<正> Plasma motilin concentrations were measured in 135 women during the second andthird trimesters of pregnancy and 3～5 d after delivery and the results were compared withthose of 20 healthy nonpregnant women.The mean plasma motilin concentration （323.96±125.10 ng/L） in women during the second trimester of pregnancy was lower than in healthynonpregnant women （366.12±96.23 ng/L） （P<0.05）

but that was significantly higher thanin women during the third trimester of pregnancy （121.04±27.00 ng/L） （P<0.01）;theplasma motilin concentration in women during 3～5d after delivery （443.05±140.79 ng/L）was significantly higher than that in pregnant women （P<0.01）.The results showed thatpregnancy appears to have a profound inhibitory effect on plasma motilin

and this may partlybe responsible for the gastrointestinal hypomotility associated with pregnancy.