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340 SPO Abstracts

PRESSURE \lAVE CHARACTERISTICS OF THE '-"PER All) LOWER UTERINE SEGMENT IN ARRESTED LABOR. F.Margono~ A.K8rim~E.pr8kastl'and H.Minkoff .Dept .Ob/Gyn,State Universi ty of New York, Brooklyn,NY

Most methods for the measurement of uterine contractions dur­ing labor involve the use of an intrauterine pressure transduc· er OPT). Using a single IPT Seitchik found no difference in the pressure wate form characteristics of patients with suc­cessful or failed first stage of labor, either before or after oxytocin. Caldeyro Barcia stated that the intensity of the con­traction diminishes from the top to bottom of the uterus in normal labor with the upper segment of the uterus contracting more strongly than the lower. It is possible that in cases of fal led 1st stage of labor the lower segment of the uterus con­tracts more strongLy than the upper. This phenomen would not be detectable with single IPT. To investigate this possibi 1 ity two IPTs were inserted into the upper and lower segments of the uterus of laboring patients with cervical di latation of at least 4 cm who were fail ing to progress. All patients had a single term vertex fetus, and EFW <4000 g. There were 3 primi­paras and 5 rultiparas. The location of the IPT tips was con­firmed by ultrasound, both intrauterine pressure wave patterns were recorded s ifllJl taneousl y .. Management of labor was based upon the pattern of the upper segment and labor progress. 3 patients underwent cesarean section for fai lure to progress. Prel imenary analysis of the intrauterine pressure wave forms [table 11 showed that those who underwent cesarean section had higher intrauterine pressures in the lower segment than the up· per segment. The remaining patients showed greater pressures in the upper segment. Oxytocin increased intrauterine pressure in both upper and lower segments but did not change the gradient between segments .. If these data are confirmed, pressure gradi­ents may be used to gauge the l ikel ihood of success of pitocin.

Table 1: Active Pressure Integral pre and post oxytocin

NSVD (P~~~9~~~ 2~~;t~.45 (P~~~~+~~r 2.47~~~:~ CS 2.2(0.25 2.84:0.65 3.22:0.36 3.80:0.32

PREGNANCY AFTER CESAREAN SECTION: RESULTS FROM A SINGLE CENTER. Steven A. Frtedman. MD.' ~ L. Cammarano. MD.' Russell K. Laros. MD. Department of Obstetrics. Gynecology ahd Reproductive Sciences. University of California. San Francisco (UCSFI. San Francisco. California

We conducted a retrospective review of the UCSF Perinatal Database to detennlne whether an attempted trial of labor (TOL) after previous cesarean section Is more desirable than an elective repeat cesarean section (ECS). Inclusion criteria were previous c"sarean section. birth weight ;,750 g. and delivery at UCSF between I June 1976 and 31 December 1990. A total of 589 patients (including 8 with twin gestations) mel these criteria. Three hundred six (52%) had an ECS and 283 (48%) had a TOL. of whom 177 (63%) delivered vaginally. The two groups were similar In age. parity. geslalional age. and birth weight. Results are expressed as means±SD. Significance Is defined as P<,05.

TOL (SVD & CS)

Endometrllis (%) Hospital stay (d) t. Hematocrit (vol %) Transfusion (%) 5·mln Apgar ~6 (%) Umbilical artery pH Neonatal Intensive care (%)

3.9 3.5±2.2 -4.9±4.5

2.5 4.5

7.25±0.08 7.7

ECS

5.9 5.51:3.1 -3.2±3.3

1.6 2.6

7.26±0.07 8.1

PValue

NS <'(lOO5 <'(l005

NS NS NS NS

There were no malernal deaths nor uterine ruplures. Allhough stalistlcally significant. the greater fall In hematocrit In lhe TOL group Is clinically unimportant. These data support the American College of Obstetricians and Gynecologists· recommendation that a woman with a single previous cesarean section "be counseled and encouraged to attempl labor In her current pregnancy,"

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January 1992 Am J Obstet Gynecol

DILAPAN PLUS PROSTAGLANDIN E2 VAGINAL GEL FOR CERVICAL RIPENING. Andrew Chao, David Plourdx, Mai-Anh Doanx. Dept. Ob/Gyn, Santa Clara Valley Medical Center, San Jose, CA

We compared Dilapan dilators plus prostaglandin E2 (PGE2) gel to PGE2 alone. Third-trimester induction patients with Bishop scores <5 were randomly assigned. Group 1 (n=25) received 1-6 dilators (median, 5) plus 3 mg PGE2 gel. Group 2 (n=37) received gel alone. Dilators were removed in 4 hours. One or two more PGE2 doses were applied at 4-hour intervals if the Bishop score was still <5; then oxytocin was begun. Parity, gestational age, and initial Bishop scores were comparable. Group 1 had a greater increment of Bishop score at 4 hours (median 3, range 0-11 vs. median 1, range 0-9; p <0.05). However, the insertion-to­complete-dilatation intervals did not differ significantly (1267 min ± 638 SD vs. 1240 ± 549), nor did cesarean rates. Furthermore, the amnionitis/endometritis rate was higher in Group 1 (44% vs. 8%). This trial failed to justify the combined use of Dilapan and PGE2·

_PIICJIETRIC IDlRELATES Of CEPHALOPELVIC DI_HIII. R.N. Pollackx , L. Go I dstonex , MY. Divon. Dept Ob/Gyn, The Albert Einstein College of Medicine, Bronx, NY.

The significant contribution of labor abnormalities to the i ncreas i ng I1I..ITber of cesarean sect i ons has focused interest on the diagnosis and management of these conditions. Morphometric factors associated with cephalopelvic disproportion (CPO) have reportedly included maternal height, weight and shoe size, as well as fetal macrosomia and macrocephaly. A sin.,le antenatal predi ctor of CPO wh i ch integrates both materna l as we II as fetal morphometric parameters has yet to be described. ~ To ascertain if the ratio of maternal height to fetal size is altered in pregnancies c"""l icated by CPO. Method: 60 patients del ivered by cesarean section (cIs) for active phase labor disorders and 138 matched controls who had spontaneous vaginal del iveries were cDq)Brect. Morphometric parameters studied included maternal height, maternal weight, maternal body mass index (BMI) and syq>hyseal fundal height (SFH). A parameter which relates fetal size to maternal height was defined as the Maternal·Fetal Ratio [MFR = Maternal Ht (cms) + Syq>hyseal Fundal Ht (cms)). Results: A significant correlation between the presence of an abnormal MFR (defined as MFR < 4.00) and del ivery by cesarean section for active phase labor disorders was observed (p < 0.000001). The odds ratio (OR) of a patient with an abnormal MFR having a cesarean section for an active phase labor abnormal ity was 5.08 (95% CI = 2.6 • 10.0). As previously observed short maternal stature was also associated with an increased rate of cIs for active phase labor disorders. The OR of a patient < 160 cms. tall having a cIs for an active phase labor abnormalities was 2.21 (95:t. CI = 1.17 - 4.17). Maternal weight and 8MI were not significantly correlated with delivery by cIs for labor abnormal ity. ConcLusion: Of the various parameters studied, an abrlormal MFR was most significantly correlated with del ivery by cIs for active phase labor disorders. Prospective evaluation of the maternal fetal ratio in the prediction of CPO may be indicated.