252 SPO Abstracts

23 AMNIOINFUSION IMPROVES OUTCOME IN LABOR COMPLICATED BY MECONIUM AND OLIGOHYDRAMNIOS Charles J. Macri, CDR MC USN, David B Schrimmer, MD, Anna Leung, MDx, Jeffrey S Greenspoon MD, Richard H Paul, MD. Dept. OB/GYN, University of Southern California, School of Medicine, Los Angeles, CA 90033

A prospective, randomized trial of amnioinfusion included 170 women in labor; 85 had amnioinfusion. Entry criteria were: gestational age greater than 36 weeks; thick meconium (Mec); oligohydramnios, defined as a 4-quadrant amniotic fluid index (AFI) !>. 5 cm; normal fetal heart rate pattern. An initial amnioinfusion of 500 ml saline was administered, then 250 ml increments were given as needed to maintain an AFI ~ 10.

Amnioinfusion Control :Q

Fetal distress 3 19 <0.05 Umbo pH mean (SD) 7.27 (.05) 7.22 (.09) <0.05 Mec in oropharynx 25 37 <0.05 Mec below cords 4 33 <0.05 Mec aspiration

syndrome 0 5 <0.05 C/S for distress 2 17 <0.05 These results demonstrate that amnioinfusion is an effective technique for improving the perinatal outcome of pregnancies complicated by thick meconium and oligohydramnios.

24 COMPARISON OF EXTRAOVULAR AND INTRAOVULAR UTERINE CONTRACTION MONITORING. Fadi Bsar. M.D.: Steven Warsof, M.D., Eastern Virginia Medical School, Norfolk, Virginia.

Uterine contraction monitoring is an essential part of electrOnic fetal monitoring in laboring patients. There are two universal methods of monitoring uterine contractions. The first method IS external belt monitoring. It is reliable in assessing contraction frequency, but inaccurate in evaluating intrauterine pressures. It does not however increase maternal febrile morbidity. The second method is Intrautenne contraction (lUG) monitoring with a pressure transducer. It is accurate in assessing strength of uterine contractions. It is particularly helpful in controlling oxytocin labor induction. Usually, it is conducted after spontaneous or artificial rupture olthe fetal membranes. Unfortunately, it is more often associated with maternal febrile morbidity. We devised a method of monitoring the IUC's with intact membranes, thus getting the advantages of both methods. The pressure transducer is Simply inserted between the fetal membranes and the uterus, after checking placental placement with ultrasonography. To evaluate thiS new method, a prospective randomized study was done in comparing intraovular versus extraovular IUC monitoring in patients undergoing serial labor induction with oxytocin. Study parameters Included age, weeks gestation, induction indication, obstetrical hiStOry, Bishop score, length of labor, Cesarean section rate, Apgar scores, maternal and fetal complications. Two groups of 32 patients each underwent pitocln induction, for postdates, diabetes, or hypertensive disorders of pregnancy. Our results show that extraovular IUC monitonng had better results with respect to all the parameters evaluated. Specifically, It had a shorter induction interval (p<O.05), lower C-Section rate (p<0.05), lower rate of maternal febrile morbidity (p;O 25). Otherwise the two groups were statistically identical. The technique of extraovular IUC monitoring was safe. It was similarly easy to learn and apply.

JdnUar} 1991 Am J Obstet G)llecol

25 PLASMA OXYTOCIN CONCENTRATIONS DURING GESTATION AND THE EFFECT OF AN OXYTOCIN ANTAGONIST IN PREGNANT RHESUS MONKEYS. Hirst. 1.1., x Haluska, G.l.,x Cook, M.l.,x and Novy, M.]., Oregon Regional Primate Research Center, Beaverton, Oregon.

