OP08.04: Is it possible to create ultrasonographic Bishop score? Repeatability and reproducibility of potential parameters – preliminary study

Abstract

Objectives: The primary objective was to compare point-of-care ultrasound (POCUS) and routine third trimester ultrasound versus routine antenatal care in reducing the incidence of undiagnosed breech presentation in labour. Methods: We included data from St. George's (SGH) and Norfolk and Norwich University Hospitals (NNUH). Pregnancies were grouped according to whether they received routine third trimester scan (SGH) or POCUS (NNUH). Women with multiple pregnancy, preterm birth < 37 weeks, congenital abnormality and those undergoing planned Caesarean section for breech presentation were excluded. Undiagnosed breech presentation was defined as: a) women presenting in labour or with ruptured membranes at term subsequently discovered to have a breech presentation; b) women attending for induction of labour at term found to have a breech presentation before induction. The primary outcome was undiagnosed breech presentation in labour. Secondary outcomes included mode of birth and neonatal adverse outcomes. Results: Before and after the implementation of routine third trimester scan or POCUS, there were 16,777 and 7,351 births in SGH and 3,974 and 4,522 in NNUH, respectively. The rate of breech presentation in labour was consistent across all groups (3-4%). The rates of undiagnosed breech in labour were 1.0 (95% CI: 0.2-1.7) and 4.9 (95% CI: 3.8-6.0) per 1,000 births with and without routine third trimester scan. There were ∼4 fewer undiagnosed breech cases per 1,000 births with routine scanning (p < 0.0001). A similar effect was observed with routine POCUS: undiagnosed breech fell from 7.6 (95% CI: 4.9-10.3) to 0.7 (95% CI: 0.0-1.4) per 1,000 births. Neonatal outcomes were generally poorer in undiagnosed breech: higher rates of Apgar score < 7 at 5 th minute (9.5 versus 0.7%, P < 0.0001), need for resuscitation (34.8% versus 1.35%, P < 0.0001) and neonatal unit admission (9.0 versus 1.2%, P < 0.0001). Conclusions: Routine third trimester scan or POCUS reduces the rate of undiagnosed breech in labour.OP08.

Repeatability and Reproducibility of Potential Ultrasonographic Bishop Score Parameters

“…We estimated the minimal sample size based on the table presented by Bujang et al [ 26 ]. Based on the available literature and the preliminary study, we concluded that the value of the intraclass correlation coefficient (ICC) for the null hypothesis should not be less than 0.5 [ 20 , 24 , 27 ]. With such a null hypothesis, two observations per patient and a power of 90%, the minimum sample size should not be less than 87 subjects.…”