- Email: [email protected]
248: Whole blood hemostasis in normal pregnancy
SMFM Abstracts 245
www.AJOG.org
THE CHANGING SPECTER OF UTERINE RUPTURE RICHARD PORRECO1, STEVEN CLARK2, MICHAEL BELFORT2, GARY DILDY2, JANET MEYERS3, 1Presbyterian/StLuke’s Medical Center, Denver, Colorado, 2St. Mark’s Hospital, Salt Lake City, Utah, 3 HCA Quality Sentinel Events Committee, Nashville, Tennessee OBJECTIVE: To review all patient records discharged with codes for uterine rupture (665.04; 665.14) in a single year (2006) in HCA hospitals to determine the contemporary nature of this obstetrical complication. STUDY DESIGN: All patient charts coded for uterine rupture in HCA in 2006 were redacted, collected in one location, and distributed to a committee of perinatologists and general obstetricians. Case report forms were returned electronically and analyzed for variables of interest to determine validity of coding and quality of care. No personal identification information was available and IRB approval at the senior author’s (RP) hospital was granted. RESULTS: Sixty nine cases were identified of which only 41 were “true” ruptures; the other 28 were silent/occult dehiscenses (23), no rupture (4), and one iatrogenic perforation. In the 41 uterine ruptures, only 20 were in patients with previous cesareans and in 9 of these concurrent use of oxytocics was documented. Fifteen of previously sectioned patients had but one scar and 11 patients were attempting a VBAC; 3 had successful previous VBACs. Among the 21 patients without previous cesareans, 7 had uterine surgery of some type including instrumentation for spontaneous or elective abortion and 14 had no previous uterine manipulation of any type. Oxytocics were documented in 10 of this latter group. Standard of care breaches were identified in 10 of 41 true ruptures; 6 had no previous cesareans and 4 were attempting a VBAC. CONCLUSION: 1. Epidemiological data on uterine rupture based on hospital discharge codes without concurrent chart review are invalid. 2. Patients with previous cesareans represent only half of true uterine ruptures in contemporary practice, possibly due to better selection and/or management of VBAC patients. 3. Signs and symptoms consistent with uterine rupture (especially with concurrent oxytocics and previous uterine instrumentation) should not be dismissed in patients with unscarred uteruses.
247
EXTERNAL CEPHALIC VERSION AMONG WOMEN WITH A PREVIOUS CESAREAN SECTION: A REPORT ON 31 CASES HAIM ARIE ABENHAIM1, MARC BOUCHER2, 1Hopital Ste Justine, University of Montreal, Maternal & Fetal Medicine, Montreal, Quebec, Canada, 2Hopital Ste Justine, University of Montreal, Montreal, Quebec, Canada OBJECTIVE: Whether or not women with a previous cesarean section should be considered for an external cephalic version remains unclear. In our study, we sought to examine the relationship between a history of previous cesarean section and outcomes of external cephalic version for pregnancies above 36 weeks of gestation. STUDY DESIGN: Data on obstetrical history and on external cephalic version outcomes was obtained from the Ste-Justine Hospital External Cephalic Version Database. Baseline clinical characteristics were compared among women with and without a history of previous cesarean section. We used logistic regression analysis to evaluate the effect of previous cesarean section on success of external cephalic version while adjusting for parity, maternal body mass index, gestational age, estimated fetal weight, and amniotic fluid index at time of the version. RESULTS: Over a twelve year period, 1,151 external cephalic version attempts were made of which 31 (2.7%) were on women with a previous cesarean section. Although women with a history of previous cesarean section were more likely to be para ⬎2 (32.3% vs 14.3%), there were no difference in gestational age, estimated fetal weight, and amniotic fluid index. Women with a previous cesarean section had a similar success rate than did women without a previous cesarean section (48.4% vs 52.0%, Adjusted OR: 0.69 (0.19-2.43), p⫽0.56). CONCLUSION: Women with a previous cesarean section who undergo an external cephalic version have similar success rates than do women without a previous cesarean section. Concern about procedural success in women with a previous cesarean section should not be a deterrent to attempting an external cephalic version. 0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.261
0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.259 248 246
