Obese parturients have lower epidural local anaesthetic requirements for analgesia in labour

Background. There are no studies comparing local anaestheticrequirements for obese and normal parturients. Obesity has beenassociated with a higher incidence of Caesarean section andhigher levels of epidural block have also been found in obeseobstetric patients, suggesting they may require less local anaesthetic.The aim of our study was to estimate the minimum local analgesicconcentration (MLAC) of bupivacaine for obese and non-obeseparturients. Methods. Otherwise healthy parturients (n=32) requesting epiduralanalgesia were enrolled in this up–down sequential allocationstudy. Women were in active labour (3–6 cm cervical dilatation)with visual analogue pain scores (VAPS) >40/100 mm. Subjectswith BMI >30 kg m^–2 were allocated to the obese groupand BMI