[Is a quantitatively exact prediction of expected birth weight possible using the sonographically determined parameters of biparietal diameter, thoracic diameter and length of the humerus? A prospective study of 285 pregnant patients].

Diagrams of bpd (biparietaldiameter), thorax-d and the length of the humerus have been made by single measurements in 285 pregnant women with exact gestational age and sonoanatomical parameters in the first trimenon. The expected individual birth weight at delivery was to be estimated by the degree of individual deviation from these three normal diagrams. There are statistically clear relations between all the three parameters and the factual birth weights if the delivery is around the normal date of delivery. However, the prediction is only a qualitative, not an exactly quantitative one. The bpd seems to be the best one because of its lowest degree of statistical deviations. An early diagnosis of small-for-gestational-age children, at least with these three parameters, remains uncertain, if not impossible. The average duration of pregnancy in our patients was not 280 days p.m., but less: (280) - 1.23 days p.m. in the group of statistically "purified" patients (i.e. premature newborn under 2,500 gr. and Caesarean-section newborn excluded) and (280) - 2.32 days in the group of statistically "not purified" patients.