336 SPO Abstracts

209 CLINICAL SIGNIFICANCE OF MEASURING THE UMBILICAL ARTERY SID RATIO AT THE PLACENTAL

AND FETAL CORD INSERTION SITES I Forouzan, P. Samuels, S. Eifex, A.w. Cohen

University of Pennsylvania Medical Center, Philadelphia, PA

Umbilical artery SID ratios vary at different sijes along the umbilical artery. We studied a group of fifty high risk pregnancies in the third trimester. We analyzed the ability of the umbilical artery SID ratio, performed within 7 days of delivery, to predict the likelihood of poor pregnancy outcome among these patients. Poor outcome was defined as small -for- gestational age infants, the presence of meconium at delivery, fetal distress in labor requiring cesarean section, or 5 minute Apgar scores < 7. Twelve patients, (24%) had abnormal SID ratios near the abdominal end of the umbilical cord. Abnormal SID ratios were seen in 9 (18%), and 4 (8%) patients at the mid cord segments and placental insertion sijes, respectively. All those wijh an abnormal SID ratio at placental end of the cord also had an abnormal SID ratio at the mid cord segment and abdominal insertion sije. This, however, was not true for patients who had abnormal measurements at the mid cord or abdominal end of the cord. Poor outcome occurred in 11 patients (22%). An abnormal SID ratio (> mean + 2SD) at the placental insertion sije had a better predictive value (40%) than did abnormal values at the mid cord and abdominal end of the cord (28% and 20% respectively). Conclusion: In our study, the ability to use Doppler blood flow studies to predict poor pregnancy outcome IS less than reported in the obstetric lijerature. Our success in predicting adverse outcomes, however, was improved by measuring the umbilical artery SID ratio at the placental insertion sije.

210 TRICUSPID REGURGITATION: A METHOD OF MONITORING PATIENTS TREATED WITH INDOMETHACIN. R.L. Rosemond, F.H. Boehm, G. Moreau,' H. Karmo'. Dept. of OB/GYN, Vanderbilt Univ. Medical Center, Nashville, TN.

Doppler ultrasound (U/S) has been used to detect fetal ductus arteriosus constriction in up to 50% of patients treated with Indo­methacin. This technique is difficult to perform and results are not entirely reproducible. In this study, we propose an alternate method of monitoring patients on Indocin. Significant ductal constriction will lead to tricuspid valve regurgitation (TR). Using Doppler UIS to detect TR, 30 normal control patients were studied to determine the typical velocity waveform that occurs across the tricuspid valve. The upper limit of normal for regurgitant flow was determined to be .6 m/sec. 45 patients in the same gestational age range who were treated with Indocin (50 mg suppository load, 25 mg PO q 6) for preterm labor were studied using the same tech­nique. Length of therapy was variable, but all patients had at least one study performed per 72 hour interval. Indocin was dis­continued if there was significant regurgitant flow or the amniotic fluid index became < 5 cm. Results: There were 2 cases (4.4%) of TR detected and 4';'es (8.8%) of oligohydramnios (oligo). Both cases of TR resolved within 24 hours and 3 of 4 cases of oligo resolved with 72 hours. The fourth case with oligo delivered with­in 24 hours of stopping Indocin. There were 31 neonatal intensive care unit admissions. There were no instances of persistent fetal circulation or intraventricular hemorrhage. One infant developed mild necrotizing enterocolitis at 30 days of life and one infant developed transient renal tubular dysfunction. The etiology of the renal failure was thought to be related to either gentamycin or Indocin toxicity. Neither of these cases was from the group that developed TR or oligo. We conclude that patients treated with Indomethacin can be safely and easily monitored by observing for the development of TR or oligo and that the incidence of clinically significant ductal constriction may be less than originally reported.

January 1992 Am J Obstet Gynecol

211 COMPARISON OF THE DOPPLER W AVU'ORM CHARACTERISTICS OF THE PROXIMAL VERSUS DISTAL UTERINE ARTERY USING COLOR FLOW MAPPING. R. Allen.' L. Castro, D. Ogunyemi.' K. RoU,x L. Plait, Cedars-Sinai and King-Drew Medical Centers, UCLA School of Medicine, Los Angeles, Ca.

Analyses of Doppler ultrasound flow velocity waveforms (FVWs) have been used to investigate the uteroplacental circulation. Previous studies suggest that uterine artery FVWs vary significantly with the sampling site. Purpose: To determine whether the location along the uterine artery alters the doppler FVWs alld to assess whether observed differences are influenced by gestational age (GA). Metbods: 27 subjects from 18to 40 weeks GA had studies performed. 15 subjects had repested studies at 4 week intervals. The proximal and distal UA were identified with color flow mapping. Pulsed Doppler was then used to obtain the FVWs. The mean SID ratio and RI were calculated from at least 3 wavefonns. The data were analyzed using repeated measures analysis of covariance with and without GA as the covariate and the subject as a random factor for repeated measures. Results: n= number of studies

ANCOV A' For RI and SID Proximal VS. Distal !! mean diff. (SEM) v-value

SID placental 50 0.30 (0.06) .0001 SID non-placental 51 0.50 (0.21) .021 Rl placental 50 0.09 (0.02) .0001 Rl non-placental 51 0.07 (0.02) .0001 * Analysis of covariance without gestational age in the model. Gestational age was not an important covariate in any of the analyses. The changes between proximal and distal Rl and SID ratios were not significantly different between placental and non-placental sides. Conclusions: The SID ratio and Rl decline significantly along the course of the U A and this decline is not influenced by GA. This decline may reflect a decrease in resistance to

flow as the uterine vessels near the placenta. Supported by UCTRDRP Grant#IKT96

212 EFFECT OF SAMPLING SITE ON UMBILICAL DOPPLER INDICES IN INTRAUTERINE GROWTH RETARDATION (IUGR) ~,S.

Sonessonx, G. TessyierX, P. Bonnin,x J.-C. Fouronx. Fetal Cardiology Unit, University of Montreal, Montreal, Quebec.

Previously, we confirmed that the SID ratio, pulsatility index (PI), and resistance index (RI) are higher in the abdominal than placental end of the umbilical artery in normal pregnancy, and that this difference disappears at the end of gestation (International Perinatal Doppler Society, 1991). We hypothesize that this is due to a relative increase in fetal circulatory volume compared to placental volume late in gestation. Therefore, we sought to determine whether this pattern holds true for growth retarded fetuses. Systolic and diastolic velocities were measured at the abdominal (A) and placental (P) ends of the cord of 28 fetuses 28 - 40 weeks gestation with severe IUGR (birthweight < 3rd percentile for GA). The mean A-P difference in all indices remained significant even at the end of gestation. (Table 1) This suggests: 1) that when monitoring these high risk fetuses with doppler studies, sample site should be controlled for in serial examinations, and 2) that the disappearance of the A-P difference in normal fetuses may result from increased fetal blood volume relative to placental volume late in gestation. Table 1 Mean A-P difference in indices (>36 wks)

~S/D ~PI ~RI

Normals 0.29±.6t 0.05±.17t. 0.03±.Olf

IUGA 1.17±.99' 0.33±O.2· 0.10±.08·