376 SPO Abstracts

280 THE EFFICACY OF ORAL TERBUTALINE FOLLOWING PARENTAL TOCOLYSIS FOR PRETERM LABOR. B. Parilla'. S. Dooley, M. Socol. Dept of Ob/Gyn, Northwestern Univer~cal School, Chicago, II.

OBJECTIVE: To investigate in a prospective randomized study. t~e efficacy of oral terbutaline after successful paranteral tocolysls In reducing recurrent preterm labor and praterm bIrth. . . STUDY DESIGN: Patients admitted to the maternal-fetal medIcIne service between 28-34 weeks' gestation with uterine contractions and progressive cervical dilation were treated with IV MgSO, for 12-24 hours. After successful tocolysis patients were approached for study participation and randomized to receive either oral terbutaline or no therapy. The dose of terbutaline was individualized. to achieye a maternal pulse > 100 bpm and terbutaline was contInued until 36 completed waeks of gestation. Recurrent PTL (contract.ions with changa in cervicel examinetionl for either group wes treeted ":'I"h IV MgSO, ~nd subsequent treatment was based on prevIous randomization. AS8uml~g e p error of 0 .2, a power calculation determiMd that 23 patients In each group were rsquired to detect 8 2 week difference In gsstatwnal age at delivery.

RESULTS: T erbutaline (n-231

GA upon entry Iw_.1 31.6 ± 3.3 Oil on admiSSIon leml 2.7 ± 0.6 Cervical length on adm leml 1.1 ± 0.5 Delivary > 37 weeks 8 GA at delivery 35.8 ± 2.5 Birth weight Igml 2679 ± 632 Recurrent PTL 7 Recurrent contractions· 4 Neonetal RDS 3

No therapy (0=221

31.5 ± 1.8 2.3 ± 0.9 1.1 ± 0.7

10 36.3 ± 2.2 2688 ± 638

3 6 1

·observation without change in cervical examination

P

0.903 0.054 0.801 0.465 0.485 0.962 0.135 0.510 0.633

A multiple stepwise linear regression was performed using preterm delivery « 37 wksl as the dependent variable .. I,:,~epend~nt variables related to outcome were GA at entry (r= .391, Imllol dilation (r=:3~), ond history of preterm delivery Ir=.27). Maternal age, Inlllal effacement recurrent PTL, and terbutaline were not related to outcome. CONCLUSIONS: The use of oral terbutaline after successful parenteral tocolysis failed to reduce preterm birth or recurrent PTL.

281 A RANDOMIZED PROSPECTIVE STUDY OF INTRAVENOUS MAGNESIUM SULFATE, RITODRINE, AND SUBCUTANEOUS TERBUTALINE AS TREATMENTS FOR PRETERM LABOR A. Sciscione.' R. Gorman.' P. Schlossman. G. Colmorgen, Department of Ob/Gyn, Medical Center of Delaware. Newark, DE. OBJECTIVE: Assess the relative effectiveness of intrevenous (IV) magnesium sulfate, IV ritodrine, end subcutaneous ISO) terbutaline as treatments for preterm labor. STUDY DESIGN: One hundred thirty two pregnant women diagnosed as experiencing preterm lebor with intact membranes at 20 to 36 weeks gestation were randomized to treatment with standard doses of IV magnesium sulfate, IV ritodrine, 50 terbutaline. Treatment failure was defined as progression of labor or significant side elfect tdespite administration at a lower dose) . Patients who failed magnesium sulfate were switched to 8 betamimatic . Patients who foiled betamimetics were switched to magnesium sulfate. All undeliverad patients were discharged with an oral tocolytic agent. The data was analyzed using chi-squared anelysis. RESULTS: The groups were found to be statistically similar with regard to face, gestational ago, gravidity, parity, abortions, tobacco use, dilatation and initial Bishops scors. Patients treated with ritodrine were more likaly to fail tocolysis 144.7%) than those treated with magnesium sulfate 117.3%1 orterbutaline 111.9%) Ip=O.OO1). Even when failures secondary to side effects were eliminated, terbutaline and magnesium sulfete were less likely to fail than ritodrine Ip - 0.031). Delay in delivery of 48 hours while not statistically different batween the agents, Ip = 0.081 was higher in the terbutaline and magnesium groups. CONCLUSIONS: Treatment of pre term labor with IV ritodrine is less successful than treatment with IV magnesium suit ate or sa terbutaline .