Estrogen biosynthesis by the fetoplacental unit serves a permissive role in the induction of nocturnal uterine activity (UA) episodes. The influence of the enhanced estrogenic environment, during late gestation, on UA may involve increased maternal or fetal oxytocin (OT) secretion as well as increased uterine sensitivity to maternal OT. Therefore, we concurrently measured maternal OT concentrations at 3 h intervals and UA continuously for 36 h in 4 rhesus macaques between 128-141 days of gestation (term 167 d). Similarly, plasma OT concentrations were measured in 3 animals at 2400 h throughout late gestation. All animals were exposed to a 16 h:8 h light:dark (0700-2300 h) photoperiod. During the study period, animals displayed nocturnal UA episodes that were correlated (r=O. 76; P < 0.(01) with elevated OT concentration at 2400 h. The nocturnal UA episodes could also be blocked by infusion of an OT antagonist. There was a progressive increase in the peak OT levels observed at 2400 h, during late gestation (130-144 d, 9.8 ± 1.3 pg/ml; 144-155 d, 21.1 ± 3.3 pg/ml; 156 d-term; 34.0 ± 4. I pg/ml; P < 0.05, n=3). Infusion of OT into the fetus resulted in very high fetal plasma concentrations, but no change in maternal levels (n=3). We conclude: I) Nocturnal episodes of UA are associated with peaks of OT secretion; 2) nocturnal peaks in OT result from maternal rather than fetal OT secretion; 3) the magnitude of nocturnal OT secretory peaks increases throughout late gestation; 4) an OT antagonist is effective in blocking nocturnal UA, supporting the premise that they are OT driven events. (NIH grants HD06159, RROO163)

26 TUMOR NECROSIS FACTOR IN PRETERM AND TERM LABOR. Rarerto Romero. M.D. Mo~e Mazor, M.D. Cecili~ Avila, M.D./ SliUlChi Hanaoka, M.D., Virgini,};Sabo, M.S.N., John c;. HODbins, M.D., Diane Copeland, M.S., 10hn Williams, Ph.D., Dept. of Ob/Gyn, Yale University School of Medicine, New Haven, CT and Gen~e CoqJOration, Boston, MA.

Tumor necrosis factor-a (TNF-a) is a cytokine produced by activated macrophages capable of stimulatmg prostaglandin production by intrauterme tissues. The aims of thIS study were: 1) to determine the effect of labor (term and preterm gestation) and intraamniotic infection on amniotic fluid ,AF) concentrations of TNFa and 2) to determine the diagnostIc value of AF TNFa determinations in the diagnosis 01 intraamniotic infection. Materials and Methods: Amniotic fluid was retrieved by trans­abdominal amniocentesis from 149 women. Fluid was cultured for aerobic and anaerobic bacteria as well as Mycoplasma species. Amniotic fluid TNFa was measured with a commercially available ELISA (GenZJ!D:e Corporation Boston, MA) validated for amniotic fluid (senSItivity = 60 pwmi). Results: Normal AF from women in the second and thiro tnmesters did not contain TNFa. Amniotic fluid TNFa determinations had a greater sen­sitivity than the Gram stain examination in the detection of intraamniotic infection (92.3% [12113] vs. 61.5% [8/13J; specificity 93% vs. 100%). Moreov::,lJ, all patients with histolOgiC chorioamnionitis had detectable Tl'It<a in their AF. Women m preterm labor with positive AF cultures had significantly higher AF TNFa concentrations than those in term labor with poSItive AF cultures (median = 800 pg/ml range = 0 to 2340 pgtml vs. median = 47.5 pg/ml, ranKe = b to 815 pglml; p < 0.(01). Twenty-three ~percent (21/8;i) of women in active labor at term had TNFa in tlieir amniotic fluid; this cytokine was detected more freguently in patients with positive AF culture than in patients witli negative AF cultures (50% [7/141 vs. 20% [14/69J; p = 0.025). Conclusions: 1) Quantitation of' AF TNFa is a rapI~ sen­sitive and sJlecific test f'or the detection of intraamniotic mfection in women in preterm labor. 2) The cytokine response to microbial invaSIOn of the amniotic cavity is greater in the preterm than in the term gestation.