Predicting uterine rupture by uterine thickness

A couple weeks ago Virginia from Switzerland left this comment:

I am planning to have a vbac at a hospital in Geneva, Switzerland. In general, they are very supportive of vbacs here.

It is common practice here to measure the uterine scar at 37 weeks using a sonogram. Apparently, if the scar tissue is 3.5mm or higher – it is very unlikely for a rupture. Mine happens to be 2.95mm. The hospital staff tells me I have a 3 – 4% chance of a rupture versus a standard .05% chance of rupture. They warned me that I will be monitored heavily during the birth because of these factors. Do you know much about this theory or know where I can find more information about this?

Typically the rate of rupture quoted for a woman with one prior bikini cut cesarean is about half a percent or 0.5%.  The thickness of the uterine scar/wall and it’s relation to rupture is something I’ve heard discussed quite a bit, but have never personally researched.

My lay opinion?  Intuitively, this makes sense, but the studies we have are not strong enough to prove it.   While it may seem reasonable to say, “The thicker the uterus, the less likely one is to rupture,”  where we do draw the line at what is “thick enough?”  There are several studies that focus on measuring uterine thickness via ultrasound on women with prior cesareans, ten of which are listed below, but none of them are large enough to make any definitive decisions.

When looking at something like uterine rupture that happens about half of a percent of the time, you need to include thousands of test subjects in order to get an accurate assessment of the frequency of the occurrence.  We just don’t have that here.  These are interesting preliminary studies that should be duplicated using thousands of women.  If there is a way to accurately predict which scars will rupture, this is important information to have, but there is currently insufficient evidence available.

No Study total # of women # of women with prior cesarean Notes
1 Rozenberg 1996 642 642 calculates rupture by uterine thickness
2 Cheung 2004 133 53 compares scarred (1.9 ± 1.4 mm), unscarred w/ 1st pg 2.3 ± 1.1 mm; P > .05 , and unscarred w/ 2nd or more pg (3.4 ± 2.2 mm; P < .001)
3 Gotoh 2000 722 348 compares scarred & unscarred
4 Sen 2004 121 71 compares scarred & unscarred
5 Qureshi 1997 43 43 calculates rupture by uterine thickness
6 Michaels 1998 70 58 compares scarred & unscarred
7 Rozenberg 1999 198 198
8 Montanari 1999 61 61 average thickness = 3.82 mm +/- 0.99 mm
9 Cheung 2005 102 102
10 Asakura 2000 186 186

If you, like Virigina, are faced with a minimum uterine thickness standard, request the research your doctor cites and look it up.

If you know of a large study, please leave a comment below with the study citation.

For those who like to skim, I’ve bolded the most interesting parts of the abstracts.

More more information on the subject, check out Sonographic Measurement of the Lower Uterine Segment Thickness: Is it Truly Predictive of Uterine Rupture? by Vincent Y.T. Cheung, MBBS, FRCOG, FRCSC, Department of Obstetrics and Gynaecology, North York General Hospital, University of Toronto, Toronto ON.  It was published in February 2008 and has a great bibliography.

Study #1: Ultrasonographic measurement of lower uterine segment to assess risk of defects of scarred uterus.

Rozenberg P, Goffinet F, Phillippe HJ, Nisand I. Lancet. 1996 Feb 3;347(8997):281-4.  Department of Obstetrics and Gynaecology, Centre Hospitalier Intercommunal, Leon Touhladjian, Poissy, France.

Lower uterine segment thickness Number of cases Number of ruptures
Greater than 4.5 mm 278 0
3.6 – 4.5 mm 177 3 (2%)
2.6 – 3.5 mm 136 14 (10%)
1.6 – 2.5 mm 51 8 (16%)

