[Relation between motilin concentration and progesterone level in normal pregnancy and early postpartum]

Plasma motilin and serum progesterone concentrations were measured in 180 women with gestational age between 5-40 weeks and 3-5 days after delivery. In addition, motilin and progesterone concentrations were also measured in blood collected from 20 healthy nonpregnant women at midcycle. There was no significant difference of plasma motilin levels between nonpregnant women (366.12 +/- 96.23 ng/L) and women in the 1st trimester of pregnancy (384.40 +/- 110.30 ng/L). The motilin concentration was significantly lower in the 2nd trimester (323.96 +/- 125.10 ng/L) compared with that in the 1st trimester, P < 0.05. then it reached to the lowest level in the 3rd trimester (121.04 +/- 27.88 ng/L) with P < 0.01. At 3-5 days after delivery, motilin concentration (443.05 +/- 147.70 ng/L) was significantly higher than that in the 3rd trimester. The mean level of serum progesterone was 11.00 +/- 2.70 nmol/L in midcycle, whereas 84.42 +/- 40.00, 175.73 +/- 85.69 and 1438.35 +/- 331.88 nmol/L in the 1st, 2nd and 3rd trimester of pregnancy respectively. However, progesterone level decreased rapidly after delivery and reached to a significantly lower level (13.54 +/- 9.88 nmol/L). The results demonstrated that progesterone levels were increased along with gestational age whereas motilin levels were decreased. A negative correlation was found between them (r = -0.42, P < -0.01). It suggested that progesterone appeared to have a profound inhibitory effect on motilin. The decreased motilin level might partially be responsible for gastrointestinal hypomotility during pregnancy.