328 SPO Abstracts

99 ADENOSINE IN THE HUMAN FETUS. CP Weiner', G Power"', Y

Yoncyama"'. Depta. Ob/Oyn, Univ. of Iowa', Iowa City, IA and Loma Linda

Univ:, Loma Linda, CA. OBJECfIVE: Adenosine is a potent dilator of several vucular beds and may

be involved in hypoxemic vasodilation. In intact sheep fetuses, adenoline

dilate. pial arterioles. Since the fetus is relatively hypoxemic (normal total

oxygen content (fOC) < 16 mI/dL), we hypothesized that the concentration of

adenosine in the human fetus would be elevated and inversely related to oxygen

content.

STUDY DESIGN: We tested this hypothesis by measuring adenosine (pM/L)

in blood specimens from 33 fetuses obtained at a clinically indicated

cordocentcsis and then determining ita relationship to ge&tation, Mh, UVpH,

UVpC02, UVp02 and the calculated roC.

RESULTS: Gestation ranged from 21-41 weeks (mean 30±5 wk). Fetal

hemolytic disease was the most common indication; overall the Hb ranged

from 5.8-17.4 g/dL (mean 12.3±3 g/dL). No fetus was growth deficient.

Adenosine ranged from 0.19 to 2.7 I'M/L (1.01 ± .6I'MIL). The distribution

was remarkably tight with the one low value occurring in a fetus with triploidy.

There was no relationship between adenosine and either gestation, roc or any

of the blood gas measurements. However, there was a significant positive

relationship between adenosine and Hb (r=0.5 I, P =0.005). There was a trend

for lower adenosine concentrations in fetuses with hemolytic disease (1.22±.8

vs. O. 79± .27, p =0.06), but the correlation between adenosine and Hb held

after excluding fetuses with hemolytic disease.

CONCLUSIONS: This first investigation of adenosine in the human fetus

demonstrates that: a) adenosine circulates without gestational age effect; b) is

not related to oxygen in appropriately grown fetuses; and c) is lower in anemic

fetuses perhaps as a reflection of decreased viscosity.

100 FETAL SERUM ,.·MICROGLOBUUN IS A POSSIBLE INDICATOR OF In _ RENAL FUNCTION. RS Smith', SM Berry, K Kithier", KS Puder", MP Dombrowski, DB Cotton. Department of Obstetrics & Gynecology, Wayne State University/Hutzel Hospital. Objectlv.: Case selection for shunt placement in fetuses with obatructive uropathies has been based on urinary P2-microglobulin 1P2M), electrolytes, and sonogrephic parameters. P2M does not appreciably cross the placanta. Our goal was to determine if fetal serum P2M is a useful indicator of in utero renal function. Study DMlgn: P2M was measured In 23 cordocentesis samples from pregnancies with e gestational age range of 19 to 37 weeks. Fetal blood sampling was performed for a variety of indications unrelated to this study. This group had normal amniotic fluid volume and no detectable urinary tract anomalies. Serum values and gestational age were evaluated using simple regression analysis. Comparisons were made between this group and an abnormal group of 6 fetuses; 3 with idiopathic oligohydramnios, 1 fetus with an obstructive uropathy, and 2 fetuses with renal agenesis. R •• ult.: The mean gestational age and P2M levels of the 23 fetuses were 27.9 ± 6.3 weeks and 3.4 ± 0.6 pglml respectively. P2M in this group decreased with advancing gestation (r = -0.62, P s 0.01). The abnormal group's P2M = 7.2 ± 3.1; P < .01. Values of 8.3 and 8.4 were found in the fetuses with renal agenesis. The fetus with obstructive uropathy had a P2M level of 3.7; at birth this neonate had prune belly syndrome and normal renal function. Conclu.ion.: Serum P2M levels appear to decrease with increasing gestational age. We attribute this to the normal increase in proximal tubule reabsorption and increased metabolism. Elevated levels may be found in fetuses with structural renal abnormalities or idiopathic decreased renal function. Our data suggests that this marker can be a useful way to assess in utero renal function.