BACKGROUND: Ultrasonography has been used to examine the scarred uterus in women who have had previous caesarean sections in an attempt to assess the risk of rupture of the scar during subsequent labour. The predictive value of such measurements has not been adequately assessed, however. We aimed to evaluate the usefulness of sonographic measurement of the lower uterine segment before labour in predicting the risk of intrapartum uterine rupture. METHODS: In this prospective observational study, the obstetricians were not told the ultrasonographic findings and did not use them to make decisions about type of delivery. Eligible patients were those with previous caesarean sections booked for delivery at our hospital. 642 patients underwent ultrasound examination at 36-38 weeks’ gestation, and were allocated to four groups according to the thickness of the lower uterine segment. Ultrasonographic findings were compared with those of physical examination at delivery. FINDINGS: The overall frequency of defective scars was 4.0% (15 ruptures, 10 dehiscences). The frequency of defects rose as the thickness of the lower uterine segment decreased: there were no defects among 278 women with measurements greater than 4.5 mm, three (2%) among 177 women with values of 3.6-4.5 mm, 14 (10%) among 136 women with values of 2.6-3.5 mm, and eight (16%) among 51 women with values of 1.6-2.5 mm. With a cut-off value of 3.5 mm, the sensitivity of ultrasonographic measurement was 88.0%, the specificity 73.2%, positive predictive value 11.8%, and negative predictive value 99.3%. INTERPRETATION: Our results show that the risk of a defective scar is directly related to the degree of thinning of the lower uterine segment at around 37 weeks of pregnancy. The high negative predictive value of the method may encourage obstetricians in hospitals where routine repeat elective caesarean is the norm to offer a trial of labour to patients with a thickness value of 3.5 mm or greater.

Study #2: Sonographic Evaluation of the Lower Uterine Segment in Patients With Previous Cesarean Delivery.

Vincent Y. T. Cheung, MBBS, FRCOG, FRCSC, RDMS, Oana C. Constantinescu, MD, RDMS and Birinder S. Ahluwalia, MBBS, RDMS.  J Ultrasound Med 23:1441-1447 • 0278-4297. Department of Obstetrics and Gynecology, North York General Hospital, Toronto, Ontario, Canada (V.Y.T.C.); and BSA Diagnostic Imaging, Toronto, Ontario, Canada (O.C.C., B.S.A.).

Objective. To evaluate the appearance of the lower uterine segment (LUS) in pregnant women with previous cesarean delivery and to compare the LUS thickness with that in women with unscarred uteri. Methods. In a prospective study, sonographic examination was performed on 53 pregnant women with previous cesarean delivery (cesarean group), 40 nulliparas (nullip-control), and 40 women who had 1 or more childbirths with unscarred uteri (multip-control) between 36 and 38 weeks’ gestation to assess the appearance and compare the thickness of the LUS. In the cesarean group, the sonographic findings were correlated with the delivery outcome and the intraoperative LUS appearance. Results. In the cesarean group, 44 patients (83.0%) had a normal-appearing LUS indistinguishable from that of control groups; 2 patients (3.8%) had an LUS defect suggestive of dehiscence; and 7 patients (13.2%) had thickened areas of increased echogenicity with or without myometrial thinning. Although the cesarean group had a thinner LUS (1.9 ± 1.4 mm) when compared with both the nullip-control group (2.3 ± 1.1 mm; P > .05) and the multip-control group (3.4 ± 2.2 mm; P < .001), only the latter difference achieved statistical significance. One of the 2 patients who had a sonographically suspected LUS defect had confirmed uterine dehiscence during surgery. An intraoperatively diagnosed paper-thin LUS, when compared with an LUS of normal thickness, had significantly smaller sonographic LUS measurements (1.1 ± 0.6 versus 2.0 ± 0.8 mm, respectively; P = .004). Conclusions. Prior cesarean delivery is associated with a sonographically thinner LUS when compared with those with prior vaginal delivery. Prenatal sonographic examination is potentially capable of diagnosing a uterine defect and determining the degree of LUS thinning in patients with previous cesarean delivery.

This is the most interesting study because it compares scarred uteri to unscarred uteri that are pregnant for the first time to unscarred uteri that are pregnant for at least the second time.  I think this study is important because when creating a uterine thickness standard, it’s important to understand what is a “safe” thickness.  How thick is an unscarred uterus in its first pregnancy and subsequent pregnancies?  We can then compare this standard to unscarred uteri.  It is fascinating that 83% of the scarred uteri were “indistinguishable” from the unscarred uteri.  Since we are dealing with such small numbers here, 133 women total, it would be irresponsible to create a thickness standard based on this study alone.  If this same study was performed on 10,000 women from each category, that would be a study whose findings would be powerful enough to rightfully influence VBAC policy.

Study #3: Predicting incomplete uterine rupture with vaginal sonography during the late second trimester in women with prior cesarean.

Gotoh H, Masuzaki H, Yoshida A, Yoshimura S, Miyamura T, Ishimaru TObstet Gynecol. 2000 Apr;95(4):596-600. Department of Obstetrics and Gynecology, Nagasaki University School of Medicine, Nagasaki, Japan.

