Open AccessCorrelation models for monitoring fetal growth
Author(s) -
Yuan Feng,
Luo Xiao,
Li Cai,
Stephanie T. Chen,
Eric O. Ohuma
Publication year - 2020
Publication title -
statistical methods in medical research
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.952
H-Index - 85
eISSN - 1477-0334
pISSN - 0962-2802
DOI - 10.1177/0962280220905623
Subject(s) - biparietal diameter , correlation , ultrasound , gestational age , fetal growth , fetus , medicine , mathematics , head circumference , statistics , radiology , pregnancy , biology , genetics , geometry
Ultrasound growth measurements are monitored to evaluate if a fetus is growing normally compared with a defined standard chart at a specified gestational age. Using data from the Fetal Growth Longitudinal Study of the INTERGROWTH-21 st project, we have modelled the longitudinal dependence of fetal head circumference, biparietal diameter, occipito-frontal diameter, abdominal circumference, and femur length using a two-stage approach. The first stage involved finding a suitable transformation of the raw fetal measurements (as the marginal distributions of ultrasound measurements were non-normal) to standardized deviations (Z-scores). In the second stage, a correlation model for a Gaussian process is fitted, yielding a correlation for any pair of observations made between 14 and 40 weeks. The correlation structure of the fetal Z-score can be used to assess whether the growth, for example, between successive measurements is satisfactory. The paper is accompanied by a Shiny application, see https://lxiao5.shinyapps.io/shinycalculator/.