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Keywords:

  • Cesarean scar defect;
  • Cesarean section;
  • ultrasonography

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Objectives

To determine the ability to correctly identify Cesarean section scars, to estimate the prevalence of defective scars, and to determine the size and location of scar defects by transvaginal ultrasound imaging.

Methods

Two hundred and eighty-seven women underwent transvaginal ultrasound examination 6–9 months after delivery: 108 had undergone one Cesarean section, 43 had had two Cesarean sections, 11 had undergone at least three Cesarean sections, and 125 were primiparae who had delivered vaginally. The ultrasound examiner was blinded to the obstetric history until all scans had been evaluated.

Results

None of the 125 vaginally delivered women had a visible scar in the uterus, whereas all women who had undergone Cesarean section had at least one visible scar. Median myometrial thickness at the level of the isthmus was 11.6 mm in women who had only been delivered vaginally, and 8.3 mm, 6.7 mm and 4.7 mm in women who had undergone one, two and at least three Cesarean sections, respectively (P < 0.001). Scar defects were seen in 61% (66/108), 81% (35/43) and 100% (11/11) of the women who had undergone one, two and at least three Cesarean sections (P = 0.002); at least one defect was classified as large by the ultrasound examiner in 14% (15/108), 23% (10/43) and 45% (5/11) (P = 0.027), and at least one total defect was seen in 6% (7/108), 7% (3/43) and 18% (2/11) (P = 0.336). In women who had undergone one Cesarean section, the median distance between an intact scar and the internal cervical os was 4.6 (range, 0–19) mm, and that between a deficient scar and the internal cervical os was 0 (range, 0–26) mm (P < 0.001).

Conclusions

Cesarean section scars can be detected reliably by ultrasound imaging. Myometrial thickness at the level of the isthmus uteri decreases with the number of Cesarean sections and the frequency of large scar defects increases. Scars with defects are located lower in the uterus than intact scars. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

In past decades the Cesarean section rate has increased markedly1–7. Cesarean section is associated with complications in subsequent pregnancies, such as scar pregnancy with life-threatening bleeding8–10, placenta previa11, 12, placenta accreta, increta or percreta13–15, dehiscence or uterine rupture1, 16–19. It is not known whether defects in Cesarean section scars that are visible at transvaginal ultrasound examination of non-pregnant women are associated with a higher risk of these complications than apparently intact scars20, or whether large defects are associated with a higher risk of complications than small defects, but this might be the case.

The aim of our study was to determine how accurately Cesarean section scars can be detected by transvaginal ultrasonography, to estimate the prevalence of defective scars by using transvaginal ultrasound imaging, and to describe the size, shape and location of scar defects. In addition we wanted to determine which objective measurements of defect size determine whether a defect is perceived subjectively by the ultrasound examiner to be small or large.

METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Subjects

The study protocol was approved by the Ethics Committee of the Medical Faculty of Lund University, Sweden. Informed consent was obtained from all participants, after the nature of the procedures had been fully explained. We aimed at recruiting 100 primipara who had undergone a non-instrumental vaginal delivery, 100 women who had undergone one Cesarean section, and 50 women who had undergone more than one Cesarean section. The names and addresses of women who had delivered at our institution within the preceding 5–8 months and fulfilled our eligibility criteria (at least 18 years old, primipara with uncomplicated vaginal delivery or woman delivered by Cesarean section at least once) were obtained from the labor ward database of our institution. The women so identified were sent a letter of invitation to participate in the study, and those who accepted the invitation were booked for an ultrasound examination. Our exclusion criteria were: previous surgery on the uterus (other than cone biopsy, loop electrosurgical excision procedure, dilatation and curettage, or dilatation and evacuation), pregnancy at the ultrasound examination or no clear information about earlier uterine surgery.

The ultrasound examinations were carried out 6–9 months after the latest delivery. Immediately before the examination, a secretary took a history following a standardized research protocol (parity, medication, contraceptives, breast feeding, day of menstrual cycle, earlier deliveries and gynecological operations) and noted the information on a paper form. The ultrasound examiner was blinded to this information when performing the ultrasound examination as well as when evaluating the images afterwards.