HIGHER MAXIMUM DOSES OF OXYTOCIN ARE ASSOCIATED WITH AN UNACCEPTABLY HIGH UTERINE RUPTURE RISK DURING VBAC ALISON CAHILL1, BRIAN WATERMAN2, DAVID STAMILIO1, ANTHONY ODIBO1, JENIFER ALLSWORTH2, BRADLEY EVANOFF1, GEORGE MACONES1, 1Washington University in St. Louis, St. Louis, Missouri, 2 Washington University in St. Louis, Missouri OBJECTIVE: Prior studies have examined the relationship between maximum oxytocin dose and uterine rupture risk in patients attempting vaginal birth after cesarean (VBAC). We sought to more precisely estimate this risk by considering timing and duration of oxytocin dose STUDY DESIGN: A nested case-control study was conducted within a multicenter, retrospective cohort study of women with at least one prior cesarean, comparing cases of uterine rupture to those who did not experience rupture (controls) while attempting VBAC. For this secondary analysis, cases and controls who were exposed to oxytocin were compared using time-to-event analysis to examine the effect of maximum oxytocin dose on the risk of uterine rupture considering therapy duration. Failure was defined as uterine rupture. Time of observation was defined as initiation of maximum dose until event. Cox proportional hazard regression was used to model the effect of maximum oxytocin dose on the risk for uterine rupture, adjusting for relevant confounding effects RESULTS: Within the nested case-control study of 792 patients, 272 were exposed to oxytocin: 62 uterine rupture cases and 210 controls. When compared to a maximum oxytocin dose range of 1-5 milliunits per minute (mu/min), increasing maximum oxytocin dose exposure was associated with a progressive increase in uterine rupture risk CONCLUSION: When the timing and duration of oxytocin dose is considered, higher ranges of maximum oxytocin dose are associated with progressively increasing risk of uterine rupture, with risk magnitude greater than previously estimated by models not considering time. This data supports a maximum oxytocin dose of 20mu/min in VBAC trials to avoid unacceptably high uterine rupture risk. Table 1 Cox proportional hazard model of effect of maximum oxytocin dose on risk of uterine rupture
WHOLE BLOOD HEMOSTASIS IN NORMAL PREGNANCY. LEONIE FLACH1, JORIS LENGLET1, FLEUR BOERSMA1, HERMAN VAN GEIJN1, ANTOINETTE BOLTE1, 1VU University Medical Center, Obstetrics & Gynecology, Amsterdam, Netherlands OBJECTIVE: Our objective is to generate reference values for rotation thromboelastometry during normal pregnancy and in the postpartum period. STUDY DESIGN: Pregnant women were recruited during their first antenatal visit of the obstetric outpatient’s clinic of the VU University Medical Center. Blood samples were taken during regular antenatal visits. Samples were taken 3 times during pregnancy at approximately 12 weeks intervals and 6 weeks postpartum. Data were analysed longitudinally per patient and by trimester: 8 - 20, 20 - 32, and 32 - 42 weeks and postpartum. Women who developed pregnancy complications were excluded from the ‘normal reference value= analysis. Thromboelastometry was performed with ROTEM® Gamma (Pentapharm GMBH, München, Deutschland). Studied are clotting time in seconds (CT), clot formation time in seconds (CFT), maximum clot firmness in millimeters (MCF), clot formation rate in degrees of the largest angle of the curve (CFR) and amplitude in millimeters after 15 and 30 minutes. Testing for intrinsic and extrinsic pathways was performed. RESULTS: A total of 78 patients were tested. Both the tests for intrinsic pathway and the tests for extrinsic pathway show a prothrombotic tendency for all parameters, except the clotting time. CONCLUSION: Prothrombotic state was found to be progressieve during pregnancy and the increase was strongest in the third trimester. By 6 weeks postpartum these changes for the greater part appear te be reversed. Results EXTEG: mean (SD)
8-20 wks 20-32 wks 32-42 wks postpartum
CFT
MCF
CFR
A 15=
A 30=
67,2 (13,0) 75,5 (11,5) 96,9 (7,5) 85,2 (7,0)
74,2 (38,5) 67,8 (2,0) 65,6 (2,0) 73,0 (2,5)
67,5 (10,5) 69,6 (1,0) 71,8 (1,5) 65,5 (3,0)
75,2 (8,0) 76,6 (0,5) 77,1 (0,5) 75,4 (1,0)
64,7 (10,5) 66,7 (1,0) 69,0 (2,0) 69,0 (2,0)
66,4 (11,0) 68,5 (0,0) 70,8 (1,0) 63,8 (2,0)
0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.262
Maximum oxytocin dose (mutran)
Hazard Ratio
95% CI
p
1-5 6-20 21-30 31-40
ref 3.34 3.92 4.57
1.01-10.98 1.06-14.52 1.00-20.85
0.047 0.040 0.050
*Significant covariates in model history of prior vaginal delivery, induction or spontaneous labor, number of prior hysterotoscies. 0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.260
S80
CT
