Foetal heart rate deceleration with combined spinal-epidural analgesia during labour: A maternal haemodynamic cardiac study

To understand the mechanisms those are involved in the appearance of foetal heart rate decelerations (FHR) after the combined epidural analgesia in labour. Observational study done at University Hospital for 86-term singleton pregnant women with spontaneous labour. Serial bedside measurement of the main cardiac maternal parameters with USCOM technique; stroke volume (SV), heart rate (HR), cardiac output (CO) and total vascular resistances (TVR) inputting systolic and diastolic blood pressure before combined epidural analgesia and after 5, 10, 15 and 20min. FHR was continuously recorded though cardiotocography before and after the procedure. Correlation between the appearance of foetal heart rate decelerations and the modification of maternal haemodynamic parameters. Fourteen out of 86 foetuses showed decelerations after the combined spino epidural procedure. No decelerations occurred in the women with low TVR (<1000dyne/s/cm(-5)) at the basal evaluation. FHR abnormalities were concentrated in 39 women who presented elevated TVR values at the basal evaluation (>1200dyne/s/cm(-5)). Soon after the epidural procedure, the absence of increase in SV and CO was observed in these women. No variations in systolic and diastolic blood pressure values were found. The level of TVR before combined epidural analgesia in labour may indicate the risk of FHR abnormalities after the procedure. Low TVR (<1000dyne/s/cm(-5)) showed a reduced risk of FHR abnormalities. FHR decelerations seem to occur in women without the ability to upregulate SV and CO in response to the initial effects of analgesia.