Abstract
Public health indicators generally operate in the world as credible, apolitical and authoritative. But indicators are less stable than they appear. Clinical critiques of Intrauterine Growth Restriction (IUGR) criteria have been forthcoming for decades. This article, though, takes up the measuring and calculation gradients of IUGR in the ultrasound machine itself, including the software algorithms that identify IUGR. One hospital where research was conducted incorrectly predicted pathological birth outcomes 14 of 14 times. We are at a historical moment when the global use of prenatal diagnostic ultrasound for the express purpose of assessing IUGR is set to escalate. Medical imaging device corporations like Siemens, Toshiba, General Electric and Phillips are quite literally banking on it, and new forms of ultrasound technology and diagnostic software are increasingly available on smartphones, tablets and laptops. Clinical guidelines for IUGR – assumed to be authoritative and evidence-based – are evolving right along with the installation throughout the world of the technology capable of diagnosing it. Maternal malnutrition remains the single strongest predictive factor for IUGR, regardless of the technological investments currently amassing to identify the indicator, which is cause for a reassessment of priority spending and investment.
Acknowledgements
Biostatistician Lawrence McCandless graciously helped me understand the components of Hadlock's famous equation. Any remaining mistakes are my own. Thanks also to Songi Park, Richard Rottenburg and the Biomedicine and Indicators groups at the Max Planck Institute in Halle, Germany; Liz Roberts, Tim Johnson and the Grand Rounds audience at University of Michigan's Medical School; and Carole Browner, Baindu Kosia and Alex Collins. A late night taxi ride with Michael Montoya and Claris Thompson prompted the first draft. This article was finalised during a fellowship at the Käte Hamburger Kolleg/Centre for Global Cooperation Research, University of Duisburg-Essen, Germany.
Disclosure statement
No potential conflict of interest was reported by the author.
Notes
1. IUGR (Intrauterine Growth Restriction, previously Intrauterine Growth Retardation) is not the same as SGA (small for gestational age), though in the generalist and lay educational literature about pregnancy, it is common to see the terms used synonymously. IUGR is a foetal estimate and SGA is measured at birth. The 2013 ACOG Practice Bulletin No.134 uses the term Fetal Growth Restriction, though a new acronym was not introduced. The terminology shift is subtle, but such changes have clinical implications. In this case, the shift effectively moves clinical attention from the mother's body – which may simply not be getting enough food to eat – to the foetus, who can be taken up as an individual patient.
2. All names are pseudonyms.
3. One of the biggest ironies of the ‘gold standard of ultrasound dating’ and its alleged superiority is that ultrasound estimates of foetal growth use patient-recalled LMP as an algorithmic factor.