Individualized growth charts for ultrasound measurements can significantly improve fetal monitoring.

OBJECTIVE: For monitoring pregnancies it is useful to reduce unnecessary examinations due to wrongfully assumed growth retardation in cases with a small fetal growth potential. It also makes sense to improve the detection of objectively retardated children in order to a disproportionately high growth potential. It was the aim of this study to modify the standard growth charts for ultrasound parameters according to parental influences to better display the individual growth potential.
MATERIAL AND METHODS: In a prospective trial 1,390 ultrasound measurements of 174 completed pregnancies were observed. For all patients a standard questionnaire was conducted in which possible predictors for fetal growth were collected. Customizing the growth charts had been achieved by (1) calculating the general impact of parental factors on the ultrasound measurement values, (2) plotting the individual growth charts for each pregnancy and (3) analyzing the difference of every observed measurement from either unchanged normal values or customized growth charts.
RESULTS: The obtained biparietal diameter measurements all in all are 291 mm closer to the individualized charts than to the unmodified charts. The total improvement of all thoracal diameter measurements was found to be 294 mm, the summarized advancement of all abdomen circumference values was 1,005 mm and the femur length measurements are 296 mm nearer to customized charts. All results were statistically significant. DISCUSSION: This is the first time the impact of several predictors on ultrasound growth charts had been analyzed. While other working groups have demonstrated the benefit of customizing the fetal weight and length, this concept had never been carried forward onto the growth charts for ultrasound values. The method to adjust the common mean values by so called 'modifiers' is derived from the mathematical concept of the sequential first-trimester screening for Down's syndrome. For customizing growth charts this approach seems to be useful as well. The feasability and the statistical benefit of customizing ultrasound growth charts has been demonstrated in this work. A larger study seems to be promising and should be performed. Further improvements could be obtained by using normal growth charts which were derived from the examined cohort.