Pregnancy alone lowered the plasma AA concentrations of ileu, leu, and val when compared to their concentrations in nonpregnant nonsmokers. Plasma concentrations of val, ileu, and leu were significantly higher in pregnant smokers than in pregnant nonsmokers. Therefore, the utilization of BCAA was more reduced in pregnant smokers than that which could be predicted from plasma AA concentrations of nonpregnant nonsmokers.
Amino Acids, Branched-Chain Embryonic and Fetal Development