[Usefulness of selected ultrasonographic methods for evaluation of fetal weight in twins]

Evaluation of three mathematical methods, based on ultrasound examination, in order to estimate foetal weight in twins and compare them with actual birth weight. Retrospective analysis of ultrasonicly assessed 27 pairs of twin babies, who were born within 10 day of ultrasound examination and then outcome's comparison with newborn weight, measured just after the delivery. The ultrasonic measurements were performed to calculate estimated foetal weight using mathematical models of Shepard, McCallum and Hadlock. All outcomes were compared to birth weight. Statistical analysis, employed in our research, was percentage error according to formula: % = (EFW - BW) x 100/EFW (EFW - estimated foetal weight, BW - birth weight). The mean foetal weight calculated according to Shepard's method was 2605.9 g and 2651.6 g, relatively for the first (I) and second (II) twin baby. By using McCallum's method outcomes were as follows: (I) -2558.4 g (II) -2655.4 g and for Hadlock's method: (I) -2480.9 g and (II) -2540.3 g. Actual birth weight came to 2664.1 g for (I) and 2639.6 g for (II). Percentage error was found -2.23, using Shepard's method, -4.13, using McCallum's method and -7.38, using Hadlock's method, for the first twin-baby. Relatively, for the second twin-baby, values were found as follows: 0.45, 0.59, -3.91. Shepard's method is the most helpful in prediction of birth weight in twin pregnancy. Separate evaluation of each of twin babies can be more significant indicator in prognosis of appearance in intrauterine growth retardation (IUGR), comparatively to evaluation of weight's discordance between both twin-foetuses.