Research on Signs of Uterine Rupture

This page includes summaries of some studies which looked at the signs of uterine rupture. All the abstracts are available on Medline via the Grateful Med site.

The effect of uterine rupture on fetal heart rate patterns.

J Nurse Midwifery 1999 Jan-Feb;44(1):40-6

Menihan CA

Women and Infants Hospital, Providence, RI, USA.

The high success rate of vaginal birth after cesarean section (VBAC) and its low association with complications has led to VBACs being attempted at all types of facilities, including birth centers. It must be kept in mind that unpredictable uterine rupture can occur and that uterine rupture necessitates emergency intervention. The only reported predictable feature of fetal heart rate patterns in response to uterine rupture is the sudden onset of fetal bradycardia. Fetal patterns are presented to illustrate this finding.

In this study, we are told that "Fetal heart abnormalities were observed in all cases in which the uterus ruptured during labor", but unfortunately the abstract doesn't tell us how long these abnormalities went on for. Note the low incidence of rupture - 0.012% overall - and the association with use of oxytocin or prostaglandins.

Case series of uterine rupture and subsequent pregnancy outcome

AUTHORS: Al Sakka M; Dauleh W; Al Hassani S
AUTHOR AFFILIATION: Department of Obstetrics and Gynaecology, Women's Hospital, Hamad Medical Corporation, Doha, Qatar.
SOURCE: Int J Fertil Womens Med 1999 Nov-Dec;44(6):297-300
CITATION IDS: PMID: 10617251 UI: 20083541

ABSTRACT: OBJECTIVE: TO review the incidence of ruptured uterus at Women's Hospital, Hamad Medical Corporation (HMC), highlight the management approach of suture repair in relation to maintaining the patient's future fertility, and study subsequent pregnancy outcome and the risk of recurrent uterine rupture.

METHODS: Case notes were reviewed for every patient with a ruptured uterus at the Women's Hospital in Doha for a period of 15 years, from 1 January 1983 to 31 December 1997.
RESULTS: There were 17 cases of ruptured uterus. The incidence of ruptured uterus was calculated to be 0.012%; eight (47%) of these occurred in patients with previous cesarean scars, while nine cases (52.9%) were grand multiparas (5 or more). In nine cases (52.9%), uterine rupture was associated with oxytocin use, and four patients (23.5%) were associated with prostaglandin E2 (PGE2) use. The ruptures occurred in the posterior uterine wall in one patient, the scar of a classical cesarean section in another, and in the lower segment in the remainder. Fetal heart abnormalities were observed in all cases in which the uterus ruptured during labor. Abdominal hysterectomy was performed in eight cases (47%). The remaining nine patients had suture repair, two with sterilization, and the other seven without sterilization. Six of these subsequently became pregnant, for a total of ten babies, all delivered by cesarean section.

CONCLUSION: Even though rupture of the uterus was rare in our study, its occurrence should be suspected when there are sudden fetal heart abnormalities during labor or unexpected antepartum or postpartum hemorrhage. Suture repair should be considered whenever possible to maintain the patient's future fertility.

Uterine rupture in women attempting a vaginal birth following prior cesarean birth.

Menihan CA

J Perinatol 1998 Nov-Dec;18(6 Pt 1):440-3

Department of OB/GYN, Women and Infants Hospital, Brown University School of Medicine, Providence, RI 02905, USA.

OBJECTIVE: To determine (1) if there are any common features to fetal heart rates (FHR) and uterine activity patterns before uterine rupture, (2) if neonatal outcomes as reflected by cord blood gases are associated with the length of fetal bradycardia, and (3) if there is an increase in maternal and/or neonatal length of stay in women who experience uterine rupture during labor as compared with women following repeat cesarean section.

METHODS: Maternal and fetal records of 11 women identified by the ICD-9 code as having had a uterine rupture between 1990 and 1995 were retrospectively reviewed.

