Abdominal palpation to determine fetal position at the onset of labour: an accuracy study

Abstract

Since the late 19th Century, abdominal palpation of the gravid uterus has been routine, worldwide obstetric practice to determine fetal position. A systematic review showed a dearth of research on the accuracy of this ubiquitous test. A test accuracy study was carried out prospectively to assess accuracy of abdominal palpation (index test) to identify the Left-Occipito-Anterior (LOA) fetal position at the onset of labour, in nulliparous women over 37 weeks’ gestation, with ultrasound as the reference standard. Trained observers blind to the index test results performed the ultrasound independently. Midwives palpation data on the position of 629 women were obtained and 61 (9%) fetuses were verified as LOA by ultrasound. The sensitivity, specificity and likelihood ratio of abdominal palpation to detect LOA position were 34% (23-46), 71% (67-74) and 1.2 (0.83-1.74) respectively. Higher accuracy was achieved by midwives with experience > 5 years (OR 4.02; 1.2-12.9) and those who worked in the community (OR 0.15; 0.03-0.9). Accuracy of abdominal palpation to determine LOA fetal position at the onset of labour is poor. If future research demonstrates that the optimal fetal position of LOA exists, midwives will need to confirm fetal position at the onset of labour by ultrasound to prognosticate.