Volume 166 Number I, Part 2

372 PLASMA ATRIAL NATRIURETIC FACTOR AND ARGININE VASOPRESSIN RESPONSES TO INDOMETHACIN IN THE OVINE FETUS. Martin P,R. Walker MD. Cecilia Y. Cheung PhD" Robert A. Brace PhDx. Division of Perinatal Medicine, Dept of Reproductive Med., Univ. of California, San Diego, CA.

Prostaglandins have been implicated in the release of atrial natriuretic factor (ANF) and arginine vasopressin (A VP). We hypothesized that indomethacin (10) would cause a fall in plasma ANF and A VP in the fetus. After a 1 hr control, we gave 0.31 mg/kg of ID i.v. followed by a 0.D15 mg/kg/min infusion to 9 near term chronically catheterized ovine fetuses. Hemodynamic data were continuously monitored for 5 hours and plasma ANF and A VP levels determined hourly. During 10 infusion, plasma ANF increased from control of 214 ± 58 pg/ml to 701 ± 193 pg/ml at 1 hr then remained at 427 ± 89 pg/ml (ANOVA, P<O.OOOOI after log transformation). Plasma AVP levels rose from 3.1 ± 0.8 pg/ml to 7.4 ± 2.5 pg/ml by 3 hr, to 20.5 ± 11.5 pg/ml at 4 hr, returning to 7.4 ± 2.5 pg/ml at 5 hr (ANOVA, P=0.0005). Multivariate analyses revealed that the increases in plasma ANF (R = 0.56, P=O.017) and AVP (R = 0.76, P=O.OO(4) were associated with changes in fetal arterial pressure but not in blood volume or venous pressure. In summary, our data do not support the hypotheses that 10, at these doses, causes a reduction in plasma ANF or AVP in the ovine fetus. We speculate that 1) The elevation in arterial pressure in response to 10 leads to an increase in ANF and 2) The rise in A VP may mediate the increase in arterial pressure. In addition, the observed rise in A VP may explain the clinical observation that indomethacin use in the human fetus leads to oliguria and oligohydramnios.

373 PREVALENCE OF COCAINE ABUSE IN A TER­TIARY CARE CENTER: M J PaidasX+, M.G. Neerhof,

M. HussonX, RJ. Librizzi. Mount Sinai Medical Center, New York, NY and Pennsylvania Hospital, Philadelphia, PA.

To address the need for routine screening in a urban hospital with 4600 deliveries per year (65% private, 35% service), a cocaine prevalence study was undertaken at Pennsylvania Hospital. The ,.creening was anonymous, and accomplished over 2 months. 441 urine specimens were obtained from pregnant women presenting or being admitted to Labor and Delivery. The urine was tested for benzoylecgonine, a cocaine metabolite, using the enzyme immunoassay, EMITR d.a.u.™ Cocaine Metabolite Assay (SYV A Co, Palo Alto, CA) RESJlLTS Population ~ (+) Screen Percentage % Private 295 2 0.68 Service 132 4 3.03 Unregistered ....l1 ...3. lldL Total 441 9 2.04 Service refers to patients followed in the prenatal clinic at our institution. This group (132) was divided into high risk (23), low risk (103), and teen (6). The number of positive screens were 0,4,0 respectively. Private (295) refers to patients followed by private practitioners (248) and those followed by a maternal fetal medicine practice (47). The number of positive screens in these latter two categories were 2 and 0 respectively. CONCLIJSION The overall prevalence of positive cocaine screening is low at our institution. Routine screening may be beneficial in selected populations including unregistered patients.

SPO Abstracts 379

374 THE RELATIONSHIP BETWEEN FETAL PLATELET FUNCTION IN THE THIRD TRIMESTER AND UMBILICAL DOPPLER VELOCIMETRY. ~x+, MJ Haut" A Ludomirsky and RJ Bolognese. Mount Sinai School of Medicine, New York, NY and Pennsylvania Hospital, Philadelphia, PA.

Reduced fetal platelet counts have been associated with abnormal umbilical doppler waveforms. To investigate the relationship between fetal platelet function and umbilical artery doppler velocirnetry, we retrospectively compared the results of platelet aggregation. a measurement of platelet function, with the systolic/diastolic (s/d) ratio of the umbilical artery flow velocity waveform. Our previous research in platelet function in the developing fetus suggests that 'normal' responses in platelet aggregation appear in the third trimester. The study population consisted of 10 pregnant women ranging from 28-36 weeks gestational age. Umbilical sid ratios were obtained in all patients prior to cordocentesis. Platelet aggregation studies using ADP 2 x 104 M, were performed turbidometrically using a Sienco Dual Sample Platelet Aggregation Meter (Sienco, Inc., Morrison CO.). 200 microliters of platelet rich plasma were obtained from each fetal blood specimen after centrifugation. RESULTS: Gestational % Aggregation Gestational % Aggregation

toADP toADP 28 30.5 33 29.0 29 5.0 34 65.0 30 7.5 34 42.0 31 1.5 34 100

Doppler derived sid ratio did not conelate with the platelet response to the aggregation agonist ADP 2x104 M. (p >0.05, r=0.07). CONCLUSION: In this small series, there is an apparent lack of correlation between a measurement of platelet function, namely aggregation response, and umbilical doppler velocirnetry. Further studies in platelet activation and methodology are now in progress to verify our initial results of fetal platelet function.

375 SERUM CYTOTOXICITY LEVELS IN PATIENTS WITH SPONTANEOUS AND RECURRENT ABORTION.

JJ walker M MacLean+, R Wilson+, JA Thomson+, Univers~y Departments of Obstetrics and Medicine, Glasgow Royal Infirmary, Scotland, UK.

We have previously shown that there are immunological abnormal~ies in patients with spontaneous (SA) and recurrent abortion (RA). As the resuHs suggested that these may be triggered by some serum factor we have studied serum cytotoxic~y levels in 20 healthy pregnant women, 9 with SA and 20 with RA, by measuring the release of 51 Cr from K 562 cells. Serum cytotoxicity levels did not differ significantly between healthy pregnant women and those with SA (25.7± 7.7% VS 23.7±2.9%). Levels were significantly higher in women with RA (33.4±3.2% P<0.001) compared to controls and SA. Elevated serum cytotoxicity was also seen in 5 RA prior to and following confirmation of their pregnancy (35±1.9% vs 33.9±3.2% ). Concluslons.These findings would suggest that the increased cytotoxic~y seen in RA is not triggered by the pregnancy. Also ~ would appear that the mechanism responsible for triggering the immunological changes seen in SA and RA differ.