286 SPO Abstracts

PREVENTION OP PREECLAMPSIA: LOW-DOSE ASPIR.IN IN NUllIPAR.OUS WOMEN: A DOUBLE-BLIND, PLACEBO­CONTR.Oll.ED TR.IAL ILSihJL S. Canti •• E.. Phillip •• xM. Klob_ff,x D. MeN.lli.,' L. R.oeeo,' ....t du NICHD MFM N.twook. B.du.da. Ma.ylond OBJECTIVE: TIu primary' obj «tin of dsi. trial .... 1D ...... du .ff.et of low.cio,. "'PiriA an. Ute inciaence of pte.clamp,i •. Secondary O1ltc:olttes weft! bin!. .... ipt ond du im:id_ •• of , .... ti...w hyp • .-.i .... p .. te .... bin!. ond c.~~..,...u, .. tuclati .... STUDY DESIGN: 3135 lsealdtywom ... from 7 m.dieal emte .. were nndomly ani""d at 13-27 week. , ... , .. i.., to ntei,.. 60 m,/d of ...,irin 61-1570) ou ",aldUng placobo 6sa 1565). 0... t...:Ind liftywo ...... (4.8%) wer. lo.t ta fall_-"I' • ....t 2985 wer. follow.d to do. eid af pr.~. Gtftati...w hyp.rteIIfi..,W&f d.nn.d .. blood p ........ af at I.ut 140 mm Hi 'Yf1Dlie ....t/';. 90 mm He diutalie ... 2 aeeAfi .... at I_t' J.cnan 'Part. Pr •• c1amp.ia ...... d.lin.d .. , .... ti...w J.ype.-.i ... phu prateimria (2: 300 !"i 124 "'a. 2: 2. bydip.tick an2 aee ... i"", adu.t ''''''''' 'Put). RESULTS: n.. im:id...,. af p ••• c1amp.ia .... low.r.lnot not .iplie ... t1y .a (".0 .051) in d>. Alpirin'rG1IfI (4.7%,.,. 63%.nlati .. ri. of 0.74. 95% ecmkdenc. interval. 0.548-1.003). Th .... wer. "" diffir_u b.twul1 the 2 'rG1IfI' .. ,udin& im:id ..... of , .... ti...w hyp.", .... i ... (6.73%,.,.5.93%) 0.

im:id ..... of all form. of hyp.",eruiOll (11.4% ,.,. 12.2%). Howeve •• dte im:idenc. of ob""Ptio plae." ... w ... i,.uliell1t1y!Up" (p.O.OI2) in th. Alpi.in ,.""!' (0 .7% n. 0.1% •• elative risk 5 .6.95% e...lid_. int.rvaI 1.24-25). n.. ....... "" differ..., .. in od>.. outcom. nriobl •• (Tobl.). CONCLUSIONS: Low-do •• Alpirin th.ropy .... aflOeiat.d with a 26% dtcrn". in die incidence of preeclampsia; hOW"''', P.,inatal O1ltcome was .. ," a.ffected. Bee ..... of ... im: ..... d risk of ob""tio pl ... ...-. routiM "'. of low-do .. AIp_i.in th.rapy in k ... ldty ..wlip ... .".. ",om ... i. _ ....... ted . (5.opported by NICHD)

GA at .... domi ... tian (wI<) GA at d.li,..'Y (wI<)

<37...k (%) Bin!. w.ipt (g)

< lOth %iI. (%) C ........... etian (%) Ptriftatal death (%)

A.pirin 61.1485) Plac.bo 61= 1500) 19.8±4.4 38.6±3.2

10.6 3230±556

4.6 16.9 1.4

19.8±U 38.8±2.9

9.8 3227±565

5.8 17.2 0.92

2 PROLONGED BLOCKADE OF NITRIC OXIDE SYNTHESIS IN GRAVID RATS PRODUCES SUSTAINED HYPERTENSION, PROTEINURIA, THROMBOCYTOPENIA AND INTRAUTERINE GROWTH RETARDATION. ~ Hertelendy,* M. Molnar,* T. Siitii.* Dept. Ob/Gyn, st. Louis University, St. Louis, MO, and Inst. Pathophysiol., Semmelweis Med. Univ., Budapest, Hungary. OBJECTIVE: To test the hypothesis that chronic inhibition of nitric oxide (NO) synthesis in pregnant rats can produce sustained, systemic hypertension with its sequelae. STUDY DESIGN: Pregnant rats were instrumented on dl4 of gestation (delivery d22) and infused continuously via the femoral vein with L-nitroarginine (L-NAME) (0.5mg/IOOglb) at a flow rate of 0.3m1/h (Exp), or with saline (Con), from dl8 until 2 days postpartum. Blood pressure was recorded via an aortic catheter for 30 min before infusion (basal). and at the same time each day thereafter, in freely moving conscious animals. Urinary protein, platelet count, blood chemistry and wt of newborn pups were measured. Data were analyzed by ANOV A or t-test. RESULTS: MAP increased from 97 to a max of 134 mmHg and remained elevated until delivery, after which it fell to nonpregnant levels (115 mmHg) despite continuing infusion of L-NAME. 24h urinary protein excretion increased 3-fold, platelet count decreased by 50%, and the mean wt of pups at birth was 3.2g (Exp) vs 5.6g (Con), while there was no difference in time of delivery or litter size. No significant differences were found in blood chemistry. CONCLUSION: Chronic inhibition of synthesis of the potent vasorelaxant NO in gravid rats leads to sustained hypertension, providing a simple new model for preeclampsia and IUGR.

