208 Ventricular functional responses to alteredloading conditions in the fetal heart: a sheepstudy with acute fetal ductus arteriosus occlusionJason Hashima1, David Sahn2, Muhammad Ashraf2,Vanessa Rogers3, Stephen Langley3, LowellDavis1, Roger Hohimer1, Juha Rasanen4

1Oregon Health and Science University, Obstetrics and Gynecology, Portland,OR, 2Oregon Health and Science University, Pediatric Cardiology, Portland,OR, 3Oregon Health and Science University, Pediatric Surgery, Portland, OR,4Oregon Health & Science University, Maternal Fetal Medicine, Portland, OROBJECTIVE: We hypothesized that during acute fetal ductus arteriosus(DA) occlusion (DO) left ventricular performance is improved byacutely increased preload, while an increase in right ventricular after-load has a negative impact on its function.STUDY DESIGN: Nine ewes with singleton pregnancies underwent sur-gery at 120-126 gestational days (term 145 days) for the placement ofa vascular occluder around fetal DA. Fetal carotid artery and jugularvein were cannulated. After a 5-day recovery, fetal heart rate (FHR),right (RVSV) and left (LVSV) ventricular stroke volumes were mea-sured by ultrasonography. Using pulsed-wave tissue Doppler imag-ing, left and right ventricular lateral wall longitudinal myocardial ve-locities were obtained at the level of mitral (MV) and tricuspid (TV)valve annuli. Ventricular systolic function was assessed by measuringisovolumic contraction velocity (IVCV) and its acceleration (load-independent index of ventricular contractility) and diastolic functionby measuring isovolumic relaxation velocity (IVRV) and its deceler-ation. From TV regurgitation jet, dP/dT was calculated to estimateright ventricular contractility. All the measurements were obtained atbaseline, 15 and 60 minutes after DO, and 15 minutes after release ofDO.RESULTS: All the data are presented as means (SD).* p�0.05, com-pared with baseline.CONCLUSION: Acute DO in fetal sheep increases LV preload and RVafterload. During DO, LVSV increased and RVSV decreased, respec-tively. The rise in LV preload did not affect LV contractility, howeversigns of diastolic dysfunction were observed. Right ventricle was ableto maintain its systolic and diastolic function during an acute increasein afterload. These findings suggest that fetal LV could be more sen-sitive to acutely altered loading conditions than RV.

209 Effect of antenatal betamethasone on blood glucoselevels in nondiabetic and diabetic gravidasJennifer Jolley1, Priya Rajan2, Rita Petersen1, Deborah A. Wing3

1University of California, Irvine, Obstetrics and Gynecology, Orange, CA,2Northwestern University, Obstetrics and Gynecology, Chicago, IL, 3UCIrvine Medical Center, Obstetrics and Gynecology, Orange, CAOBJECTIVE: To characterize the maternal glycemic response to beta-methasone in nondiabetic compared to diabetic subjects, and to eval-

uate if maternal characteristics including glucose tolerance test resultprior to receipt of betamethasone predict development of significanthyperglycemia in nondiabetic gravidas.STUDY DESIGN: Blood glucose levels in 22 nondiabetic and 11 diabeticpregnant subjects were recorded for 48 hours following administra-tion of betamethasone. Maximum blood glucose value and time tomaximum value was compared between groups. Area under the curve(AUC) calculations were used to express the duration and degree ofsignificant hyperglycemia for individual subjects. These summarymeasures were then correlated to subject demographic and laboratorycharacteristics to determine a profile of the nondiabetic pregnant pa-tient at risk for significant hyperglycemia following administration ofbetamethasone.RESULTS: The mean maximum blood sugar value was higher for dia-betics (205 mg/dL vs. 173 mg/dL, p� � 0.01), however the mean timeto the maximum was not statistically different (20.4 hours vs. 26.8hours, p� 0.16). The value of a 50 gram oral glucose tolerance testgiven prior to administration of betamethasone was highly correlatedwith the amount of time spent with significant hyperglycemia fornondiabetic subjects (rho� 0.59, p� �0.01). Morbidly obese subjectsspent less time with significant hyperglycemia than those with lowerbody mass indices (p� 0.03).CONCLUSION: Nondiabetic pregnant subjects demonstrate significanthyperglycemia after receipt of antenatal steroids at a time when pre-mature delivery may occur. Consideration should be given to closemonitoring of the glycemic response in nondiabetics with elevatedglucose tolerance testing prior to the receipt of betamethasone.

210 Transplacental passage of acetaminophenJoshua Nitsche1, Hannah Penn2, Wendy White1,Jonathan O’Brien1, Carl Rose1, Norman Davies1,Loralie Langman2, William Watson1, Brian Brost1

1Mayo Clinic College of Medicine, Maternal Fetal Medicine,Rochester, MN, 2Mayo Clinic College of Medicine, LaboratoryMedicine and Pathology, Rochester, MNOBJECTIVE: Nearly all the information concerning the transplacentalpassage and fetal effects of acetaminophen comes from study of acutesupratherapeutic overdose. Surprisingly little is known about howquickly and how much acetaminophen crosses the placenta after atherapeutic dose. This study aims to describe the pharmacokinetics ofacetaminophen in normal unlabored term pregnant women.STUDY DESIGN: After obtaining IRB approval, 34 women at term with-out medical or obstetrical complications were enrolled in the study.Each was administered 1000 mg of acetaminophen orally at varyingtime interval prior to a scheduled cesarean section. Maternal venousblood and fetal cord blood were obtained at the time of delivery, andthe acetaminophen levels were determined using gas chromatogra-phy-mass spectroscopy.RESULTS: Values were stratified into the following groups according tothe time (in minutes) of acetaminophen administration prior to de-livery: 30-60 (n�10), 61-90 (n�12), 91-120 (n�4), 121-180 (n�4),181� (n�4). The mean and standard errors of the mean are providedin the table and graphically represented in the figure.CONCLUSION: Acetaminophen appears in both maternal and fetalblood at similar levels as soon as 30 minutes after administration. Inboth mother and fetus the levels remain relatively constant until 3hours after administration, at which time they begin to decline. Acet-aminophen rapidly crosses the placenta and its clearance from thefetus parallels the time course seen the maternal circulation.

www.AJOG.org Clinical Obstetrics, Medical-Surgical-Disease, Neonatology, Physiology-Endocrinology Poster Session I

Supplement to JANUARY 2012 American Journal of Obstetrics & Gynecology S105