| Summary: | <p>Human growth begins at conception and continues into adult life. Growth is usually classified as normal or abnormal using the expected attained size at a given age. The statistical analysis of growth data has been of interest to many academics from a wide range of disciplines over the last century. The study of fetal and neonatal growth is complex, and the many remaining clinical questions require complex statistical methodology. In this thesis, I have focused on growth in the prenatal period, namely fetal and newborn growth.</p> <p>The thesis highlights the potential pitfalls in methodology, statistical methods, and reporting of studies aimed at creating fetal charts. I propose a checklist for evaluating the methodological quality of studies that provides a rough guide of the minimum information that should be reported in these studies. This checklist is not intended to commend or discard studies, but rather to act as a consensus guideline to improve consistency and as a guide for evaluating similar studies for future research in human growth studies. The thesis assesses approaches for developing charts of attained size at a given age and the velocity gain (rate or speed of growth) of a fetus. It aims to address some of the statistical issues that relate to fetal and neonatal growth studies.</p> <p>The thesis also focuses on fetal velocity. This work is novel as there are currently no fetal velocity standards in existence. The methodologies discussed have previously been applied to child growth data, but not to fetal data, to the best of my knowledge. In this thesis, I construct the first fetal growth velocity standards. Such standards were not yet available largely due to lack of appropriate, good quality longitudinal fetal data.</p> <p>All of the work and research carried out as part of the thesis was embedded within the International Fetal and Newborn Growth Consortium for the 21<sup>st</sup> Century (INTERGROWTH-21<sup>st</sup> Project). The primary aims of the INTERGROWTH- 21st project were to produce international growth standards for practical clinical applications and to monitor trends in populations using three sets of data describing fetal growth (n=4,321 women), postnatal growth of preterm infants (n=201 preterm infants), and newborn size (weight, length, and head circumference) for gestational age (n=20,486 newborns). The design and conduct of these studies are detailed elsewhere and have already resulted in numerous publications, including four papers published in <em>The Lancet</em>. I was the responsible statistician for these publications and undertook all of the statistical analyses.</p>
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