OBJECTIVE: To evaluate the usefulness of serial transvaginal ultrasonographic measurement of the thickness of the lower uterine segment in the late second trimester for predicting the risk of intrapartum incomplete uterine rupture in women with previous cesarean delivery. METHODS: Serial transvaginal ultrasonography with full bladder was performed in 374 women without previous cesarean delivery (control group) and 348 women with previous cesarean delivery (cesarean group) from 19 to 39 weeks’ gestation. The thickness of the lower uterine segment was measured in the longitudinal plane of the cervical canal. RESULTS: The thickness of the lower uterine segment decreased from 6.7 +/- 2.4 mm (mean +/- standard deviation [SD]) at 19 weeks’ gestation to 3.0 +/- 0.7 mm at 39 weeks’ gestation in the control group, but the thickness was more than 2.0 mm throughout this period in each control subject. In the cesarean group, the thickness decreased from 6.8 +/- 2.3 mm at 19 weeks’ to 2.1 +/- 0.7 mm at 39 weeks’ gestation and was significantly thinner than that of the control group after 27 weeks’ gestation (P <.05). Eleven of 12 women (91%) with lower uterine segment less than the mean control – 1 SD in the late second trimester had a very thin lower uterine segment at cesarean delivery with fetal hair being visible through the amniotic membrane, ie, incomplete uterine rupture. In 17 of 23 women (74%) with lower uterine segment less than 2.0 mm in thickness within 1 week (4 +/- 3 days) before repeat cesarean delivery, intrapartum incomplete uterine rupture developed. CONCLUSION: Transvaginal ultrasonography is useful for measurement of the uterine wall after previous cesarean delivery.

Study #4: Ultrasonographic evaluation of lower uterine segment thickness in patients of previous cesarean section

S. Sen, S. Malik and S. Salhan.  International Journal of Gynecology & Obstetrics Volume 87, Issue 3, December 2004, Pages 215-219


To evaluate by ultrasonography, the lower uterine segment thickness of women with a previous cesarean delivery and determine a critical thickness above which safe vaginal delivery is predictable.


A prospective observational study of 71 antenatal women with previous cesarean delivery and 50 controls was carried out. Transabdominal and transvaginal ultrasonography were used in both groups to evaluate lower uterine segment thickness. The obstetric outcome in patients with successful vaginal birth and intraoperative findings in women undergoing cesarean delivery were correlated with lower segment thickness.


The overall vaginal birth after cesarean section (VBAC) was 46.5% and VBAC success rate was 63.5%, the incidence of dehiscence was 2.82%, and there were no uterine ruptures. There was a 96% correlation between transabdominal ultrasonography with magnification and transvaginal ultrasonography. The critical cutoff value for safe lower segment thickness, derived from the receiver operator characteristic curve, was 2.5 mm.


Ultrasonographic evaluation permits better assessment of the risk of scar complication intrapartum, and could allow for safer management of delivery.

Study #5: Ultrasonographic evaluation of lower uterine segment to predict the integrity and quality of cesarean scar during pregnancy: a prospective study.

Qureshi B, Inafuku K, Oshima K, Masamoto H, Kanazawa K.  Tohoku J Exp Med 1997 Sep;183(1):55-65.  Department of Obstetrics and Gynecology, School of Medicine, University of the Ryukyus, Okinawa, Japan.

Table 4: Distribution of delivery mode by lower uterine segment thickness

Lower uterine segment thickness Number of cases Elective C/S Successful TOL Failed TOL
Greater than 2 mm 28 6 (21.4%) 13 (46.4%) 9 (32.1%)
Equal to 2mm 7 5 (42.9%) 2 (28.6%) 2 (28.6%)
Less than 2 mm 8 8 (100%) 0 0
Total 43 17 (39.5%) 15 (34.9%) 11 (25.6%)

They concluded:

2 mm of thickness of the LUS was considered as good healing and less than 2 mm of thickness as poor healing…Twenty two (79%) of 28 women with a well healed scar had trial labor with the result that 46% had a successful vaginal birth without any uterine rupture of dehiscence. Eight women with poor healing all had elective C/S. Seven women with a 2 mm LUS thickness were individually categorized for delivery mode. Two of those women delivered vaginally. The LUS was found to be thin to translucent in these later two groups.

