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245 Is this cervix inducible? The neural network solution
314
spa Abstracts
244 UTERINE RUPTURE IN THE PATIENT UNDERGOING A TRIAL OF LABOR AFTER CESAREAN SECTION. Richard M. Fanner, MD, PhOX, Thomas Kirshbaum, MDx, Daniel PotterX , Thomas H. Strong, MD, University of Southern California, L.A., CA. Due to a variety of medical , financial , and personal circumstances, vaginal birth after a previous cesarean section (VBAC) has become an increasingly common therapeutic option. This study was undertaken to determine the incidence and associations of uterine rupture/dehiscence with an attempted VBAC . The charts from 144 patients determined to have had a uterine rupture/dehiscence from 1983 to 1989 were examined. During this time period their were 119,395 total deliveries at LAC+USC Women's Hospital, with 11,041 patients presenting with a history of a previous cesarean section (CS). 7,598 patients underwent a trial oflabor, with 6,021, or 54.5%, delivering vaginally. The uterine rupture rate was found to be 1.0% (77 cases) , whIle the uterine dehiscence rate was 0.9% (67 case s). The traditional hallmarks of rupture, pain and bleeding, were found to occur in only 5.2% and 13.0% of the rupture patients respectively. Fetal bradycanha leading to operative intervention was the most common finding, occunng In 49.0% of the rupture patients. 60.4% of the patients with a rupture/dehiscence had oxytOCIn administered during their labor, and 45.8% of the patients with a rupture/dehiscence fell below the 5 th percentile on the Friedman labor curve. We conclude that, although the incidence of uterine rupture is low, the event is most often acute. Prevention might be directed toward the active diagnosis and avoidance of dystocia disorders. Staff and facilities available for safe management of rupture/dehiscence are a requisite for the conduct ofVBAC.
245 IS THIS CERVIX INDUCIBLE? THE NEURAL NETWORK SOLUTION. Richard M. Fanner, MD, PhOX, Arnold L. Medearis, MD, Anna S. Leungx, MD. Umverslty of Southern California, L.A., CA. Prediction of a successful labor inductIOn in the postdates patient has relied on the categorizatio n of the cervical examination by utilizing the Bishop's score (BS). ABS > 6has been sufficient indication for induction of labor, With a n expectation of a relatively high cesarean section (CS) rate for failed induction considered acceptable. The BS as initially described was based on the pattern recognition that components of the cervical exam were related to a higher rate of vaginal deliveries. When the fetus is not at risk, selection of the factors associated with a failed induction should lead to a lower CS rate if those pregnancies could be prolonged untill successfu l induction was predicted. Pattern recognition is the forte of the biologically simulated intelligence (BSI), or neural network. Its applicability to a postdate population was evaluated by a retrospective analysis of 297 pregnancies undergoing induction, of which 198 had a Bishop's score> 6. 232 pts were used to develop the network model , with tlie model tested in the 65 remaining pts. The variables analyzed were the BS (with its components), age, gravidity, parity, fetal weight, and gestational age. The optimal network model was iterated with respect to the number of neurons, training tolerance, and neuron gain. Within the subgroup of65 patientsts used to validate the model, the CS rate was 13.8%. By correctly identifying 7 of 9 failed inductions, with theIr subsequent exclusion, the CS rate in the induction population would be lowered to 3.4%. The positive predictive value of the network for a vafinal delivery was 95.8%hwith a negative predictive value 0 41.2%. We conclude t at the predictive ability of the BS can be significantly improved by adding clinical variables within a neural network model. It appears that the BSI technique may enhance clinical management and that prospective validation is needed.
.I.lIluan 199 1 Am J Obstet G) necol
246
TRANSVAGINAL CERCLAGE UNDER SONOGRAPHIC GUIDANCE IN CASES OF SEVERE CERVICAL HYPOPLASIA J Lydmjr MD, GM Jackson, MD, I Forouzan, MD~ P Samuels, MD Universrty of Pennsylvania Medical Center, Philadelphia PA Transabdominal cervical cerclage has been advocated for patients with cervical incompetence whose cervix is so short that rt appears flush against the vagll1al wall. Anhough small series of successful transabdominal cerclages have been reported, the morbidity of thiS technique precludes its routine use. We descClbe here three patients with recurrent 2nd-trimester pregnancy loss who underwent successful prophylactic transvaginal cerclage placement between 12-14 weeks gestation. Two patients had a history of in-utero DES exposure and one patient had undergone two cervical conizations. All patients had a cervical length of less than 0.5 ern, and on examination rt was difficun to clearly ident~y a cervical margin. Under regional anesthesia, each patient had transabdominal sonographic confirmation of gestational age and viability, then the lower uterine segment and internal cerVical os were identified. Under unrasound gUidance, the anterior lip of the cervix was identified and a silk stay suture was placed for traction. Vaginal tissue circumscribing the cervical lip was dissected free with a scalpel. Two nonabsorbable sutures were placed through the cervix in cross fashion from 12 to 6 o'clock and from 9 to 3 o'clock under constant unrasound guidance, in a modification of the Wurm technique. The dissected vaginal tissue was brought back on top of the cerclage and closed with interrupted 00 chromic gut suture. All three patients had an uncomplicated postoperative course and went to term, delivering by cesarean section We feel that the use of ultrasound in cases of severe cervical hypoplasia may allow transvaginal cerclage placement, obviating the need for abdominal cerclage placement and its increased morbidity.