All ultrasound examinations were performed by the first author. The abdomen of the woman to be examined was covered with a towel to hide any abdominal scar, and the women had been instructed to reveal nothing about their obstetric history to the ultrasound examiner. In this way, the ultrasound examiner was blinded to patient history. The examination was carried out transvaginally with the woman in the lithotomy position and with an empty bladder. The uterus was scrutinized for the presence of Cesarean section scars and scar defects. The ultrasound images were evaluated during the ultrasound examination but, in addition, representative images of both longitudinal and transverse sections through the uterus were stored on our digital image storing system, Siemens Syngo® Dynamics, version 5.0 (Siemens Medical Solutions Health Services, Malvern, PA, USA). Any visible defect or indentation in the scar, however small, was classified as a defect. On the basis of subjective evaluation, scar defects were classified as large or not large by the ultrasound examiner. If the ultrasound examiner perceived a scar defect to be large, the woman was informed that the clinical relevance of large defects was unknown, but that we offered a transvaginal ultrasound examination early in a subsequent pregnancy to exclude Cesarean scar pregnancy. Ultrasound images of a scar classified subjectively by the ultrasound examiner as an intact scar, a scar with a small defect and a scar with a large defect are shown in Figure 1.

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Figure 1. Ultrasound images of an intact Cesarean section scar (a), a scar with a small defect (b) and a scar with a large defect (c).

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Immediately after the ultrasound examination, with the obstetric history of the woman still unknown to the examiner, the stored ultrasound images were scrutinized offline and measurements were taken. The following ultrasound features were noted: anteflexion or retroflexion of the uterus, number of visible Cesarean section scars in the anterior wall of the uterus (categorized as clearly visible or difficult to detect), presence of a scar defect (yes or no), shape of a scar defect (triangular, round, oval, or total defect with no remaining myometrium over the defect), and location of the scar defect (right, left, central or other). If more than one scar was seen, the scar lowest in the uterus was called Scar 1, and scars located closer to the fundus uteri than this were numbered 2, 3, etc., with the scar located closest to the fundus uteri being assigned the highest number. The following measurements were taken: the myometrial thickness of the isthmus uteri at the level of the internal cervical os, the distance between an intact scar and the internal cervical os, and the distance between a scar with a defect and the inner cervical os. We defined the level of the internal cervical os as the level at which there is a slight narrowing of the uterus between the corpus and the cervix at the lower boundary of the urinary bladder.

The size of a scar defect was measured both on a longitudinal section through the uterus (length and height of the defect, thickness of the remaining myometrium over the defect, and thickness of the myometrium adjacent to and fundal to the defect; the latter measurement corresponds to measurement ‘m’ in Figure 2c), and on a transverse section through the uterus (width of the defect). If there was a scar defect, the ratio (expressed as a percentage) between the thickness of the remaining myometrium over the scar defect and the thickness of the myometrium adjacent to and fundal to the defect was calculated. The measurement technique is described in Figure 2.

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Figure 2. The distance (d1) between the inner cervical os and an intact scar was measured as shown in (a), i.e. an imaginary (dotted) line was drawn from the internal cervical os (io) to the surface of the anterior cervical lip perpendicular to the cervical canal (this imaginary dotted line represents the thickness of the myometrium in the isthmus), and the distance was measured from the top of this imaginary line to the top of the scar. The distance (d2) between the inner cervical os and a defect scar was measured in the same manner (b). The length (L) and height (h) of the defect, the thickness of the remaining myometrium over the defect (r) and the thickness of the myometrium close to and fundal to the defect (m) were measured as shown in (c). The ratio between r and m (r/m) was calculated. The gray shaded triangular areas in (b) and (c) represent a scar defect.

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All ultrasound examinations were performed using a GE Voluson 730 Expert ultrasound system (General Electric, Zipf, Austria) equipped with a 2.8–10-MHz transvaginal transducer. Not until all ultrasound examinations had been performed and all images evaluated and measurements taken, was information from the obstetric records of the women obtained.