Study #6: Ultrasound diagnosis of defects in the scarred lower uterine segment during pregnancy.

Michaels WH, Thompson HO, Boutt A, Schreiber FR, Michaels SL, Karo J. Obstet Gynecol. 1988 Jan;71(1):112-20.  Department of Obstetrics and Gynecology, Providence Hospital, Southfield, Michigan.

A prospective study was begun using ultrasound to diagnose defects in the lower uterine segment. Seventy patients were examined and delivered by cesarean section, including 58 at risk because of previous cesarean section and 12 nulliparous controls not at risk. Of the at-risk patients, 12 had confirmed defects, for an incidence of 20.7%. All the controls were normal. The false-positive rate for at-risk patients was 7.1%, and the positive and negative predictive values were 92.3 and 100%, respectively. For the diagnosed cases, the sonographic lower uterine segment seemed to form earlier (P less than .01) and was thinner (P less than .01) than that in the negative cases or the controls. Although our study design was observational and did not allow us to test the performance of the lower uterine segment when a defect was found, we discuss the use of a three-stage classification system to assist in identifying sonographically detected defects in a future trial of labor protocol. We conclude that sonographic surveillance is a reliable and practical means of evaluating the lower uterine segment after conception and before labor or delivery.

Study #7: Thickness of the lower uterine segment: its influence in the management of patients with previous cesarean sections.

Rozenberg P, Goffinet F, Philippe HJ, Nisand I.  Eur J Obstet Gynecol Reprod Biol 1999 Nov;87(1):39-45. Department of Gynecology and Obstetrics, Poissy Hospital, University Paris V, France.

OBJECTIVE: To determine how ultrasound measurement of the lower uterine segment affects the decision about delivery for patients with previous cesarean sections (CS) and what are the consequences on cesarean section rates and uterine rupture or dehiscence. DESIGN: Prospective open study. PATIENTS: 198 patients: all women with a previous CS who gave birth in our department during 1995 and 1996 to an infant with a gestational age of at least 36 weeks and who underwent ultrasound measurement of their lower uterine segment (95-96 study group), compared with a similar population from 1989 to 1994 whose measurements were not provided to the treating obstetrician. RESULTS: Among the patients with one previous CS, the vaginal delivery rate did not differ significantly during the two periods (70.3% for the 89-94 study period vs. 67.9% for the 95-96 study period, P=0.53), but the 95-96 study group experienced a significant increase in the rate of elective CS, compensated by a reduction in the rate of emergency CS (6.3% and 23.4%, respectively, for the 89-94 study period vs. 11.9% and 20.1% for the 95-96 study period, P=0.01). There was a very significant increase in the rate of vaginal delivery for the 95-96 study period among patients with two previous CS (26.7% vs. 8.0% for the 89-95 study period, P=0.01). The lower uterine segment was significantly thicker among women with a trial of labor than among those with an elective CS (4.5+/-1.4 mm compared with 3.8 +/- 1.5 mm; P=0.006); and the trial of labor group contained significantly fewer women with a lower uterine segment measurement less than 3.5 mm than did the elective CS group (24.0% compared with 56.6%; P<0.001). Two patients (0.8%) were found to have a defect of the uterine scar, a rate significantly lower than that observed in the early group (3.9%, P=0.03). CONCLUSIONS: Ultrasound measurement of the lower uterine segment can increase the safe use of trial of labor, because it provides an additional element for assessing the risk of uterine rupture. PMID: 10579615, UI: 20044216

I could not find the full article of this study, only the abstract, so I don’t know if the women were permitted  to select their delivery mode or if it was determined by their uterine thickness.

Study #8: [Transvaginal ultrasonic evaluation of the thickness of the section of the uterine wall in previous cesarean sections]. [Article in Italian]

Montanari L, Alfei A, Drovanti A, Lepadatu C, Lorenzi D, Facchini D, Iervasi MT, Sampaolo P.  Minerva Ginecol 1999 Apr;51(4):107-12.  Istituto di Clinica Ostetrica e Ginecologica, Universita degli Studi, IRCCS San Matteo, Pavia.

