729 Altered DNA methylation of MMP 9, MMP 14,TIMP 3 and TIMP 4 associated with pregnancyWendy White1, Brian Brost1, Jonathan O’Brien1, ElizabethBaldwin1, William Watson1, Carl Rose1, Norman Davies1, ToddStanhope2, Zhifu Sun3, Stephen Turner4, Vesna Garovic4

1Mayo Clinic College of Medicine, Maternal Fetal Medicine, Rochester,MN, 2Mayo Clinic College of Medicine, Obstetrics and Gynecology,Rochester, MN, 3Mayo Clinic College of Medicine, Biomedical Statisticsand Informatics, Rochester, MN, 4Mayo Clinic College of Medicine,Nephrology and Hypertension, Rochester, MNOBJECTIVE: Matrix metalloproteinases (MMPs) degrade extracellularmatrix; tissue inhibitors for MMPs (TIMPs) regulate this proteaseactivity. Maternal leukocytes at the maternal-fetal interface expressMMPs/TIMPs, controlling trophoblast invasion and angiogenesis.Altered expression of MMP 2, 9, 14, and TIMPs 1-4 have been asso-ciated with establishment of normal pregnancy and adverse preg-nancy outcomes. We sought to characterize differential methylationpatterns in pregnancy.STUDY DESIGN: Methylation profiles of MMP 2, 9 and 14 (6 CpG sitesin 3 genes) as well as 10 CpG sites in 4 TIMP genes 1-4 were charac-terized longitudinally in maternal DNA from blood in 14 women at �16 weeks, at delivery and postpartum and compared with 14 nulli-gravid women. All patients were non-smokers, matched for age andBMI. Genomic DNA was derived from buffy coat, purified, bisulfitemodified and run on the Illumina Methylation Assay platform. Meanmethylation levels at each CpG site were compared using a Students orpaired t-test.RESULTS: Nulligravid and postpartum samples had similar methyl-ation profiles for all genes. MMP 2, TIMP 1 and TIMP 2 were notdifferentially methylated. MMP 9 and 14 were less methylated in earlypregnancy versus postpartum (p�0.0009/p�0.001) and matchednulligravid samples (p�0.02/p�0.009). MMP 9 methylation levelsremained lower at delivery compared with postpartum levels(p�0.000006). TIMP 3 was less methylated in early pregnancy versuspostpartum (p�0.0014) and nulligravid (p � 0.0005). TIMP 4 wasless methylated in the pregnant versus postpartum comparison only(p� 0.0257).CONCLUSION: Nulligravid and postpartum women have similar meth-ylation profiles for the MMP and TIMP genes tested; any changesassociated with normal pregnancy revert back to baseline after deliv-ery. MMP 9, MMP 14, TIMP 3 and TIMP 4 are less methylated inpregnancy compared with non-pregnant controls. Since MMP 9 se-rum levels are known to increase 15x in pregnancy and elevated MMP14 primes for angiogenesis, altered methylation may be a mechanismby which expression is controlled.

730 Profiling maternal plasma cell-free RNA byRNA-sequencing: a comprehensive approachWinston Koh1, Christina Fan1, Yair Blumenfeld2, Ron Wong3,Yasser El-Sayed2, Elizabeth Kogut2, Stephen Quake1

1Stanford University and Howard Hughes Medical Institute, Departmentof Bioengineering, Stanford, CA, 2Stanford University School ofMedicine/Lucile Salter Packard Children’s Hospital, Obstetrics& Gynecology, Division of Maternal-Fetal Medicine, Stanford,CA, 3Stanford University School of Medicine/Lucile SalterPackard Children’s Hospital, Pediatrics, Stanford, CAOBJECTIVE: It is known that fetal specific cell-free RNA is present inmaternal plasma. Cell-free RNA has been studied for non-invasivefetal aneuploidy detection, but the comprehensive cell-free transcrip-tome may also serve as a window for studying placental and/or fetaldevelopment noninvasively. Only a handful of pregnancy specific cell-free RNA transcripts have been characterized, and the comprehensiveprofiling of such RNA has not been performed.STUDY DESIGN: Next-generation sequencing was used to characterizethe cell-free RNA transcripts that are present in maternal plasma atdifferent stages of pregnancy. We analyzed the plasma RNA profiles of5 pregnant women collected prospectively during the first trimester,

second trimester, third trimester, and post partum, as well as those of2 non-pregnant female donors and 2 male donors.RESULTS: Analysis revealed significant enrichment of genes known tobe associated with fetal and placental development in the samplescollected during pregnancy as compared to samples from non-preg-nancy. Among the pregnancies analyzed, 1 had a bilobed placenta andanother experienced preterm labor and delivery. Comparison of thesepregnancies against normal cases revealed significantly different geneexpression pattern across different temporal stages of pregnancy.CONCLUSION: Next-generation RNA sequencing of the pregnancytranscriptome may help identify molecular markers that are predic-tive of pathological pregnancies.

731 Canadian women’s attitudes toward noninvasiveprenatal testing of fetal DNA in maternal plasmaHoward Berger1, Lara Hasan2, Leanne De Souza3, Gerald Lebovic4

1St Michael’s Hospital, Obstetrics and Gynecology, Toronto, ON, Canada,2Case Western Reserve University, Faculty of Medicine, Cleveland, OH,3St. Michael’s Hospital, Obstetrics and Gynecology, Toronto, ON,Canada, 4Li Ka Shing Knowledge Institute of St. Michael’s Hospital,Applied Health Research Centre, Toronto, ON, CanadaOBJECTIVE: Fetal DNA that is found in the maternal plasma has beenproposed as a means for noninvasive prenatal screening and testing offetal chromosomal and genetic abnormalities. Our study aims to de-termine the views, perceptions and attitudes of Canadian women tothis new screening modality.STUDY DESIGN: A specifically designed questionnaire was adminis-tered in the first half of pregnancy to women attending the outpatientantenatal clinic at a tertiary urban hospital. Demographic and socio-economic information was collected. Views and attitudes to currentand new prenatal screening modalities were assessed using a five-point Likert scale. McNamer’s test was used to compare individualresponses regarding the two screening modalities and Cochran-Man-tel-Haenszel analysis was used for univariate analysis of associationsbetween categorical variables.RESULTS: 129 women enrolled in this study. Mean maternal age was31.65 (�/� 4.84) and mean gestational age was 11.65 (�/�3.07). Amajority of women were Canadian born, primiparous and Caucasian(63.6%,55.8% and 53.55%). 45% of respondents had received prena-tal counseling prior to the study. 88% of women state that they wouldperform prenatal screening via fetal DNA in the maternal plasma ifavailable. When compared to conventional screening more womenthink that screening with fetal DNA in maternal plasma could be usedin a negative way to select for desired traits (39.7% Vs. 27.6% P�0.02). On univariate analysis country of birth, ethnicity and agewere associated with increased fear of misuse of this type of screening(P�0.05).CONCLUSION: The use of fetal DNA in the maternal plasma is widelyaccepted in our Canadian population as a future method of non in-

Poster Session V Academic Issues, Antepartum Fetal Assessment, Genetics, Hypertension, Medical-Surgical-Disease www.AJOG.org

S324 American Journal of Obstetrics & Gynecology Supplement to JANUARY 2012