Abstract： Objective To detect aquaporin 3,8 and 9 (AQP-3,-8 and-9) mRNA expression in human oligohydramnios placenta. Methods Each of five placenta samples were collected from women who presented either oligohydramnios or normal amniotic fluid volume and underwent elective cesarean sections at term in our hospital between July 2005 and December 2005. The expressions of AQP-3,-8 and-9 mRNA were detected by reverse transcriptase-polymerase chain reaction ( RT-PCR ) and compared between two groups. Results RT-PCR showed that the expression of AQP-8 mRNA was significantly lower in oligohydramnios placenta than that in normal pregnancy placenta at term ( 0.582 6±0.061 8 vs 0.791 1 ±0.168 9,P<0.05);the expressions of AQP-3 and-9 mRNA in oligohydramnios placenta was not significantly different from normal pregnancy (P>0.05). Conclusion AQP-8 may play a major role in maternal-fetal fluid exchange in oligohydramniotic women.