BACKGROUND: The aim of this study is to evaluate accuracy of transvaginal sonographic examination of the lower uterine segment in pregnant women with previous cesarean section. METHODS: Sixty-one pregnant women between 37 and 40 weeks of gestation, with previous cesarean section underwent transvaginal ultrasonography. Wall thickness of the lower uterine segment, the length of cervix, dilation of the isthmus uteri were measured. On the basis of the surgical findings (in 53 patients) and outcome of the trial of labor (in 8 patients) a Score was assigned to the pregnant women: Score 1 to the women who had good healing or a trial of labor without complications; Score 2 to the women with a thin or discontinued scar and in case of threatened rupture of the uterus in the trial of labor. RESULTS: The mean thickness of the lower uterine segment is 3.82 mm +/- 0.99 mm. The Score 1 group shows a mean thickness of 4.2 mm +/- 2.5 mm, and the Score 2 group a mean thickness of 2.8 mm +/- 1.06 mm. The transvaginal sonographic examination provides a sensitivity and a specificity respectively of 100 and 75%, for a thickness cut-off of 3.5 mm, and a positive and negative predictive values of 60.7% and 100% respectively. CONCLUSIONS: The transvaginal sonographic evaluation of the lower uterine segment improves therefore the obstetrical decision-making regarding the trial of labor in women with previous cesarean section. PMID: 10379144, UI: 99307817

Study #9: Sonographic measurement of the lower uterine segment thickness in women with previous caesarean section.

Cheung VYJ Obstet Gynaecol Can. 2005 Jul;27(7):674-81. Department of Obstetrics and Gynaecology, North York General Hospital, Toronto, ON.

OBJECTIVES: To evaluate the accuracy of prenatal sonography in determining the lower uterine segment (LUS) thickness in women with previous Caesarean section and to assess the usefulness of measuring LUS thickness in predicting the risk of uterine rupture during a trial of vaginal birth. METHODS: Sonographic examination was performed in 102 pregnant women with one or more previous Caesarean sections at between 36 and 38 weeks’ gestation to assess the LUS thickness, which was defined as the shortest distance between the urinary bladder wall-myometrium interface and the myometrium/chorioamniotic membrane-amniotic fluid interface. Of the 102 women examined, 91 (89.2%) had transabdominal sonography only, and 11 (10.8%) had both transabdominal and transvaginal examinations. The sonographic measurements were correlated with the delivery outcome and the intraoperative LUS appearance. RESULTS: The mean sonographic LUS thickness was 1.8 mm, standard deviation (SD) 1.1 mm. An intraoperatively diagnosed paper-thin or dehisced LUS, when compared with an LUS of normal thickness, had a significantly smaller sonographic LUS measurement (0.9 mm, SD 0.5 mm, vs. 2.0 mm, SD 0.8 mm, respectively; P < 0.0001). Two women had uterine dehiscence, both of whom had prenatal LUS thickness of < 1 mm. Thirty-two women (31.4%) had a successful vaginal delivery, with a mean LUS thickness of 1.9 mm, SD 1.5 mm; none had clinical uterine rupture. A sonographic LUS thickness of 1.5 mm had a sensitivity of 88.9%, a specificity of 59.5%, a positive predictive value of 32.0%, and a negative predictive value of 96.2% in predicting a paper-thin or dehisced LUS. CONCLUSIONS: Sonography permits accurate assessment of the LUS thickness in women with previous Caesarean section and therefore can potentially be used to predict the risk of uterine rupture during trial of vaginal birth.

Study #10: Prediction of Uterine Dehiscence by Measuring Lower Uterine Segment Thickness Prior to the Onset of Labor. Evaluation by Transvaginal Ultrasonography.

Hirobumi Asakura, Akihito Nakai, Gen Ishikawa, Shyunji Suzuki and Tsutomu Araki.  Journal of Nippon Medical School.  Vol. 67 (2000) , No. 5 pp352-356. Department of Obstetrics and Gynecology, Nippon Medical School.

Objective: Lower uterine segment thickness was measured by transvaginal ultrasound examination and its correlations with the occurrence of uterine dehiscence and rupture was examined.
Methods: The thickness of the muscular layer of the lower uterine segment was measured in 186 term gravidas with previous uterine scars and its correlation with uterine dehiscence/rupture was investigated.
Results: Uterine dehiscence was found in 9 cases or 4.7%. There were no cases of the uterine rupture. The thickness of the lower uterine segment among the gravidas with dehiscence was significantly less in than those without dehiscence (p< 0.01). The cut-off value for the thickness of the lower uterine segment was 1.6 mm as calculated by the receiver operating characteristic curve. The sensitivity was 77.8%; specificity 88.6%; positive predictive value 25.9%; negative predictive value 98.7%.
Conclusion: Measurement of the lower uterine segment is useful in predicting the absence of dehiscence among gravidas with previous cesarean section. If the thickness of the lower uterine segment is more than 1.6 mm, the possibility of dehiscence during the subsequent trials of labor is very small.

