P28.02: Establishment of ultrasound references value for fetal anogenital distance and perineal muscular complex measurements: could it be a future prospect in our antenatal anorectal malformation ultrasound diagnosis?

Anorectal malformation are usually under diagnosed. The main goal of this study was to establish prenatal ultrasound references value for perineal muscular complex, anogenital distance for future perspective of antenatal diagnosis improvement. The perineal muscular complex was visualised and measured in the longitudinal axis. When it couldn't be seen easily, a three-dimensional ultrasonography with tomography ultrasonography imaging was used and perineal muscular complex appeared on tangential axis. Tomography ultrasonography imaging or triplane application were used to show rectum, anal canal and skin perineum part and measure was performed in the skin perineum part. Then anogenital distance was measured. Anorectal angle was measured as the angle formed between the rectum and the anal canal, and the results were expressed in degrees. All data processing was performed using SPSS 20. A total of 259 fetuses were examined by ultrasound. Maternal age ranged from 19 to 44 years (mean, 30.6 y; SD±5.6). Gestational age at measurement ranged from 19 to 41 weeks (mean, 31 weeks; SD±6). Normal fetal perineal muscular complex diameter ranged from 5 to 23 mm (mean 12.82 mm; SD, ±5.6mm). The measurement of anogenital distance ranged from 4.7 to 40 mm (mean, 16.8; SD±7.4). Anorectal angle mean was 111.89° ranging from 100.83° and 118.96°. There was a significant positive relationship between perineal muscular complex diameter, anogenital distance, anorectal angle and gestational age (p<0.005). Establishment and application of normogram for measurements could be the first step to improve our antenatal diagnosis and post-natal surgical management.