['To assess relative expression levels of mRNA for EP3 isoforms EP3-2, EP3-3, and EP3-6 in human myometrium in various physiologic states.', 'Using semiquantitative reverse transcriptase-polymerase chain reaction, we analyzed myometrial samples from 46 women (ten menopausal, ten nongravid premenopausal, 19 gravidas, seven premenopausal misoprostol-treated nongravid women) for the specific expression of mRNA messages for the EP3 receptor isoforms EP3-2, EP3-3, and EP3-6.', 'We found that the expression of EP3-2 was significantly lower in gravid than nongravid myometrium (P < .0001). Levels of the EP3-6 message were higher in gravid samples than in nongravid specimens (P < .02). EP3-3 mRNA was present in higher levels in menopausal samples compared with the other groups.'] Is eP3-2 receptor mRNA expression reduced and EP3-6 receptor mRNA expression is increased in gravid human myometrium?