RESULTS: No one common feature in FHR patterns or uterine activity existed before uterine rupture other than bradycardia, although variable and/or late decelerations commonly preceded the bradycardia. Of the neonates, 91% had cord blood pH of < 7.0 and 45% had base excess greater than 15 meq/l. Of those fetuses experiencing bradycardia, 55% had placental abruption. Maternal length of stay 5 days or greater occurred in 36% of those with uterine rupture. Seventy-three percent of the neonates required admission to the Neonatal Intensive Care Unit (NICU). Despite acidemia as shown by cord pH, none of the neonates experienced seizures or multiorgan dysfunction.

CONCLUSION: There is no one specific FHR or uterine activity pattern that indicates the onset of a uterine rupture, although variable and/or late decelerations occur before the onset of an FHR bradycardia. In the present study, neonatal admissions to the NICU were increased and pH values were below 7.0 in 91% when uterine rupture occurred. A decrease or cessation of uterine tone was not observed. Maternal length of stay was slightly increased following uterine rupture.

Risk of uterine rupture after the partographic 'alert' line is crossed--an additional dimension in the quest towards safe motherhood in labour following caesarean section.

JPMA J Pak Med Assoc 1996 Jun;46(6):120-2

Khan KS, Rizvi A, Rizvi JH

Department of Obstetrics and Gynaecology, Aga Khan University Medical Centre, Karachi.

To determine if prolonged active phase of labour is associated with increased risk of uterine scar rupture in labour following previous lower segment caesarean section, a retrospective cohort study (1988-91) was done to analyse active phase partographs of 236 patients undergoing trial of labour following caesarean section, 7 (3%) of whom had scar rupture.

After onset of active phase (3 cm cervical dilatation), a 1 cm/h line was used to indicate "alert". A zonal partogram was developed by dividing the active phase partographs into 5 time zones: A (area to the left of "alert" line), B (0-1 h after "alert" line), C (1-2 h after "alert" line), D (2-3 h after "alert" line) and EF (> 3 h after "alert" line). The relative risk of uterine scar rupture was calculated for different partographic time zones.

The relative risk of uterine scar rupture was 10.5 (95% confidence interval 1.3-85.5, p = 0.01) at 1 hour after crossing the "alert" line; 8.0 (95% confidence interval 1.6-40.3, p = 0.009) at 2 hours after crossing the "alert" line; and 7.0 (95% confidence interval 1.6-29, p = 0.02) at 3 hours after crossing the "alert" line.

In women undergoing trial of labour following caesarean section, prolonged active phase of labour is associated with increased risk of uterine rupture. A zonal partogram may be helpful in assessing this risk in actively labouring women who cross the partographic "alert" line.

The partograph in the management of labor following cesarean section.

Int J Gynaecol Obstet 1995 Aug;50(2):151-7

Khan KS, Rizvi A

Department of Obstetrics and Gynecology, Aga Khan University Medical Center, Karachi, Pakistan.

OBJECTIVE: To determine whether graphic labor record (partogram) can be used to predict the risk of uterine scar rupture in labor following lower segment cesarean section.

METHODS: Between 1988 and 1991, 236 women had a trial of labor following cesarean section. After the onset of the active phase (3 cm cervical dilatation), a 1 cm/h line was used to indicate an alert line on the partogram. All the active phase partograms were divided into five time zones: A (area to the left of the alert line), B (0-1 h after the alert line), C (1-2 h after the alert line), D (2-3 h after the alert line), and E and F (> 3 h after the alert line). For the action line, different lag times after the alert line were defined according to the time zones. Sensitivity, specificity, cesarean section rates and rupture rates were calculated for the different lag times after the alert line, and a receiver-operating characteristic curve was constructed.

RESULTS: Fifty-five (23.3%) trials of labor ended in a repeat emergency cesarean. There were seven (2.9%) cases of scar rupture. Of the 181 vaginal deliveries, 151 (83%) occurred within 2 h after the progress of labor had crossed the alert line (zones A-C). Five out of seven cases of scar rupture occurred more than 2 h after the alert line had been crossed (zones D-F). The 2- and 3-h lag time after the alert line had a sensitivity of 71% and 43%, respectively, and a specificity of 78% and 96%, respectively, in predicting uterine scar rupture. If cesarean sections were performed at 2 or 3 h after crossing the alert line, the projected cesarean rates would have been 36% and 27%, respectively. The scar rupture rates would in turn be 0.8% and 1.6%, respectively.

