Measurement of amniochorionic membrane thickness using high-frequency ultrasound.

Premature rupture of the membranes (PROM) accounts for approximately 30 per cent of all preterm deliveries. PROM is thought to be mainly due to a decrease in membrane integrity. The aim of our investigation was to determine, post-partum after 28 normal deliveries, the thickness of the amniochorionic membrane using a 20 MHz high-frequency ultrasound. The data obtained were compared with histological sections for measurement accuracy using a linear regression analysis method. The membrane thickness of the total study group was 0.83 +/- 0.11 mm (0.72-1.08 mm). Based on a statistical comparison with the histological sections, the high-frequency ultrasound examination was shown to be highly reliable, with a correlation coefficient of r = 0.96 (P < 0.0001). High-frequency ultrasonographic examinations of membrane thickness are an objective and reliable method and may be a gain to prenatal diagnostics once this method can be used in vivo.