American Journal of Obstetrics & Gynecology Supplement to DECEMBER 2007
www.AJOG.org
THE CHANGING SPECTER OF UTERINE RUPTURE RICHARD PORRECO1, STEVEN CLARK2, MICHAEL BELFORT2, GARY DILDY2, JANET MEYERS3, 1Presbyterian/StLuke’s Medical Center, Denver, Colorado, 2St. Mark’s Hospital, Salt Lake City, Utah, 3 HCA Quality Sentinel Events Committee, Nashville, Tennessee OBJECTIVE: To review all patient records discharged with codes for uterine rupture (665.04; 665.14) in a single year (2006) in HCA hospitals to determine the contemporary nature of this obstetrical complication. STUDY DESIGN: All patient charts coded for uterine rupture in HCA in 2006 were redacted, collected in one location, and distributed to a committee of perinatologists and general obstetricians. Case report forms were returned electronically and analyzed for variables of interest to determine validity of coding and quality of care. No personal identification information was available and IRB approval at the senior author’s (RP) hospital was granted. RESULTS: Sixty nine cases were identified of which only 41 were “true” ruptures; the other 28 were silent/occult dehiscenses (23), no rupture (4), and one iatrogenic perforation. In the 41 uterine ruptures, only 20 were in patients with previous cesareans and in 9 of these concurrent use of oxytocics was documented. Fifteen of previously sectioned patients had but one scar and 11 patients were attempting a VBAC; 3 had successful previous VBACs. Among the 21 patients without previous cesareans, 7 had uterine surgery of some type including instrumentation for spontaneous or elective abortion and 14 had no previous uterine manipulation of any type. Oxytocics were documented in 10 of this latter group. Standard of care breaches were identified in 10 of 41 true ruptures; 6 had no previous cesareans and 4 were attempting a VBAC. CONCLUSION: 1. Epidemiological data on uterine rupture based on hospital discharge codes without concurrent chart review are invalid. 2. Patients with previous cesareans represent only half of true uterine ruptures in contemporary practice, possibly due to better selection and/or management of VBAC patients. 3. Signs and symptoms consistent with uterine rupture (especially with concurrent oxytocics and previous uterine instrumentation) should not be dismissed in patients with unscarred uteruses.
247
EXTERNAL CEPHALIC VERSION AMONG WOMEN WITH A PREVIOUS CESAREAN SECTION: A REPORT ON 31 CASES HAIM ARIE ABENHAIM1, MARC BOUCHER2, 1Hopital Ste Justine, University of Montreal, Maternal & Fetal Medicine, Montreal, Quebec, Canada, 2Hopital Ste Justine, University of Montreal, Montreal, Quebec, Canada OBJECTIVE: Whether or not women with a previous cesarean section should be considered for an external cephalic version remains unclear. In our study, we sought to examine the relationship between a history of previous cesarean section and outcomes of external cephalic version for pregnancies above 36 weeks of gestation. STUDY DESIGN: Data on obstetrical history and on external cephalic version outcomes was obtained from the Ste-Justine Hospital External Cephalic Version Database. Baseline clinical characteristics were compared among women with and without a history of previous cesarean section. We used logistic regression analysis to evaluate the effect of previous cesarean section on success of external cephalic version while adjusting for parity, maternal body mass index, gestational age, estimated fetal weight, and amniotic fluid index at time of the version. RESULTS: Over a twelve year period, 1,151 external cephalic version attempts were made of which 31 (2.7%) were on women with a previous cesarean section. Although women with a history of previous cesarean section were more likely to be para ⬎2 (32.3% vs 14.3%), there were no difference in gestational age, estimated fetal weight, and amniotic fluid index. Women with a previous cesarean section had a similar success rate than did women without a previous cesarean section (48.4% vs 52.0%, Adjusted OR: 0.69 (0.19-2.43), p⫽0.56). CONCLUSION: Women with a previous cesarean section who undergo an external cephalic version have similar success rates than do women without a previous cesarean section. Concern about procedural success in women with a previous cesarean section should not be a deterrent to attempting an external cephalic version. 0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.261
0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.259 248 246