247
ADVERSE PREGNANCY OUTCOME IN DESEXPOSED PREGNANT WOMEN MANAGED BY A HIGH RISK OBSTETRIC PROTOCOL
.! ~ P Samuels, C Lindenbaum, A Cohen, MT Mennutl University of Pennsylvania Medical Center, Philadelphia Pa Poor pregnancy outcome has been reported in as many as 58% of women exposed to DES in utero. We previously reported our experience with 63 gravid patients managed with the following aggressive protocol: a) decreased activity; b) weekly cervical evaluation by digital exam andlor sonography; c) cerclage for patients with a history of loss, cervical hypoplasia or cervical change during gestation; d) uterine contraction monitoring ; and e) education regarding preterm labor. We now review the outcomes of 123 pregnancies, 85 of whom underwent cerclage, managed by this protocol. All patients had fetal viability demonstrated by unrasound after 10 weeks gestation. A living infant was delivered by 116 (94%) patients, with 101 (82%) delivering after 36 weeks. Seven patients (6%) experienced a perinatal death at a mean gestational age of 23.3 ± 3.6 weeks with a mean birthweight of 525.2 ± 72.3 gm. All losses were associated with premature rupture of membranes (PROM) in the absence of demonstrable preterm labor or cervical change. Five losses were in patients without cerclage, and 2 occurred in patients with a cerclage for a history of mid-trimester loss (p< 0.05 by Fisher's Exact Test). Conclusions: 1) Aggressive management of the DES-exposed gravida usually results 111 a good pregnancy outcome. 2) A small number of DES-exposed patients experience PROM and perinatal loss without evidence of preterm labor or cervical change, in spite of intenSive obstetrIC management. 3) Although clearly controversial, cerclage statistically lowers the risk of PROM.
spa Abstracts
244 UTERINE RUPTURE IN THE PATIENT UNDERGOING A TRIAL OF LABOR AFTER CESAREAN SECTION. Richard M. Fanner, MD, PhOX, Thomas Kirshbaum, MDx, Daniel PotterX , Thomas H. Strong, MD, University of Southern California, L.A., CA. Due to a variety of medical , financial , and personal circumstances, vaginal birth after a previous cesarean section (VBAC) has become an increasingly common therapeutic option. This study was undertaken to determine the incidence and associations of uterine rupture/dehiscence with an attempted VBAC . The charts from 144 patients determined to have had a uterine rupture/dehiscence from 1983 to 1989 were examined. During this time period their were 119,395 total deliveries at LAC+USC Women's Hospital, with 11,041 patients presenting with a history of a previous cesarean section (CS). 7,598 patients underwent a trial oflabor, with 6,021, or 54.5%, delivering vaginally. The uterine rupture rate was found to be 1.0% (77 cases) , whIle the uterine dehiscence rate was 0.9% (67 case s). The traditional hallmarks of rupture, pain and bleeding, were found to occur in only 5.2% and 13.0% of the rupture patients respectively. Fetal bradycanha leading to operative intervention was the most common finding, occunng In 49.0% of the rupture patients. 60.4% of the patients with a rupture/dehiscence had oxytOCIn administered during their labor, and 45.8% of the patients with a rupture/dehiscence fell below the 5 th percentile on the Friedman labor curve. We conclude that, although the incidence of uterine rupture is low, the event is most often acute. Prevention might be directed toward the active diagnosis and avoidance of dystocia disorders. Staff and facilities available for safe management of rupture/dehiscence are a requisite for the conduct ofVBAC.
