356 SPO Abstracts

404 PATIENT ATTITUDES TOWARDS PRENATAL TESTING: CHORIONIC VILLUS SAMPLING VERSUS AMNIOCENTESIS . .

Caccia N ,Johnson JH, Barna T ,Hutton E University of Toronto, Toronto, Ontario

Patient acceptance of, and attitudes towards prenatal diagnostic procedures play an important role in determining the extent of their use. Our study compared the attitudes of 253 women undergoing either chorionic vi llus sampl ing (CVS) (72 transcervical (TC), 24 transabdominal (TA) and 6 both) or second trimester amniocentesis (n=151) to assess the factors influencing their choice of procedure and their perceptions of the procedures. Self-adninistered questionnaires were completed immediately before and after the procedure (9-12 wks for CVS patients and 15-17 wks for amniocentesis patients) and follow-up was obtained by telephone interview after their test resul ts were known. The results showed that the earl ier timing of the test and the nature of the termination procedure were important reasons for patients choosing CVS, whi le physician advice and a lack of knowledge about CVS played important roles in patients choosing amniocentesis. The procedures were found to be significantly less painful than expected (P<O.05). Of the 3, TA-CVS was significantly more painful than amniocentesis whi le TC-CVS was the least painful. The patients were satisfied with most aspects of the procedures; the least satisfaction was with the time spent waiting for results. lie conclude that patient education and physician advice are important factors influencing a woman's choice of prenatal diagnostic procedure. Overall, satisfaction with prenatal testing was high in both groups, and was associated with less physical discomfort than anticipated.

405 COMPARISON OF INTRAPARTUM FETAL MONITOR TRACINGS OF KARYOTYPICALLY ABNORMAL AND CONTROL INFANTS MC Treadwellx, Y Sorokin, RK Bhatia, RD Eden, MI Evans. Center for Fetal Diagnosis and Therapy, Hutzel Hospital, Wayne State University, Detroit, Michigan.

An increased incidence of fetal distress among infants with chromosomal abnormalities has long been appreciated. To determine if there are any specific monitoring patterns associated with chromosomal abnormalities the intrapartum tracings of 17 postnatally diagnosed karyotypically abnormal infants were obtained. Controls were randomly selected from infants born on the same day at the same gestational age (+/- 1 week). The tracings from these two groups were independently evaluated by two board certified perinatologists unaware of the chromosomal status of the infants. Comparison of the monitor interpretations showed: 1) The karyotypically abnormal group was more likely to have decreased or absent short (p<O.OOI) and long term (p<O.OI) variability. 2) Accelerations were more likely to be present in the control group (p<O.OOI). 3) No significant differences were found in the baseline heart rates or in the presence or frequency of mild, moderate, or severe variable or late decelerations. The contraction frequency was the same in the two groups, despite the increased use of pitocin in the control group. These findings may reflect underlying central nervous system abnormalities as opposed to utero­placental insufficiency but are not specific to karyotypically abnormal infants.

January 1991 Am , Obstet Gvnecol

406 UMBILICAL CORD BLOOD pH DISCORDANCY AND ITS RELATION TO FETAL ACIDEMIA. James F X Egan. Anthony M. Vintzileos, Winston A. Campbell, John F. Rodis, David A. McLean, Alfred O. Fleming, William E. Scorza. University of Connecticut Health Center, Farmington, CT

The aims of this retrospective study were to: 1) establish the normal range of pH dffference between venous (V) and artenal (A) umbilical cord blood (ApH) throughout gestation and 2) investigate the relationship between discordancy in pH and fetal acidemia (cord arterial pH < 7.20). The study population included 520 patients delivered in 1987-88 with gestational ages between 24-42 weeks who had both V and A cord gases recorded. The mean gestational age (±SO) was 33.3 weeks (±4.4). ~: The mean V pH was 7.33 and mean A pH 7.28. The mean (±SO) of .1pH was 0.062 (±0.048). Since the data were not unrtormly distributed, the median .1pH (0.055) and the 90%ile (.1pH 0.12) were determined. Linear regression analysis between gestational age and .1 pH showed that .1 pH is not gestational age dependent (R2 =0.003). Of the 520 neonates 53 were discordant (D) (.1pH>0.12) and 467 were nondiscordant (NO) (.1pHsO.12). The frequency of acidemia was greater in the 0 group than the NO group (22/53 or 42% vs. 38/467 or 8%, p<0.0005). The data were then analyzed as four groups: group I, nonacldotic-NO (n=429); group 2, nonacidotic-O (n=31); group 3, acidotic-D (n=22)) and group 4, acidotic-NO (n=38). As compared to group 1 there was a progressive decline in cord ApH, AHC03', and base excess in groups 2 through 4. In concert with this progression on the arterial side, in groups 2 and 3 there was an increase in the VpH, Vp02 and decrease in the VpC02; in group 4 there was a decrease In VpH, Vp02, base excess and an increase in VpC02. The maintenance of normal VpH and gases in groups 2 and 3 suggests a compensatory mechanism which allows for more efficient gas exchange in cases of fetal compromise. Based upon analysis of the clinical characteristics, it is suggested that cord compression in the presence of normal placental reserve is the most likely insult causing .1pH discordancy.

407 THE EFFECT OF RUPTURE OF FETAL MEMBRANES (ROM) ON FETAL ACOUSTIC STIMULATION (FAS) IN LABOR Kathleen A. Kuhlman M 0 and Carmen J. Sultana, M.O.X Jefferson Medical College of Thomas Jefferson University Hospital, Philadelphia, PA

Diminished FHR responses to FAS have been reported 10 normal fetuses intrapartum. Amniotic fluid may facilitate sound transmission; ROM may result in decreased fetal response to FAS. We hypotheSIze that FHR response to FAS is independent of membrane status, presumably because of the vibratory component of FAS. The purpose of the present study is to compare the FHR response to FAS before and after ROM. IRB-approved written consent was obtained. Inclusion criteria: labonng patients at 36-41 wks gestation. singleton vertex; normal ammollc fluid volume; and reactive FHR tracing Exclusion cnteri .. : posillve urme drug screen; abnormal newborn exam; Apgar (5) <7; and umbilical artery pH <7.15. After a 20 minute period of FHR monitoring, FAS with an arllficial larynx (Western Electric 5C) was applied near the fetal head for I second: I) before amniotomy (Pre· ROM); and 2) after (Post·ROM). FHR tracings for the 10 minute epochs before FAS (Pre-FAS) and after (Post-FAS) were analyzed for: FHR baseline; #15 bpm accels; max accel amplitude (MAA), max accel duration (MAD); and % accel time. Twenty-one patients were enrolled; 1 was excluded for positive drug screen. All 20 fetuses showed FAS responses; 18 had ~15 bpm accels, and 2 had ~10 bpm accels Pre-FAS versus Post·FAS values are as follows: a) Pre-ROM: MAA increased from 25.8:t30.2 bpm to 34.0:t28.3; MAD increased from 85.5:t50 4 to 257 0:t112.5; and % accel time increased from 33.9±23.3 to

59.3±25.5; b) post-ROM; MAA increased from 18.3±10.8 to 30.5:t31.2; MAD increased from 52.3±48.7 to 213.5±157.3; and % accel time mcreased from 19.5±15 I to 49.5±27.0. Paired t-tests showed no statistical differences for Post-FAS changes, in Pre-ROM versus Post-ROM groups. There were no Post-FAS differences 10 FHR baseline or #15 bpm accels. We conclude that the status of membranes does not significantly alter Post-FAS FHR responses in labor.