Statistical analysis

Statistical calculations were performed using SPSS version 12.02 (SPSS Inc., Chicago, IL, USA). The statistical significance of differences in categorical data was determined using the chi-square test or Fisher's exact test, as appropriate, and the statistical significance of differences in continuous data using the Mann–Whitney U-test or Kruskal–Wallis test. P < 0.05 was considered statistically significant.

To determine which measurements best predicted whether a scar defect in the lowest scar was subjectively perceived to be large by the ultrasound examiner, receiver–operating characteristics (ROC) curves were drawn separately for women who had undergone one and those who had undergone two Cesarean sections. The area under the ROC curve was calculated with its 95% CI. The measurement was considered to have discriminatory potential if the lower limit of the CI for the area under the ROC curve exceeded 0.5. The measurement with the largest area under the ROC curve was considered to be the best predictor of a defect being perceived to be large by the ultrasound examiner. The ROC curves were also used to determine the best cut-off value mathematically for predicting whether a defect would be perceived to be large by the ultrasound examiner. The best cut-off value mathematically was defined as that corresponding to the point situated furthest from the reference line.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Of 290 women who accepted our invitation to participate in the study and who were examined by ultrasound imaging, three were excluded: one whose history was unclear with regard to possible previous surgery on the uterus, one because of previous myoma enucleation, and one because an early pregnancy was found at the ultrasound examination. Of the 287 women included, 108 had undergone one Cesarean section, 43 had undergone two Cesarean sections, 11 had undergone at least three Cesarean sections, and 125 were primipara who had had an uncomplicated vaginal delivery. Demographic background data are shown in Table 1.

Table 1. Demographic background data
ParameterVaginal delivery (n = 125)One CS (n = 108)Two CS (n = 43)Three or more CS (n = 11)
  1. Values are mean ± SD, n (%) or median (range). CS, Cesarean section.

Age (years)30 ± 4.332 ± 5.233 ± 4636 ± 3.7
Breast feeding88 (70)53 (49)23 (53)6 (55)
Contraception
 None80 (64)69 (64)27 (63)10 (91)
 Intrauterine device19 (15)12 (11)7 (16)0 (0)
 Hormonal contraception26 (21)27 (25)9 (21)1 (9)
Body mass index in first trimester (kg/m2)
 Median (range)23.2 (18.0–35.3)23.5 (17.4–41.0)23.4 (16.5–36.4)25.8 (17.8–40.5)
 Body mass index ≥ 25 kg/m237 (30)41 (38)18 (42)5 (45)
 Body mass index ≥ 30 kg/m27 (6)20 (19)3 (7)2 (18)
Ever miscarried26 (21)13 (12)11 (26)5 (45)
 Miscarried once24 (19)11 (10)8 (19)2 (18)
 Miscarried twice or more2 (2)2 (2)3 (7)3 (27)
Ever underwent pregnancy termination18 (14)19 (18)7 (16)5 (45)
 One termination17 (14)12 (11)5 (12)2 (18)
 Two or more terminations1 (1)7 (6)2 (5)3 (27)
Ever delivered vaginally125 (100)18 (17)4 (9)0 (0)
Number of vaginal deliveries
 One125 (100)15 (14)3 (7)0 (0)
 Two or more0 (0)3 (3)1 (2)0 (0)
Ever underwent an instrumental vaginal delivery0 (0)5 (5)2 (5)0 (0)

All Cesarean sections had been carried out using a transverse lower segment incision. The women who had undergone Cesarean section were examined on average 7 months after the latest Cesarean section (median, 6 months and 27 days; 10th percentile, 5 months and 22 days; 90th percentile, 8 months and 19 days).

The results of the ultrasound examinations in women who had only delivered vaginally and those who had undergone Cesarean section are shown in Table 2. None of the 125 women who had only delivered vaginally had a visible scar in the anterior wall of the uterus at ultrasound examination, whereas all women who had undergone Cesarean section had at least one visible Cesarean section scar. More than two scars were never detected. Two scars were difficult to detect but visible; all the other scars were clearly visible.