HIGHER MAXIMUM DOSES OF OXYTOCIN ARE ASSOCIATED WITH AN UNACCEPTABLY HIGH UTERINE RUPTURE RISK DURING VBAC ALISON CAHILL1, BRIAN WATERMAN2, DAVID STAMILIO1, ANTHONY ODIBO1, JENIFER ALLSWORTH2, BRADLEY EVANOFF1, GEORGE MACONES1, 1Washington University in St. Louis, St. Louis, Missouri, 2 Washington University in St. Louis, Missouri OBJECTIVE: Prior studies have examined the relationship between maximum oxytocin dose and uterine rupture risk in patients attempting vaginal birth after cesarean (VBAC). We sought to more precisely estimate this risk by considering timing and duration of oxytocin dose STUDY DESIGN: A nested case-control study was conducted within a multicenter, retrospective cohort study of women with at least one prior cesarean, comparing cases of uterine rupture to those who did not experience rupture (controls) while attempting VBAC. For this secondary analysis, cases and controls who were exposed to oxytocin were compared using time-to-event analysis to examine the effect of maximum oxytocin dose on the risk of uterine rupture considering therapy duration. Failure was defined as uterine rupture. Time of observation was defined as initiation of maximum dose until event. Cox proportional hazard regression was used to model the effect of maximum oxytocin dose on the risk for uterine rupture, adjusting for relevant confounding effects RESULTS: Within the nested case-control study of 792 patients, 272 were exposed to oxytocin: 62 uterine rupture cases and 210 controls. When compared to a maximum oxytocin dose range of 1-5 milliunits per minute (mu/min), increasing maximum oxytocin dose exposure was associated with a progressive increase in uterine rupture risk CONCLUSION: When the timing and duration of oxytocin dose is considered, higher ranges of maximum oxytocin dose are associated with progressively increasing risk of uterine rupture, with risk magnitude greater than previously estimated by models not considering time. This data supports a maximum oxytocin dose of 20mu/min in VBAC trials to avoid unacceptably high uterine rupture risk. Table 1 Cox proportional hazard model of effect of maximum oxytocin dose on risk of uterine rupture
WHOLE BLOOD HEMOSTASIS IN NORMAL PREGNANCY. LEONIE FLACH1, JORIS LENGLET1, FLEUR BOERSMA1, HERMAN VAN GEIJN1, ANTOINETTE BOLTE1, 1VU University Medical Center, Obstetrics & Gynecology, Amsterdam, Netherlands OBJECTIVE: Our objective is to generate reference values for rotation thromboelastometry during normal pregnancy and in the postpartum period. STUDY DESIGN: Pregnant women were recruited during their first antenatal visit of the obstetric outpatient’s clinic of the VU University Medical Center. Blood samples were taken during regular antenatal visits. Samples were taken 3 times during pregnancy at approximately 12 weeks intervals and 6 weeks postpartum. Data were analysed longitudinally per patient and by trimester: 8 - 20, 20 - 32, and 32 - 42 weeks and postpartum. Women who developed pregnancy complications were excluded from the ‘normal reference value= analysis. Thromboelastometry was performed with ROTEM® Gamma (Pentapharm GMBH, München, Deutschland). Studied are clotting time in seconds (CT), clot formation time in seconds (CFT), maximum clot firmness in millimeters (MCF), clot formation rate in degrees of the largest angle of the curve (CFR) and amplitude in millimeters after 15 and 30 minutes. Testing for intrinsic and extrinsic pathways was performed. RESULTS: A total of 78 patients were tested. Both the tests for intrinsic pathway and the tests for extrinsic pathway show a prothrombotic tendency for all parameters, except the clotting time. CONCLUSION: Prothrombotic state was found to be progressieve during pregnancy and the increase was strongest in the third trimester. By 6 weeks postpartum these changes for the greater part appear te be reversed. Results EXTEG: mean (SD)
8-20 wks 20-32 wks 32-42 wks postpartum
CFT
MCF
CFR
A 15=
A 30=
67,2 (13,0) 75,5 (11,5) 96,9 (7,5) 85,2 (7,0)
74,2 (38,5) 67,8 (2,0) 65,6 (2,0) 73,0 (2,5)
67,5 (10,5) 69,6 (1,0) 71,8 (1,5) 65,5 (3,0)
75,2 (8,0) 76,6 (0,5) 77,1 (0,5) 75,4 (1,0)
64,7 (10,5) 66,7 (1,0) 69,0 (2,0) 69,0 (2,0)
66,4 (11,0) 68,5 (0,0) 70,8 (1,0) 63,8 (2,0)
0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.262
Maximum oxytocin dose (mutran)
Hazard Ratio
95% CI
p
1-5 6-20 21-30 31-40
ref 3.34 3.92 4.57
1.01-10.98 1.06-14.52 1.00-20.85
0.047 0.040 0.050
*Significant covariates in model history of prior vaginal delivery, induction or spontaneous labor, number of prior hysterotoscies. 0002-9378/$ - see front matter doi:10.1016/j.ajog.2007.10.260
S80
CT
American Journal of Obstetrics & Gynecology Supplement to DECEMBER 2007