CHANGES IN EXPRESSION OF THE CYCLOOXYGENASE GENE IN HUMAN FETAL MEMBRANES AND PLACENTA WITH LABOR

OBJECTIVE: Our objective was to examine the expression of the gene coding for cyclooxygenase, the central enzyme in prostaglandin synthesis, in human placenta and fetal membranes during pregnancy and before and after labor at term. STUDY DESIGN: Expression of the gene for cyclooxygenase was examined with Northern hybridization to ribonucleic acid from human placenta throughout pregnancy and human amnion and chorion decidua in the late third trimester. RESULTS: Expression was undetectable in trophoblast during the first and second trimesters. Expression in amnion and trophoblast increased 3.5- and 2.5-fold, respectively, in association with labor. CONCLUSIONS: Our results suggest that the increase in prostaglandin synthesis within the uterus that is seen with the onset of labor is associated with an increase in the expression of the gene cyclooxygenase.