METHODS	220 pregnant , non-smoking women with asthma were randomly assigned , by a computer-generated random number list , before 22 weeks ' gestation to treatment adjustment at monthly visits by an algorithm using clinical symptoms ( control group ) or F ( E ) NO concentrations ( active intervention group ) used to uptitrate ( F ( E ) NO > 29 ppb ) or downtitrate ( F ( E ) NO < 16 ppb ) inhaled corticosteroid dose .\