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35 thoughts on “Predicting uterine rupture by uterine thickness

  1. Dr. Dave

    Sorry, but as long as we can get sued for a VBAC complication, I really don’t care what the literature says. Take away the legal risk and Cesarean rates will go down, VBAC rates will go up.

  2. Dr. Loveless

    I disagree with the previous poster. Whenever we make a medical intervention there is risk involved. One of the purposes of scientific study is to evaluate that risk and try to figure out which groups are most at risk. If there were enough power in these studies to identify those who are most at risk for rupture, then we could have real discussions with patients and that would, in turn, help to limit malpractice exposure as the consent would be truly informed.

  3. Pingback: Uterine Thickness as a Predictor of Uterine Rupture « Woman to Woman Childbirth Education

  4. Gigi

    I am not a doctor, but I am a scientist and a woman that has had a c section. I can say that been through major abdominal surgery is no fun. I believe strongly that they should measure the uterine thickness of the LUS and at least allow women that have 4.5 or more to deliver vaginally! while giving the informed option to the others of potential consequences. For a example a 1 hour labour with LUS 3.6 would harly rupture.
    Finally I would say that the amount of c sections whether primary or elective is unethical.

  5. Gigi

    By the way Dr. Dave, have you ever thought that maybe one day you will be sued for an unecessary c section or for complications resulting from it?
    I am planning to sue actually my health provider for that reason, as he has put my future reproductive health at risk by coercing me to unecessary surgery.

  6. Leigha

    I had a VBAC in 2008. When I was planning it, I did extensive research on this measurement (read every study you listed) and corresponded with Dr. Rozenberg in France, author of study #1 on your list. I even had him send me directions for the sonographer at my midwife’s office on how to perform the measurement. I had it done at 37 weeks (at my request – my midwife allowed me to have it done but did not introduce the idea). I had a thickness of 4mm. I knew from the literature that this suggested I had a lower-than-average chance of rupture so I felt very comfortable going through with the VBAC. It worked out great and I would do it all again. I would not have felt comfortable going forward with my VBAC plans if I had had a measurement of under 3mm given the literature. I agree that it would be wonderful to have a larger study done on this.

  7. Amy

    Leigha – would you mind sharing those directions you gave the sonographer for us to have as well please?

  8. Kim

    Did you save the directions on how to perform the measurement? I’d like to have my OB do it as I’m planning a VBAC and I’m 31 weeks.

  9. Jennifer

    I would like to see research on myometrium thickness at the site of a csection scar and the chances of rupture during pregnancy. My scar site measures less than 3mm now and I am considering getting pregnant again, but scared of rupture.

  10. Leigha

    Below are the directions, straight from Dr. Rozenberg; also, I’m emailing Amy the picture of the ultrasound screen that Dr. Rozenberg sent me to show what the screen should look like when the sonographer’s doing the measurement. Hopefully she can update this blog post with the directions and pic.


    Transabdominal examination
    Between 36 and 38 weeks
    Full bladder (visualization of the whole LUS)
    Sagittal sections of the LUS
    Measure of the thinnest zone (upper third of the LUS)
    Calipers at the interface of the bladder and the amniotic fluid-decidua
    LUS in an almost horizontal plane
    3 measurements (smallest value chosen)

    *Note from Leigha: My sonographer used transvaginal, rather than transabdominal, ultrasound because she thought it would provide a clearer picture of the area.

    1. Anna

      I lost my first baby during a c-section and planning a VBAC but I would like to meassure my LUS first. Would any of you be so kind and email me the picture of the ultrasound scan how it shuld look like and any additional instructions? I’m in North Carolina and can’t find any sonographer willing to do this test for me.
      Thank you very much

    2. Anna McCauley

      Dear Leigha
      Would you be so kind and email me the sample picture of the ultrasound scan which you have received from dr Rozenberg?
      I’m planning a vbac and can’t find any sonographer to messure my lower uterine segment.
      I have lost my first child in an emergency c section and I’m due to deliver soon.
      Thank you very much
      Anna McCauley

    3. Carrie

      Hi Leigh,

      My name is Carrie. Could you PLEASE send me an email of the scan you had done. I recently had it done and want to see if my doctor did it correctly. I do not think so since I am 20 weeks and they had me empty my bladder. I am having it done again at 32 weeks and it looks like by your post I should wait until I am 36 weeks. I am also confused because the peri told me that my scar meassured 6.5 all the way across except in one area and he said it was 1.7 however, I do not think they did the test correctly at all. I would so greatful if you would email me the pictures of your scan!!

