amount of data available, they conclude that more studies of similar nature are not necessary, except perhaps in low-income countries, particularly sub-Saharan Africa.
However, the results of their meta-analysis confirm that there is a linear relationship between glucose levels (based on oral glucose tolerance or challenge test) and a wide range of perinatal outcomes, including shoulder dystocia, preeclampsia, macrosomia and large for gestational age. The associations were stronger for fasting than post-load glucose tolerance.
“The lack of a clear threshold at which risk increases means that decisions regarding thresholds for diagnosing gestational diabetes are somewhat arbitrary”, the researchers write in The BMJ.
They note that the International Association of Diabetes and Pregnancy Study Groups adopted a threshold glucose level at which the risk of birthweight, cord C peptide and percent body fat above the 90th percentile were increased 1.75-fold.
But Farrar et al stress that these outcomes are all obesity-related, and that adopting a single threshold for diagnosing gestational diabetes assumes that all outcomes are of equal importance. “[W]ould clinicians and parents consider induction of labour to be as important as shoulder dystocia or an infant requiring neonatal intensive care?” they ask.
The team believes that future research should focus on the effects of treatment on perinatal outcomes that are linked to gestational diabetes.
“Economic evaluations and research are required to determine what relative importance women, their partners, and care givers attribute to the different outcomes to determine the level at which clinical and cost effectiveness is maximised”, they say.
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