The APOLLO Study
Analysis of fetal Position at the Onset of Labour and Labour Outcomes: The APOLLO Study
The aim of the study was to investigate the association between fetal position at the onset of labour and birth outcomes.
The APOLLO study was unusual as being a project that was initiated, designed and led by midwives. The research question was developed mainly by myself and one of the other team members, and arose from our consideration of the work of Jean Sutton who proposed that the optimal fetal position at the onset of labour was left occipito-anterior (LOA). This theory was gaining ground among the midwifery body and in the midwife literature yet it was not evidence-based. It was being taken up such that methods of modifying fetal position to LOA were being investigated and tested. The purpose of our study was to investigate whether the LOA position at labour onset was associated with superior outcomes. If this were to be the case it was also important to have evidence on whether midwives could accurately determine fetal position at the onset of labour or induction of labour. Inclusion criteria for the study were nulliparous women, over 37 gestational weeks, with a cephalic presenting fetus and with no known fetal abnormalities. Women were not included in the study when labour was established and this was determined as when the cervix was fully effaced and 4cm dilated, with regular uterine contractions. We recruited 1250 eligible women to the study and fetal position was assessed by usual midwife palpation and recorded. It was also assessed by abdominal ultrasound that was considered to represent the `gold standard' and midwives and women were blinded to the ultrasound scan results.
For my MPhil degree I compared the data from the midwife palpation and abdominal ultrasound in a test accuracy study to determine the accuracy of abdominal palpation in identification of fetal position. It showed the use of abdominal palpation, by midwives, as a means to correctly identify the LOA fetal position is poor. It also showed no significant association between maternal BMI, gestational age, rupture of membranes, placental location or the use of any one particular abdominal palpation manoeuvre and the correct assessment of the LOA fetal position. Although it is acknowledged that the study was not powered for the detection of the non-LOA fetal positions, sensitivity of palpation to detect other fetal positions was low in all groups. Likelihood ratios were also low across all fetal positions and this low rate of accuracy raises questions about the validity of clinical decisions based on the findings of abdominal palpation, by midwives, to detect fetal position at the onset of labour.
The findings from the other part of the APOLLO study showed that there was no association between the LOA fetal position and mode of delivery or any other birth outcomes.
Publications from the APOLLO Study
The association between fetal position at the onset of labor and mode of delivery: a prospective cohort study Aishah Ahmad, Sara S. Webb, Bernadette Early, Alice Sitch, Khalid Khan and Christine MacArthur. Accepted manuscript online: 8 AUG 2013 09:33AM EST | DOI: 10.1002/uog.13189
Abdominal palpation to determine fetal position at labor onset: a test accuracy study. Sara S Webb, Maria N Plana, Javier Zamora, Aishah Ahmad, Bernadette Earley, Christine MacCarthur, Khalid S Khan. Acta Obstetricia et Gynecologica Scandinavica. Vol 90, Issue 11. November 2011, pp 1259–1266.