      Thank you,


  11. Joanna

    Dear All,

    I am posting this because it might help women in this position make an informed decision and not to scare anyone.
    I recently suffered a complete uterine rupture at 41weeks+3days during early labour in hopsital in the UK. I was attempting a VBAC after C section 3.5 years previously. Here it is common practice to encourage VBAC and actively discourage another section.
    Sadly, I lost my daughter Farrah and ended up with an emergency operation to deliver her.
    I never knew about LUS measurements, it was never discussed and despite being a researcher myself, I felt so confident in a VBAC that I never thought to investigate the possibility of rupture.
    As this technique is pretty non invasive I’d say do it – I would have done – but we know there is not enough evidence to suggest that the results will give assurance it may give some. All I can say is consider this, it is much better to have a c section than go through the heartache of losing a beautiful healthy child who you were so close to holding in your arms

  12. amita

    i m a researcher in the initial phases of my work……………….but measuring scar thickness works.if done correctly,so all women planing vbac should get it done,and plan scientific vbac.

  13. Jenifer

    I also would love an email with the screenshot of the proper ultrasound procedure. Could someone who has this screenshot and happens to see this post please send it to me?

  14. Jessie

    I am a 32 year old Australian, very fit and healthy. I delivered my first child 3 1/2 years ago via emergency ceasar. This was a result of foetal distress after being in labour for two weeks at 6 weeks early. At 9cm dialated and two weeks of labour I was given my first pain relief (I was trying to have a natural vaginal birth). Once the Pethadine kicked in, the foetal distress kicked in. I was given no other option but to have an emergency ceasar. I still don’t know if this was the right option. My son was born with a broken arm at birth, by the force of the pull from the doctor trying to get him out as my uterus contracted. I healed very well and so did my son, so I have had no major concerns with my ceasar apart from disappointment at not having the birth I’d planned and a question as to the conduct of the doctor. She was a young and had no other more experienced doctor with her. I believed I shouldn’t question too much all that had happened as I was alive and so was my precious baby.

    It is now 3 and half years later, that I have just discovered via ultrasound investgation that I have a thinning of the uterus on my right hand side where my caesar scar is. My G.P started investigations as I hadn’t fallen pregnant again, despite years of trying. I am in shock and devastation and in the “unknown” as to whether I will be able to have another child, let alone a vaginal birth. I have only seen my G.P at this stage and could be waiting a long period to see my Gyno for an accurate opinion.(Unless you live in a major city in Australia you don’t have a lot of doctors available to you).

    I don’t know the thickness of the thinning site, as my ultrasound doesn’t mention the measurememnt.

    I apologise for the rambling story, but I just had to purge my story, as I sift through internet information trying to find an answer to my dilemma. Can anyone tell me why this happens? And at what point is it downright dangerous to fall pregnant…what thickness will be the absolute minimum. At the end of the day I want to be around for my son, not risking my life and another babies.

    1. Jen Kamel Post author

      Hi Jessie!

      I’m so sorry for all you have been through. I do not know the safe/normal thickness of a unpregnant uterus nor do I know why this might be occurring to you.

      I recommend getting a copy of your medical records and obtaining a second opinion from a VBAC supportive provider. Read Item #3 of this article where I link to several articles regarding finding and interviewing care providers.

      I’m hoping another reader will be able to offer some insight in the meantime.



  15. Jennifer

    As far as I know there is no set standards for thickness. Is this common before having a VBAC where you live? The ultrasound check? In the US it’s not done as I think it’s been proven to mean nothing. I’ve never had my scar checked and have had 3 VBACs, all before my oldest turned 6! My scar has hels up just fine. Can you switch Drs?

  16. mumofar

    I would also like more info on how to get a LUS to test the thickness? I am 18 weeks pregnant and planning VBAC.

