Fetal membrane water permeability is decreased in polyhydramnios: a new explanation for an old...

503 MECHANISMS FOR REGULATION OF INTRAMEMBRANOUS AMNIOTICFLUID (AF) ABSORPTION: GENE EXPRESSION OF PROLACTIN (PRL)RECEPTOR NEPHRIN FATANEH AMIDI1, DAVE GAYLE1, SAM WANG1,MICHAEL ROSS1, 1Harbor-UCLA Medical Center, Department of Obstetricsand Gynecology, Torrance, CA

OBJECTIVE: Although absorption of AF across the chorioamnion (in-tramembranous flow) is central to AF volume regulation, little is knownregarding its regulation. Nephrin-like proteins regulate transcellular proteinpermeability in several organs at epithelial podocytes. PRL, having water-mineral hormone properties, also has a potential role in AF volume. As amnioncells have similar structures as podocytes, we postulated that Neph1 and PRLmay regulate fetal chorioamnion permeability and thus influence AF volume.We sought to determine the expression of Neph1 and PRL receptor genes in ratfetal membranes and placenta. Results are compared to beta-actinmRNA levels.

STUDY DESIGN: Pregnant Sprague Dawley rats (n = 3) at gestation day 18were anesthetized and the uterus exposed. Individual placentas and fetalchorioamnion were harvested and homogenized to isolate total RNA for mRNAdeterminations using real time RT-PCR.

RESULTS: Fetal membranes expressed high levels of neph1 mRNA whichwas significantly greater than placental levels ((1.3 ± 0.3 vs 0.01 ± 0.01 AU,p = 0.03). Fetal membranes also had elevated levels of PRL receptor mRNA thatwere higher than placenta levels (0.21 ± 0.05 vs 0.05 ± 0.03 AU, p = 0.08).

CONCLUSION: These finding indicate the expression of Neph1 and PRLin fetal membranes. We postulate that Neph1 and PRL regulate fetal membranepermeability to protein and electrolytes, respectively. Alterations in expressionof these genes may lead to AF volume abnormalities.

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505 EARLY MID-TRIMESTER AMNIOTIC FLUID LEPTIN CONCENTRATION:INDICATOR OF FETAL GROWTH? BON-SANG KOO1, SUN-KWON KIM1,WON-DUK JOO1, JONG-YUN HWANG1, JAE-YOON SHIM1, HYE-SUNGWON1, DAE-SHIK SUH1, PIL RYANG LEE1, AHM KIM1, 1Asan MedicalCenter, University of Ulsan, Obstetrics & Gynecology, Seoul, South Korea

OBJECTIVE: Monitoring fetal growth and assessing its predictors play animportant role in prenatal care. The aim of this study is to examine whether theearlymid-trimester amniotic fluid leptin concentration is related to birth weight.

STUDY DESIGN: Amniotic fluids were collected from women who receivedgenetic amniocentesis in early mid-trimester. We excluded complicatedpregnancies (preeclampsia, preterm birth, twin pregnancy, and endocrinedisorder, etc.). Wemeasured leptin concentrations in the amniotic fluid of smallfor gestational age (SGA) (n = 18), appropriate for gestational age (AGA)(n = 22), and large for gestational age (LGA) (n = 16). The three groups werematched for maternal age, maternal bodymass index (BMI) and gestational ageat the time of amniocentesis. The amniotic fluid leptin concentrations weremeasured by enzyme-linked immunosorbent assay (ELISA).

RESULTS: The mean gestational ages at the time of amniocentesis were18.6 ± 1.9 (mean ± S.D) weeks. There was no significant difference in leptinconcentrations of SGA, AGA, and LGA groups (6.97 ± 2.06 ng/ml, 7.82 ± 2.13ng/ml, and 7.28 ± 1.50 ng/ml, respectively).

CONCLUSION: The early mid-trimester amniotic fluid leptin concentra-tion is not useful as a marker of fetal growth.

