Assessment of foetal age on the basis of the selected dimensions of the thorax.

BACKGROUND The correct definition of foetal age is a substantial problem in forensic medicine, gynaecology, obstetrics and anthropology. OBJECTIVES The goal of the study was the mathematical assessment of the foetal age with the use of thorax selected dimensions. MATERIAL AND METHODS The material consisted of 110 foetuses aged 4-7 months of foetal life, including 50 females in the CRL range: 80-233 mm. The following methods were incorporated: preparation, anthropological, image digital acquisition, Image J computer system measurements and statistical analysis. For each foetus the following sizes were taken: crump-rump length - CRL (v-tub), total body length - v-pl as well as brachial circumference - BC, thoracic circumference - TC and clavicular length - CLA. RESULTS Six monofunctional mathematical models were elaborated: Bertalanffy growth curve, three Gompertz function based models and two exponential models to assess examined parameters increase along with t age. Model no. 3 for Gompertz function revealed the biggest consistency with v-pl measurements for every determination ratio R2 = 0.9944 for exponential model R2 = 0.9917. Multiple regression analysis was used to elaborate mathematical formula to assess the foetal age (determination factor R2 = 0.9997) with BC, TC parameters. CONCLUSIONS Examined parameters BC and TC were found useful in foetal age assessment in the evaluated age range. Elaborated mathematical model can be applied in clinical practice e.g. in foetal age ultrasound determination.