245 IS THIS CERVIX INDUCIBLE? THE NEURAL NETWORK SOLUTION. Richard M. Fanner, MD, PhOX, Arnold L. Medearis, MD, Anna S. Leungx, MD. Umverslty of Southern California, L.A., CA. Prediction of a successful labor inductIOn in the postdates patient has relied on the categorizatio n of the cervical examination by utilizing the Bishop's score (BS). ABS > 6has been sufficient indication for induction of labor, With a n expectation of a relatively high cesarean section (CS) rate for failed induction considered acceptable. The BS as initially described was based on the pattern recognition that components of the cervical exam were related to a higher rate of vaginal deliveries. When the fetus is not at risk, selection of the factors associated with a failed induction should lead to a lower CS rate if those pregnancies could be prolonged untill successfu l induction was predicted. Pattern recognition is the forte of the biologically simulated intelligence (BSI), or neural network. Its applicability to a postdate population was evaluated by a retrospective analysis of 297 pregnancies undergoing induction, of which 198 had a Bishop's score> 6. 232 pts were used to develop the network model , with tlie model tested in the 65 remaining pts. The variables analyzed were the BS (with its components), age, gravidity, parity, fetal weight, and gestational age. The optimal network model was iterated with respect to the number of neurons, training tolerance, and neuron gain. Within the subgroup of65 patientsts used to validate the model, the CS rate was 13.8%. By correctly identifying 7 of 9 failed inductions, with theIr subsequent exclusion, the CS rate in the induction population would be lowered to 3.4%. The positive predictive value of the network for a vafinal delivery was 95.8%hwith a negative predictive value 0 41.2%. We conclude t at the predictive ability of the BS can be significantly improved by adding clinical variables within a neural network model. It appears that the BSI technique may enhance clinical management and that prospective validation is needed.
.I.lIluan 199 1 Am J Obstet G) necol
246
TRANSVAGINAL CERCLAGE UNDER SONOGRAPHIC GUIDANCE IN CASES OF SEVERE CERVICAL HYPOPLASIA J Lydmjr MD, GM Jackson, MD, I Forouzan, MD~ P Samuels, MD Universrty of Pennsylvania Medical Center, Philadelphia PA Transabdominal cervical cerclage has been advocated for patients with cervical incompetence whose cervix is so short that rt appears flush against the vagll1al wall. Anhough small series of successful transabdominal cerclages have been reported, the morbidity of thiS technique precludes its routine use. We descClbe here three patients with recurrent 2nd-trimester pregnancy loss who underwent successful prophylactic transvaginal cerclage placement between 12-14 weeks gestation. Two patients had a history of in-utero DES exposure and one patient had undergone two cervical conizations. All patients had a cervical length of less than 0.5 ern, and on examination rt was difficun to clearly ident~y a cervical margin. Under regional anesthesia, each patient had transabdominal sonographic confirmation of gestational age and viability, then the lower uterine segment and internal cerVical os were identified. Under unrasound gUidance, the anterior lip of the cervix was identified and a silk stay suture was placed for traction. Vaginal tissue circumscribing the cervical lip was dissected free with a scalpel. Two nonabsorbable sutures were placed through the cervix in cross fashion from 12 to 6 o'clock and from 9 to 3 o'clock under constant unrasound guidance, in a modification of the Wurm technique. The dissected vaginal tissue was brought back on top of the cerclage and closed with interrupted 00 chromic gut suture. All three patients had an uncomplicated postoperative course and went to term, delivering by cesarean section We feel that the use of ultrasound in cases of severe cervical hypoplasia may allow transvaginal cerclage placement, obviating the need for abdominal cerclage placement and its increased morbidity.
247
ADVERSE PREGNANCY OUTCOME IN DESEXPOSED PREGNANT WOMEN MANAGED BY A HIGH RISK OBSTETRIC PROTOCOL
.! ~ P Samuels, C Lindenbaum, A Cohen, MT Mennutl University of Pennsylvania Medical Center, Philadelphia Pa Poor pregnancy outcome has been reported in as many as 58% of women exposed to DES in utero. We previously reported our experience with 63 gravid patients managed with the following aggressive protocol: a) decreased activity; b) weekly cervical evaluation by digital exam andlor sonography; c) cerclage for patients with a history of loss, cervical hypoplasia or cervical change during gestation; d) uterine contraction monitoring ; and e) education regarding preterm labor. We now review the outcomes of 123 pregnancies, 85 of whom underwent cerclage, managed by this protocol. All patients had fetal viability demonstrated by unrasound after 10 weeks gestation. A living infant was delivered by 116 (94%) patients, with 101 (82%) delivering after 36 weeks. Seven patients (6%) experienced a perinatal death at a mean gestational age of 23.3 ± 3.6 weeks with a mean birthweight of 525.2 ± 72.3 gm. All losses were associated with premature rupture of membranes (PROM) in the absence of demonstrable preterm labor or cervical change. Five losses were in patients without cerclage, and 2 occurred in patients with a cerclage for a history of mid-trimester loss (p< 0.05 by Fisher's Exact Test). Conclusions: 1) Aggressive management of the DES-exposed gravida usually results 111 a good pregnancy outcome. 2) A small number of DES-exposed patients experience PROM and perinatal loss without evidence of preterm labor or cervical change, in spite of intenSive obstetrIC management. 3) Although clearly controversial, cerclage statistically lowers the risk of PROM.