In this double-blinded prospective study , seventy women undergoing elective caesarean delivery were randomized to receive either intrathecal 7.5 mg Levobupivacaine 0.25 % plus sufentanil 2.5 g ( Group L0 .25 ) , or intrathecal 7.5 mg L 0.50 % plus sufentanil 2.5 g ( GroupControl ) .