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Twins are known to be smaller than singleton babies, but up until recent years, routine use of singleton growth charts to plot the growth of twins were still being used. This led to healthy, well-grown twins being misclassified as growth restricted, and often resulted in unnecessary early delivery, exposing these babies to problems of prematurity.

At St George’s, we carried out some large research projects which compared the normal growth of twins to singletons, and have formulated fetal growth charts which are specific to both sharing one placenta (likely to be identical) and those with separate placentas (likely to be non-identical) twins, in order to ensure that the growth of twins were correctly monitored according to their own growth capacity, thereby avoiding unnecessary intervention. This was the first twin-specific growth chart developed in the world, and is now commonly used across many hospitals in the UK.

Predictive Accuracy of Southwest Thames Obstetric Research Collaborative (STORK) Chorionicity-Specific Twin Growth Charts for Stillbirth: A Validation Study

Patterns of Second- And Third-Trimester Growth and Discordance in Twin Pregnancy: Analysis of the Southwest Thames Obstetric Research Collaborative (STORK) Multiple Pregnancy Cohort

Fetal Growth Reference Ranges in Twin Pregnancy: Analysis of the Southwest Thames Obstetric Research Collaborative (STORK) Multiple Pregnancy Cohort