    I am also very curious about Study #1. Is there any reason why the rate of rupture was so extraordinarily high in this sample? The rate overall was 4% – more than 8 times the usual rate. Like WTF??

    1. Jen Kamel Post author


      In order to accurately measure uterine rupture (which happens about 0.4% of the time during spontaneous trial of labors after one prior low transverse cesarean) (Landon 2004), a study needs about 5,000 women participating.

      All of these studies have far less women which is why there is not a whole lot of support for measuring uterine thickness in women seeking VBAC nor is it a technique commonly used.

      In the first study (Rozenberg 1996), we had 642 women which means it’s not sensitive enough to provide us with an accurate rate of uterine rupture. Often what happens in smaller studies like this is you either get a really high number, as Rozenberg did, or a really low number.

      I hope that these studies will be replicated using thousands of women. I think the idea is interesting and it might prove to be a good tool. However I think that we currently have insufficient evidence to support the practice of measuring uterine thickness. I personally wouldn’t do it.



  17. Sandy

    I measured uterine thickness at 34 weeks and it was 2.4mm. I am with midwife looking to have VBAC. Does 2.4mm at 34 weeks seem risky for trying out VBAC? I am guessing the thickness will be thiner by the time I go into labour around 40 weeks. Any input as to how you think my risk is would be greatful as I am really torn about this. From the researches, 2.4mm is thought as thin but my midwife doesn’t seem to be sure it is thin. If you had 2.4mm at 34 weeks, what do you think you would do? elective c-section or VBAC?

    1. Jen Kamel Post author


      I don’t put much stock in measuring uterine thickness because the studies do not include enough women to accurately detect uterine rupture. We need about 5,000 women with prior cesareans for that and our largest study here includes 642 – not nearly enough.

      Hopefully these studies will be replicated using more women, but until then, I would not get my uterus measured.



  18. rena


    I just had my LUS measured today and I’m not sure if the measurement I was given is accurate. The technician doing the ultra-sound couldn’t find the scar and when she finally did she said she needed to confirm it with a radiologist first because she wasn’t sure if she was measuring the right thing. Her original measurement was 17mm but the radiologist then confirmed she had indeed found the scar but that her measurement was wrong, its 7mm. What do I do? Should I request a repeat ultra-sound as I’m not sure any of them know what they are talking about?

    1. Jen Kamel Post author


      I don’t think there is sufficient evidence to support measuring uterine/scar thickness as a method to predict uterine rupture.

      I think it’s important to consider what you will do with the information. If they tell you that it’s “to thin,” how will you proceed? Will you ask for the measurement? Will you cross reference it against the studies listed above? Because see, they are not large enough to measure uterine rupture. We need about 5,000 women in a study in order to do that and our largest study above is 642 women.

      I personally think that uterine thickness is used as a way to a) cover the bottoms of practitioners if you do rupture as a way of showing they did all they could to “inform” you and b) to dissuade women from pursuing a VBAC by planting the seeds of doubt.

      Ultimately, you have to decide what makes since to you.



  19. Pingback: Quick Facts on VBACs | Olive Tree Midwifery

  20. dr sunil

    is scar thickness less than 3(1.9mm -2.7mm)is indication of emergency c section at 36 weeks of gestation

  21. Virginia

    I am the original person who posted the question about the scar tissue measurement in Switzerland in 2008. With my scar tissue measuring at 2.95mm, I managed to have a successful VBAC at the hospital in Geneva at 40 plus 3 days. I am about to have my third child in Switzerland and will undergo the same procedure. Since this is common practice in Switzerland, I wonder if some of the universities are keeping track of the data that they are collecting. It would be worth investigating. In addition, there are many people experienced in performing this exam in Switzerland…if someone wants advice, this might be the place to look.


    Iam a professor of radiology.LUS thickess < 2 mm is almost preductive of impending(incomplete ) rupture.If some fluid in soft tissue plane is appreciated in LUS it is very much preductive of rupture and immediate intervention.
    Dr.mithilesh Pratap

  23. dharmendra

    Dear sir i would like to know that my wife uterine scar thickness is 2.8 mm and two cesarion held before 16 month and 7year back and two MTP was held almost three year back,so what should i do ? and what kind of risks cme if she continue with this 28 mm uterine scar thickness.

    1. Jen Kamel Post author

      The evidence on the implications of uterine thickness is not currently strong. You can read more here.



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