506 TECHNIQUES FOR EFFECTIVE COMMUNICATION FOR PARENTSWITH UNEXPECTED FETAL ABNORMALITIES MICHAEL MARCOTTE1,BRIAN BROST2, BRIDETTE SYFRETT3, 1Good Samaritan Health Center,Obstetrics and Gynecology, Cincinnati, OH 2Mayo Clinic, Obstetrics andGynecology, Rochester, MN 3Medical College of Ohio, Obstetrics andGynecology, Toledo, OH

OBJECTIVE: To develop teaching points for an obstetric and pediatricresident curriculum on techniques for effectively communicating bad news toparents during the perinatal period.

STUDY DESIGN: A 16 question multiple choice survey was administered toall obstetric and pediatric residents (n = 32), former patients from our MFMpractice who had experienced a perinatal loss or fetal abnormality (n = 46) anda national panel of experts working with parents who have lost a child (n = 64).

RESULTS: 100% of the residents and 50% of the experts and patientsresponded to the survey. All three groups felt patients should be given control ofwhen, how, and in the presence of whom the unexpected news should be givento them. Sensitivity to the patient’s vulnerability and the parent’s feelings ofbeing out of control were clearly important to all groups surveyed. All groups feltthat a face-to-face follow-up should occur one week after the initial visit whenunexpected news was communicated. Asking the patient questions like ‘‘what doyou understand about the problem?’’ was agreed on by the residents and expertsto be an effective way to understand how well the patient comprehended theissues surrounding the abnormality.

CONCLUSION: Giving unexpected new to patients in the perinatal periodabout their fetus is difficult for the patient, doctor and all those involved. Takingadequate time, listening, speaking clearly with correct medical terms andhonesty about what is known and unknown regarding the fetal diagnosis andprognosis is essential for effective communication of bad news to parents. Inaddition, providing follow-up after the inital counseling session will increase thepatient and family’s sense of control.

Volume 189, Number 6Am J Obstet Gynecol

SMFM Abstracts S197

FETAL MEMBRANE WATER PERMEABILITY IS DECREASED IN POLYHY-DRAMNIOS: A NEW EXPLANATION FOR AN OLD PROBLEM STEPHANIEMANN1, NATALIA DVORAK1, ROBERT TAYLOR1, 1University of California,San Francisco, Obstetrics or Gynecology, San Francisco, CA

OBJECTIVE: Polyhydramnios is a condition associated with significantperinatal morbidity. However, the exact pathophysiology of this condition isunknown. Prior studies from our laboratory have shown that the water channelsAQP1 and – 3 are present in human fetal membranes from term pregnancieswith normal AF volume. Therefore, we hypothesize that in pregnancies withpolyhydramnios, there is altered expression of these AQPs.

STUDY DESIGN: Placentas were collected fromwomenwho presented withpolyhydramnios (AFI > 24.0cm); normal placentas were collected from womenwith intact membranes and normal AF volume who were not in labor andunderwent an elective cesarean sections at term (37-40 wks). The amniondirectly overlying the placenta and from the free floating reflected membraneswas sampled (total of four samples from each placenta). RNA and protein wereisolated from the amnion. RT-PCR and TaqMan quantitation were used toanalyze expression of AQP1and -3mRNA. Western blots and immunohisto-chemistry were used for the protein analysis.

RESULTS: As shown in the chart, AQP1 mRNA is significantly increased inthe reflected amnion; there is no significant change in AQP3 mRNA expressionin amnion from polyhydramnios. Western analysis showed no AQP1 or 3 inpolyhydramnios. These results were confirmed by immunofluourescentlocalization.

CONCLUSION: Though amnion expression of AQP1 is significantlyincreased in polyhydramnios, no protein was detectable. The excess AF inpolyhydramnios results in an increase in AQP1 mRNA levels but a reduction intranslation of these water channels. These results suggests that the excess AFaccumulation in polyhydramnios is due to a reduction in water transport out ofthe amniotic cavity. We speculate that therapies focused on increasing AQP1protein expression may be useful for treating polyhydramnios.