234

235

Volume 168 Number I, Part 2

ACTIVE MANAGEMENT OF LABOR-FACTORS THAT EFFECT ROUTE OF DELIVERY. Peaceman AM, Lopez-Zeno lA, Socol ML. Dept. of Ob/Gyn, Northwestern Univ. Medical School, Chicago, Illinois. OBJECTIVE: We demonstrated previously that a unifonn protocol of Active Management of Labor (AMOL) is effective in lowering the rate of cesarean section (CS). We now evaluate maternal and fetal factors which influence the route of delivery for patients managed under AMOL. METHODS: Data were coUected prospectively on 351 consecutive patients managed by the AMOL protocol. Demographic and labor characteristics of patients undergoing CS (n=37) were compared to those having vaginal deliveries (n=314) using t-test, chi-square analysis, and multiple logistic regression. RESULTS: CS was more common for patients with station on admission higher than -1 (18.8% vs. 7.9%, p<.02); amnionitis (37.5% vs. 8.8%, p < .005); and if more than 18 mU of oxytocin were used (20.3% vs. 7.6%, p < .005). Patients receiving an epidural for labor anesthesia also had a higher incidence of CS (12.9% vs. 3.1 %, p< .01). However, the interval from admission to epidural and dilation at epidural were not different in the two groups, suggesting that epidural anesthesia was utilized more frequently once dystocia occurred rather than being the cause of dystocia. Patients delivering by CS did not differ from those delivering vaginaUy in tenns of age, race, payor status, pregravid weight, total weight gain, gestational age, birth weight, presence of rupture of membranes on admission, dilation on admission, dilation in the flrst 2 hours after admission, interval from admission to augmentation, or dilation at augmentation. CONCLUSIONS: Contrary to data reported from other labor management schemes, increased birth weight, maternal weight gain, early epidural placement, and dilation on admission do not influence the rate of CS in patients with AMOL. Success in achieving vaginal delivery is primarily related to station at admission, efficiency of uterine contractions, and the uterine response to oxytocin.

PROPHYLACTIC AMNIOINFUSION FOR OUGOHYDRAMNIOS IN TERM LABOR: A RISK FOR CHORIOAMNIONITIS. OA Ogundipex, CY SpongX, MG Ross. Dept. of OB/GYN, Harbor-UCLA, Torrance, CA. OBJECTIVE: We hypothesized that prophylactic amnioinfusion (AI) in term labors complicated by oligohydramnios will improve perinatal outcome. STUDY DESIGN: 116 term gestations with oligohydramnios (AFI .s;5.0 cm) were randomly assigned to receive prophylactic saline AI (600 cc bolus followed by 3 cclminute) or standard obstetric care (control). AI was administered as soon as an intrauterine pressure catheter was abl.e to be placed. Control patients who subsequently developed moderate or severe variable decelerations received therapeutic AI. Patients with fevers were excluded from the study. Statistical comparisons were performed using student's t test, Chi-square analysis or Fisher's exact test. RESULTS: There was no significant difference in the overall cesarean delivery (21 % vs 17%, p=0.68), cesarean delivery for fetal distress (7% vs 10%, p=0.83) or umbilical gas values between the prophylactic AI (N=56) and control (N=60) groups. The rate of chorioamnionitis was significantly increased among the prophylactic AI patients (23% vs 7%, p=0.02) although the duration of intrauterine mon~oring (8.8 hrs vs 6.5 brs, p=0.06) and time from ruptured membranes to delivery (12.3 hrs vs 14.3 hrs, p=0.51) were not different. Only 22% of the controls received therapeutic AI with one case of chorioamnionitis. CONCLUSIONS: Prophylactic AI in term pregnancies did not improve perinatal outcome but increased the risk for chorioamnionitis. Further studies are necessary on safety and efficacy of prophylactic AI for oligohydramnios at term, prior to its routine use.

236

237

SPO Abstracts 363

PROPHYLACTIC VERSUS THERAPEUTIC AMNIOINFUSION. V. Cook, JA Spinnato. Dept Ob/Gyn, Univ of Louisville, Louisville, KY. OBJECTIVE: Several articles have compared "prophylactic" amnioinfusion (AI) to no AI in the presence of variable decelerations, oligohydramnios, or thick meConium. In order to defme the optimal time to perfonn AI, the goal of this study was to determine whether prophylactic (or early) AI in the presence of oligohydramnios and before the onset of variable decelerations is more beneficial than therapeutic (or late) AI after variable decelerations or passage of thick meconium has occurred. STUDY DESIGN: Patients with intrapartum API < 10 cm (at any time) were randomized into two groups. The prophylactic AI group received a 700cc AI. When the API remained less than 8 cm, additional infusions in 250cc increments were given until an API of 10 em was achieved. The therapeutic AI group received a 700cc AI upon development of decelerations or thick meconium. If variables recurred, an additional 250cc infusion was administered. If decelerations never appeared, AI was not perfonned. RESULTS: operative delivery

c-section for: Arrest Distress Prophylactic (n~85) 6 3 Therapeutic (n=84) 8 3

Other 2 3

Forceps 8 7

Neonatal outcome: cord pH<7.20 Prophylactic 10

1 min Apgar<7 7

5 min Apgar<7 o

Therapeutic 12 13 28 of 84 (33%) patients in therapeutic group did not require AI. CONCLUSIONS: As measured by the incidence of operative delivery and condition at birth. prophylactic and therapeutic AI perfonned equiValently. This suggests therapeutic AI is the preferred technique because: it may be performed less frequently than prophylactic AI; therapeutic AI does not require API to be routinely perfonned at L&D admission; and there appears to be no harm in waiting for variables to appear if AI is promptly instituted once they develop. Prophylactic AI for oligohydramnios before variables appear has no apparent advantage over therapeutic AI for variables or meconium.

SUBSEQUENT PREGNANCY OUTCOME IN PATIENTS WITH UNREPAIRED SCAR SEPARATION. B. Leung'. A. Leung, R. Paul. Dept. Ob/Gyn, Univ. of Southern CA., School of Medicine, L.A., CA. OBJECTIVE: To determine the subsequent pregnancy outcome in patients who had unrepaired scax sepaxation following vaginal birth after cesarean (VBAC). STUDY DESIGN: Seventy five women with unrepaired scax sepaxation following VBAC from January 1, 1983 and December 31, 1991 were identified 8Jld followed. Fifteen of them had a subsequent delivery in our institution. RESULTS: The length of prior uterine scar separation noted following VBAC, number of previous cesarean section, type of previous uterine incision and mode of delivery of the subsequent pregnancy are presented as follows:

Number of patients

Length of prior uterine scar separation <4cm 13 ~5= 2

Number of previous cesarean section 1 12 2 3

Type of uterine incision low transverse 3 classical I unknown II

Route of delivery vaginal 9 cesarean 6

All but one of the prIOr unrepalred uterlOe scar separatIOn was transversely located in the low uterine segment. Eight patients underwent vaginal delivery uneventfully and were noted to have intact uterus upon uterine exploration following delivery. The patient with a prior 2 cm, low vertical unrepaired scar separation had uterine rupture and underwent hysterectomy for excessive bleeding after vaginal delivery. The indications for cesarean deliveries for the other 6 patients were: placenta previa (2), history of prior uterine dehiscence (2), cord prolapse (I) and arrest of dilatation (I). All had an intact uterus at lapaxotomy. CONCLUSIONS: Most women with a history of unrepaired scar separation will have an intact scar at a subsequent delivery. The diagnosis of scar separation following VBAC may be inaccurate or spontaneous healing may occur.