282

283

January 1993 Am J Obslel Gynewl

A COMPARISON OF MgS04 AND INDOMETHACIN TO Mg504 ONLY FOR TOCOLYSIS IN PRETERM LABOR WITH ADVANCED DILATION. A.. Grimshaw x OF. Lewis. GG. Brooksx. DR.

Dunnihoox• C. Baxterx . Dept of Ob/Gyn. LSU Medical Center. Shreveport, LA. OBJECTIVE: The greater that the caIVix is dilated, the more difficult it becomes to obtain a successful tocolysis. Some physicians do not even attempt tocolysis when the caIVix is over 3 cm dilated. The purpose of this study was to assess the success of tocolysis using a single versus a double agent when the cervix was greater than 3 em dilated. STUDY DESIGN: A retrospective analysis was undertaken to assess the suocess of tocoIysis in all patients in whom preterm labor had occurred in which there was no known etiology between 1189 and 6/92 and who had their carvix dilatad .. 3 em. Patients received MgS04 only, or MgS04 and Indomethacin. RESULTS: The following table illustrates the results.

MgS04 & Indomelhacin MgS04

Number 21 23 Age 22.2 ± 5.5 21.4 ± 4.6 Gravidity 2.5 ± 1.9 3.04 ± 2.2 Max Mg cone. (mg/dl) 6.96 ± 1.8 6.61 ± 1.2 Dilation aUocolysis (cm) 3.56 ± 1.0 3.49 ± 1.4 Effacement atlocolysis 87.3 ± 17.4 88.0 ± 15.4 No. delayed ~ 48 hours 17 12. No. with oervix ~4 em 9 9 EGA attocofysis 27,1 ± 2.4 31 .0 ± 2.4· Delay in delivery (hrs) 368.3 ± 346 70.9 ±92.9·

, = P = 0.09 • = P < O.OOOt

Patients who received tocolysis with both MgS04 and Indomelhacin were earlier in gestation. No matemal complications occurred in eilher group. CONCLUSION: Dual agent tocolysis with MgS04 and Indomethacin appears to be a safe effective method of tocolysis with advanced dilation especially in those pregnancies remote from term.

TERBUTALINE LEVELS DURING TOCOLYSIS VIA PORTABLE PUMP_ ~,J. Belluominix, F. Lamx, R. KlotzX, R. L~tx. Dept. of Ob/Gyn, Cal Pac Med Cntr, San Francisco, CA. OBJECTIVE: In recent years, the administration of subcutaneous Terbutaline tocolysis via small, programmable, portable pumps, ca­pable of continuous as well as bolus infusions, has gained accep­tance. However, data concerning serum concentrations of Terbutaline during this mode of therapy are lacking and are the subject of this report. STUDY DESIGN: Bolus Group A (n _ 4) : Samples just prior to a bolus infusion and then at intervals of 5 , 10, 15,20, 25, 35, 45, 60, 90, 120, 180,240,360 and 480 minutes. This determined timing and value of peak level, and time interval back to baseline. Chronic Group B (n _ 13): Samples at : ;a24 hrs (Basal a) ; basal pre-bolus (Basal b) ; 25-30 min post bolus (Peak);;a 1 week (Basal c). RESULTS:

I:: ~=A : 1 • • r : i :4 1.... ·~-..... :;; ... r:---;;;;;;""-"UU1:"t .-

CONCLUSIONS: 1) Post bolus peak serum Terbutaline values occur w~hin 20-30 minutes and return to baseline levels within 90-180 minutes. These are similar to those observed after a single intrave­nous dose both in timing and in levels. 2) The steady state Terbutaline levels in our study patients Were lower than those observed during intravenous therapy and resemble those seen during low dose (2.5 mg) oral administration. 3) No appreciable change in serum concen­trations was observed after long term administration.