Intra-partum fetal compromise: prediction and risk stratification prior to labour
File(s)
Author(s)
Prior, Tomas
Type
Thesis
Abstract
Obstetric practice aims to mitigate the potential adverse effects of intra-partum fetal compromise by identifying the compromised fetus and expediting delivery before permanent neurological damage ensues. The ubiquitous use of the cardio-tocograph as a method of intra-partum fetal surveillance has not resulted in a reduction in the incidence of cerebral palsy and has been held responsible for increasing rates of medical intervention in birth. As a result, its use is not recommended in low risk pregnancy. However, the classification of all pregnancies without antenatal complication as low risk may be inappropriate, given that a significant proportion of cases of fetal hypoxia occur within this cohort. A more individualised approach to risk stratification is therefore required. This thesis will report the development of a technique to risk stratify ‘low risk’ pregnancies prior to established labour.
In a prospective observational study, ultrasound assessment incorporating umbilical and middle cerebral artery Doppler, and evaluation of 1st trimester B-HCG and PAPP-A levels, were investigated to determine if these parameters were predictive of subsequent intra-partum fetal compromise and the need for emergency delivery. Ultrasound assessment was undertaken both at term prior to established labour (in 604 cases), and at 35 – 37 weeks gestation (in 125 cases). A single trained practitioner undertook all ultrasound assessments, and staff managing the labour were blinded to the ultrasound results. Cases were followed up within 72 hours of delivery and intra-partum and neonatal outcomes evaluated. Multiple parameters (umbilical artery PI, middle cerebral artery PI, the cerebro-umbilical ratio and umbilical venous flow) were combined to create a composite risk score to predict intra-partum fetal compromise. Finally, maternal hyper-oxygenation was investigated as a potential therapeutic tool to improve fetal haemodynamics.
Ultrasound assessment prior to active labour can identify fetuses at high and low risk of subsequent intra-partum compromise, even within a ‘low risk’ population. The cerebro-umbilical ratio may be the single most predictive parameter, with fetuses with the lowest ratios at significant increased risk of subsequent compromise in labour (RR 21.00, 95% CI 2.92 – 151.00). Maternal hyper-oxygenation did not influence the measured fetal Doppler parameters.
Ultrasound assessment may facilitate a more individualised approach to fetal assessment, allowing women to make better informed decisions regarding labour and delivery.
In a prospective observational study, ultrasound assessment incorporating umbilical and middle cerebral artery Doppler, and evaluation of 1st trimester B-HCG and PAPP-A levels, were investigated to determine if these parameters were predictive of subsequent intra-partum fetal compromise and the need for emergency delivery. Ultrasound assessment was undertaken both at term prior to established labour (in 604 cases), and at 35 – 37 weeks gestation (in 125 cases). A single trained practitioner undertook all ultrasound assessments, and staff managing the labour were blinded to the ultrasound results. Cases were followed up within 72 hours of delivery and intra-partum and neonatal outcomes evaluated. Multiple parameters (umbilical artery PI, middle cerebral artery PI, the cerebro-umbilical ratio and umbilical venous flow) were combined to create a composite risk score to predict intra-partum fetal compromise. Finally, maternal hyper-oxygenation was investigated as a potential therapeutic tool to improve fetal haemodynamics.
Ultrasound assessment prior to active labour can identify fetuses at high and low risk of subsequent intra-partum compromise, even within a ‘low risk’ population. The cerebro-umbilical ratio may be the single most predictive parameter, with fetuses with the lowest ratios at significant increased risk of subsequent compromise in labour (RR 21.00, 95% CI 2.92 – 151.00). Maternal hyper-oxygenation did not influence the measured fetal Doppler parameters.
Ultrasound assessment may facilitate a more individualised approach to fetal assessment, allowing women to make better informed decisions regarding labour and delivery.
Version
Open Access
Date Issued
2014-12
Date Awarded
2016-02
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Kumar, Sailesh
Bennett, Phillip
Sponsor
The Moonbeam Trust
Grant Number
P35907
Publisher Department
Department of Surgery & Cancer
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)