Cigarettes smoked per D^2nd trimester:NRat:Pt:^Mother:Qn
cigarettes smoked per d^2nd trimester:nrat:pt:^mother:qn
Cigarettes smoked per D^2nd trimester:NRat:Pt:^Mother:Qn
cigarettes smoked per d^2nd trimester:nrat:pt:^mother:qn