January 1993 Am J Obstet Gynecol

101 CARDIAC DOPPLER VELOClMETRY AND ACID BASE BALANCE

IN IUGR FETUSES. E. Ferrazzi, M. Bellotti, A.M. Marconi, L. Hisi,

A. Barbera and G. Pardi. Dept. Ob/Gyn 18BM San Paolo, University

102

of Milan, Italy. OBJECTIVE This study analyzes the correlations between aortic,

pulmonary and ductal peak velocities of growth retarded (IUGR) fetuses

and intrauterine values of lactic acid, pH, pC02 and oxygen content

STuoY DESIGN 29 IUGR fetuses with abnormal umbiliea1 pulsatility

index were included in the study. In all these fetuses aortic, ductal and

pulmonary peak velocities were measured before percutaneous umbilical

blood sampling (PUBS). A pulsed doppler equipment guided by color

flow imaging was used. Normal standards were obtained on 110 normal

pregnancies as a function of estimated fetal weight. Lactate

concentration, pH, pe02 and oxygen content were measured.

RESULTS The mean gestational age at PUBS was 31W weeks. The

mean gestational age at delivery was 33 ±3 weeks; the mean weight was

1403+581. Aortic, ductal and pulmonary peak velocities found in IUGR

fetus;' were significantly lower (p < .002) than in normal fetuses of

comparable weight. The severity of this reduction was significantly

correlated with the degree of asymmetricity of IUGR (p< .0001; r=.65).

A significant prevalence of high lactate concentrations (p < .003) and low

oxygen content (p < .03) were found in fetuses with abnormal peak

velocities. All fetuses with aortic peak velocities below 20 % of lower

reference values were acidaemic. The correlations of pH and pC02 did

not reach a statistical significance CONCLUSIONS Acid base and oxygen content observed at PUBS

provide a direct evidence that, in thelUGR'human fetus, low cardiac

velocimetry is associated with a significant risk of feto~placental

metabolic acidaemia and hypoxemia and an impaired exchange of pC02.

MATERNAL AND, NEONATAL PLATELET PHYSIOLOGY AA Saleh 1M O'Brien', AR Mun\wab', MP Dombrowoki, SF Bottoms, DB Cotton, ODd EF Mommenx

• Depmment of Ob/Gyn, Wlyne State Univ .... ity/Grace ODd Hutzel Hospitoll, Detroit, MI

OBJECTIVE: NeoDllal pillelet phYliology il _ well undentood. While plotelet rich pluma (PRJ') l8JRPIion il poor, neoDllal blcedi11ll times .... molter thlD in children ODd adultl. Newer pillelet oggregotion teIIl employi11ll the principle of impedance rangea (0111110) in whole bloOd may repreaent the in vi"" environment more cloooly. A recently developed iDllrument (Thromb08lal 40(0) measuri11ll platelet aahesioD? aggregation and fol'OW.ion of the lint hemostatic plug in citrated whole bloOd his _ yet been used to study newborns ODd mothen.

STUDY DESIGN: We measured Thrombostat times, pll,elet COUR'. (PLC), mean plotelet volumes (MPV), fibronectin (FN), ODd von Willibrsnd Factor (VWF) levels in 19 poin of maternal ODd cord bloOd I101I1ples immediately after delivery. In 11 poin we meaaured whole bloOd aggregltion, ODd UIOCioted ATP rei .... with ADP ODd collagen. Paired MANOVA WIS used for llatistical anaIy.il, with p < 0.01 considered .ignificant.

RESULTS:

Thrombostat (sec) PLC (thoussnd/mm) MPV(p) FN (Pi/mI) VWF(%) ADP Aggregotion

-OOml - ATP rei .... nMole

Collagen Aggregotion

Moterna\ 83 ± IS 130 ± 66 9.3 ± 1.5 2S9± 95

379 ± 141

5.8 ± 4.4 1.2 ± 0.8

Cord BloOd 59 ± 10

226 ± 76 8.3 ± 1.5 130 ± 15 219 ± 60

3.5 ± 5.4 0.66 ± 0.6

P <0.0001 <0.0001 <0.005 <0.001 <0.0001

N.S. <0.005

-ooms 24.6 ± 11.8 20.6 ± 7.1 N.S. -ATPreiCIICnMole 2.7±2.7 2.7±3.3 N.S.

CONCLUSION: The combination of morter Thromb08lal times but normal aggregltion in cord bloOd implies increased·plltelet adh .. ivencsl. Decreased levels of two plotelet adhesive proteins, FN ODd VWF, suggest the possibility of increased receptor profiles on the platelet .. rface or intenction with other blood component •. Increased plotelet adh .. iv ...... could be I factor in the tendency for thrombosis _ed in neonates despite low procoagulant factors.