Weight gain during pregnancy does not influence the spread of spinal analgesia in the term parturient

Background: It is still controversial whether the spread of spinal anaesthesia in pregnancy is influenced by particular physique. Investigation was based on a clinical observation that parturients with a pronounced ''pregnant'' physique, e.g., generalised oedema and heavy abdomen, tended to develop more cephalad sensory blockades than parturients without these physical signs. Using weight gain during pregnancy as a measure for the physique at term, we aimed to determine whether this parameter influences the distribution of analgesia after subarachnoidal injection of plain bupivacaine. Methods: Thirty women presenting for elective Caesarean section were studied. All the women received 13.5 mg plain bupivacaine via subarachnoid injection at the L2-3 interspace. Thirty minutes after the injection, while the women were in the supine position with a left lateral tilt on a horizontal operating table, the maximum cephalad extent of sensory analgesia (loss of sensation to sharpness of pinprick) was determined. Results: Neither weight gain during pregnancy (6-22 kg, range), height (152-185 cm), weight (56-98 kg) nor body-mass index (20.2-31.8 kg/m(2)) correlated with the cephalad spread of sensory blockade. Conclusion: In parturients, weight gain during pregnancy, height, weight and body-mass index did not influence the extent of sensory analgesia after subarachnoidal administration of plain bupivacaine.