CONCLUSION: In women undergoing a trial of labor following cesarean section, the partographic zone 2-3 h after the alert line represents a time of high risk of scar rupture. An action line in this time zone would probably help reduce the rupture rate without an unacceptable increase in the rate of cesarean section.

Uterine rupture during trial of labor after previous cesarean section.

Am J Obstet Gynecol 1991 Oct;165(4 Pt 1):996-1001

Farmer RM, Kirschbaum T, Potter D, Strong TH, Medearis AL

Department of Obstetrics and Gynecology, University of Southern California, Los Angeles 90033.

This study was undertaken to determine the incidence and associations of uterine rupture and dehiscence with an attempted vaginal birth after cesarean section. The charts from 137 patients who had uterine scar separation after a previous cesarean section from 1983 to 1989 were examined. Approximately 9.3% of the 119,395 women who were delivered in that interval had a prior cesarean section. Of those, 68.8% underwent a trial of labor with a 79.2% success rate.

The uterine rupture rate in this latter group was 0.8%, while an additional 0.7% had a bloodless dehiscence. Bleeding and pain were unlikely findings with a uterine scar separation (3.4% and 7.6%, respectively). The most common manifestation of a scar separation was a prolonged fetal heart rate deceleration leading to operative intervention (70.3%).

We conclude that, although the incidence of uterine rupture was low, the event is most often seen as an acute emergency. Prevention should be directed toward timely diagnosis and prompt management of labor dystocias. Staff and facilities for safe management of a uterine scar separation are a requisite for the conduct of a vaginal birth after previous cesarean section.

Symptoms and signs with scar rupture -value of uterine activity measurements.

This study looked at whether monitoring contractions, particularly by intrauterine pressure measurements, helped to predict cases of scar rupture.

Aust N Z J Obstet Gynaecol 1992 Aug;32(3):208-12

Arulkumaran S, Chua S, Ratnam SS

Department of Obstetrics and Gynaecology, National University Hospital, Singapore.

To evaluate the symptoms and signs of scar rupture with special reference to intrauterine pressure measurement a retrospective analysis of labour records of those women who had trial of labour with a previous Caesarean scar in the National University Hospital over a period of 6 years (1985-1990) was carried out.

Of the 1,018 women with previous Caesarean scar (4.2% of our pregnant population at term) 722 (70.9%) had trial of labour; 70% delivered vaginally.

There were 4 (0.55%) incomplete and 5 (0.69%) complete scar ruptures. All 9 women had an oxytocin infusion; 3 were diagnosed postdelivery (all 3 had complete ruptures); 3 of the 6 who had rupture prior to delivery had sudden reduction in uterine activity, 1 had scar pain and prolonged bradycardia and 2 had no symptoms or signs.

Continuous cardiotocography with intrauterine pressure measurements may help to identify scar rupture early and may be of value especially in those who have an oxytocin infusion.

Rupture of the scarred uterus.

Obstet Gynecol Clin North Am 1988 Dec;15(4):737-44

Clark SL

Utah Valley Regional Perinatal Center, Provo.

Although theoretically important, the bulk of obstetric literature indicates that scar separation following a lower transverse uterine incision is not a significant problem in clinical obstetrics. The need for emergency intervention for such scar separation is not increased over that in any laboring patient for a number of other causes.

Ideally, the capability of emergency intervention should be available for any laboring patient. In reality, however, such a situation will not commonly be present in all hospitals in the United States. The absence of in-house anesthesia coverage does not appear to be a valid reason to exclude the carefully informed patient from a trial of labor following a previous low transverse uterine incision.

Not only is scar separation infrequent, but maternal and perinatal morbidity should be negligible when such scar separation does occur. The use of oxytocin and epidural anesthesia appears to be appropriate. The latter does not mask signs or symptoms of scar separation.

Because most scar separation will be heralded by the appearance of variable decelerations, extremely careful fetal heart-rate monitoring is mandatory for any patient laboring with a previous uterine incision.


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