January 1993 Am J Obstet Gynecol

3 THE RELATIONSHIP BETWEEN FETAL BIOPHYSICAL PROFILE SCORE AND FETAL PH. FA Manning, R. Snijders, C.R. Harman, K. Nicolaides. Ob/Gyn. HSC, Winnipeg. King'. College. London. OBJECTIVE: To determine the immediate relationship If any between the fetal BPS and the presence and degree of umbilical vein acidosis. STUDY DESIGN: The fetal BPS was done immediately before cordocentesis, interpreted according to a standardized method and recorded. Subsequently ultrasound-guided umbilical vein cordocentesis was done and an aliquot analyzed immediately under standardized condition to determine blood gas values and pH. Umbilical vein pH was recorded both as absolute values and as noonaJ or abnoonaJ (> 2S0 below mean) according to standard gestational age adjusted curves. 493 paired observations of BPS and umbilical vein pH were obtained of which 104 were single samples from growth retarded fetuses (>2S0 below mean for gestational age) and 389 were sequential samples In allo-immune fetuses. RESULTS: The BPS results were normal (>8/10) in 403 observations (81.7%), equivocal (6/10) in 33 (6.9%), and abnormal «4/10) in 57 (11.4%). In contrast the umbilical vein pH was normal in 429 observations (87%) and abnormal In 64 (13%). A highly significant linear correlation was observed between BPS and umbilical vein pH (r2-0.717, p<O.OOI) and mea" pH per BPS grouping (r2=0.93 p<O.OO3). Mean pH ranged from 7.37 ± 0.07 (2S0) for a BPS of 10 to 7.05 ± 0.14 with a BPS of O. These linear correlations persisted when the observations were stratified by gestational age and by high risk category. Predictive accuracy was uniform at the extremes of BPS score distribution: All 403 instances of a noonaJ BPS yielded a normal pH (range 7.21>-7.41) and all 7 instances of a BPS of 0 yielded an abnormal pH (range 6.93-7.13). Intermediate BPS results yielded intermediate predictive accuracy: the Incidence 01 acidosis with a BPS of 6 was 39.5%, with a BPS 01 4 (25 cases) was 56% and with a BPS of 2 (22 cases) was 76%. The pattern of variable for Intermediate scores covered the possible spectrum and was not related to predictive accuracy of acidosis. CONCLUSIONS: These data appear to confirm that the fetal BPS bears a direct relationship to the presence and severity of fetal acidosis.

4 INTRAVENTRICULAR HEMORRHAGE IN VERY LOW BIRTHWEIGHT INFANTS: CLINICAL FACTORS AND PLACENTAL PATHOLOGY. CM Salafja,X C Kamens,x L Ernst,X EJ Woif, AM Vintzileos, T

Rosenkrantz.x Depts. Pathology, Pediatrics, Ob/Gyn, University of Connecticut Health Center, Farmington, CT. OBJECTIVE: To examine relationships among obstetric factors, placental pathology and intraventricular hemorrhage (IVH). Are de­livery indications, delivery mode, or placental lesions associated with increased risk of IVH? STUDY DESIGN: Of 339 liveborn singleton infants we ighing <1500 grams born at Univ. of CT Health Center for whom maternal, neonatal and placental data were available, primary complications leading to delivery were premature membrane rupture in 151 /339 (45%), prema­ture labor in 88/339 (26%), suspected abrupt ion in 27/339 (8%), and preeclampsia in 73/339 (21 %). Excluded were deliveries for isolated growth retardat ion, fetal anomalies, and placenta previa. Placental lesions included acute and chronic inflammatory lesions (grades 0-4) , decidual vascular pathology and histologic abruption (grades 0-4). IVH was diagnosed by cerebral ultrasonogram <72 hours of birth. RESUL. TS: IVH occurred in 30/339 (11 .5%). Stepwise logistic re­greSSion analysis showed significant, independent effects of only 2 factors on risk of IVH: gestational age and presence of either or both severe acute inflammation and extensive abrupt ion (odds ratio 1.8 per lesion). Complications leading to delivery and delivery mode were not associated with IVH incidence. IVH occurred in 8/30 (26.7%) inlants with both severe histologic chorioamnionitis (grade 3-4) and extensive evidence of abruption (grade 3-4), in 221168 (13%) infants with either severe inflammation or extensive abruption, and in 9/134 (6.7%) infants with !l§.iltw lesion. CONCLUSIONS: Severe histologic chorioamnionitis and extensive histologic abruption are independently related to increased risk of IVH. Inflammatory effects on letoplacental vasomotor tone and capillary integrity or abruption-related effects on fetal oxygenation and blood volume are possible mechanisms.