The use of the cerebroplacental ratio in the latent phase of labour to predict adverse outcomes in a resource-limited setting

Background. Risk stratification of pregnant women may decrease the perinatal mortality rate in South Africa. This relies on the assessment of the referring health facility and timeous presentation of the patient. Inaccurate dating affects the ability to detect growth restriction. Patients requiring referral may go undetected and deliver with the inappropriate level of care. Doppler studies can assist in detecting at-risk fetuses.  Objectives. To describe the short-term outcomes of fetuses with a normal or abnormal cerebroplacental ratio (CPR) according to the various definitions in the literature.  Methods. A cohort of 200 pregnant women were prospectively recruited while in early labour. Patient history including previous ultrasound scans were obtained. Ultrasound was done for biometry, umbilical artery (UA), middle cerebral artery (MCA) and uterine Dopplers, and the CPR was calculated. Labour and delivery details were recorded. An association between an abnormal CPR, adverse outcomes and composite score was determined.  Results. Less than a tenth (7.7%; n =15) of the participants had a CPR <1.08. Furthermore, 16.5% ( n =31) of the participants were <5th centile and 24.2% ( n =47) were <10th centile. The composite score of adverse outcomes in those with and without a CPR <5 th centile was not significant ( p =0.737). There was no association between adverse outcomes ( p =0.179) or a composite score ( p =0.237) and the CPR cut-off of the 10th centile. Moreover, there was no association between an abnormal CPR and adverse outcomes after adjusting for confounders. There were no cases of perinatal death or neonatal encephalopathy.  Conclusion. An abnormal CPR was not clinically useful in detecting fetuses at risk of adverse outcomes in early labour regardless of the CPR cut-off. However, this is reassuring when normal and may if combined with other parameters still prove useful.