Should we screen for gestational diabetes? “The concept of gestational diabetes was popularised before considerations of evidence based medicine came on the scene”

Abstract

Much confusion surrounds the topic of screening for glucose intolerance-hyperglycaemia during pregnancy in terms of who should be screened, how to screen, and the management of those with positive results.2 3 4 Confusion arises from lack of or poor quality evidence, compounded in this instance by a concept (gestational diabetes mellitus) founded on risk of subsequent non-insulin dependent diabetes mellitus rather than outcome of the index pregnancy.5 In addition the criteria for gestational diabetes prescribe a minimum, but not a maximum, level of glucose intolerance, so that any group of women labelled as having gestational diabetes might contain some with glycaemia in the range that qualifies for a diagnosis of non-insulin dependent diabetes, rendering comparisons of different series impossible. Coustan, whose comment is reproduced in my title, suggested four questions which required answers to achieve resolution1: 1. How severe must maternal hyperglycaemia be to measurably worsen pregnancy outcome? 2. Can we intervene to prevent adverse outcomes? 3. Is such intervention cost effective? 4. If so, what is the most appropriate way of screening and detecting the problem? Women with pre-existing diabetes, either insulin dependent or non-insulin dependent, undoubtedly have an increased risk of bearing a child with a congenital abnormality and this risk is …