OP34.01: Tomographic imaging of the pelvic floor in nulliparous women: limits of normality

Results: See Table 1. Different ultrasound machine – transducer combinations made a modest difference to 10 mm axial CRL dating (max 1 days; 9.8–10.5 mm), 10 mm lateral CRL dating (max 0 days; 9.9–10.5 mm) and finally 40 mm lateral CRL dating (max 2 days; 39.0–42.4 mm). Conclusions: All measurements used to estimate CRL fetal gestation were within clinically acceptable limits of fetal accuracy (as recommended by Loughna et al) in both axial and lateral planes at 10 mm, and lateral plane at 40 mm irrespective of different machine/probe combinations . Further studies are needed to establish the impact of such errors in the diagnosis of miscarriage when the range of measurements is lower.