Table 2. Ultrasound findings in women who had delivered vaginally or undergone one, two or three or more Cesarean sections (CS)
FindingVaginal delivery (n = 125)One CS (n = 108)Two CS (n = 43)Three or more CS (n = 11)P
  • Values are n (%) unless indicated otherwise.

  • *

    Calculated for women who had undergone one, two or three or more Cesarean sections.

  • Calculated for all four groups of women.

Uterus in anteflexion104 (83)86 (80)33 (77)10 (91)
One visible scar0 (0)108 (100)16 (37)2 (18)
Two visible scars0 (0)0 (0)27 (63)9 (82)
At least one scar with a defect0 (0)66 (61)35 (81)11 (100)0.002*
At least one scar with a large defect (subjective evaluation)0 (0)15 (14)10 (23)5 (45)0.027*
At least one scar with a total defect (subjective evaluation)0 (0)7 (6)3 (7)2 (18)0.336*
Myometrial thickness in the isthmus uteri (mm)     
 Median (range)11.6 (7.9–17.3)8.3 (3.8–15.0)6.7 (3.6–10.7)4.7 (2.4–8.0)< 0.001
 25th, 75th percentiles10.1, 12.97.1, 9.55.3, 7.83.0, 6.0 
Myometrial thickness in the isthmus uteri ≤ 5mm0 (0)2 (2)8 (19)6 (55)< 0.001

The proportion of women with at least one scar with a defect, at least one scar with a large defect and at least one scar with a total defect increased with the number of Cesarean sections, whereas myometrial thickness at the level of the isthmus decreased (Table 2). Scar defects were seen as often in women with a uterus in retroflexion as in those with a uterus in anteflexion (67% (22/33) vs. 70% (90/129), P = 0.731), but large defects (as judged subjectively by the ultrasound examiner) and total defects were seen more often in women with a uterus in retroflexion (30% (10/33) vs. 16% (20/129), P = 0.051; 18% (6/33) vs. 5% (6/129), P = 0.017).

Among the women who had undergone one Cesarean section, the median distance between an intact scar and the internal cervical os was 4.6 (range, 0–19) mm, and that between a deficient scar and the internal cervical os was 0 (range, 0–26) mm (P < 0.001). The median distance between the internal cervical os and a scar with a large and a small defect was similar (0 (range, 0–26) mm vs. 0 (range, 0–18) mm, P = 0.156).

Of a total of 124 scar defects, 110 (89%) were perceived by the ultrasound examiner to be located centrally in the scar and the remaining 14 to be located either to the right (n = 7) or to the left (n = 7) in the scar. Most (103/124, 83%) were perceived to be triangular in shape but some to be round (n = 3), oval (n = 5) or total defects (n = 13; one woman had a total defect in two scars).

The sizes of defects in Cesarean section scars are shown in Table 3. The size of the scar defects (base, height and width), as measured objectively in the lowest and highest scar, was similar in women who had undergone one, two or three or more Cesarean sections, as was the thickness of the remaining myometrium over the defect and the ratio between the remaining myometrium over the defect and the thickness of the myometrium adjacent to the defect. However, the thickness of the myometrium adjacent to a defect in the lowest scar was thickest in women who had undergone only one Cesarean section (Table 3).

Table 3. Size of scar defects in women with one, two or three or more Cesarean sections (CS)
ParameterSize of defect in the lowest scarPSize of defect in the highest scarP
One CS (n = 66)Two CS (n = 35)Three or more CS (n = 11)Two CS (n = 8)Three or more CS (n = 4)
  • Values are median (range) or n (%). Measurements were taken as shown in Figure 2.

  • *

    Ratio between the thickness of the remaining myometrium over the defect and the thickness of the myometrium adjacent to the defect. CS, Cesarean section; NA, not applicable because the number of patients was too small for comparison to be meaningful/possible.

(Length of defect + height of defect)/2 (mm)5.0 (2.0–12.4)4.0 (2.2–10.7)4.3 (2.8–8.9)0.133.8 (3.0–7.3)4.0 (3.0–5.0)0.93
Width of defect (mm)4.1 (1.9–13.7)3.7 (1.6–11.4)4.1 (1.7–7.0)0.563.7 (2.5–9.3)2.8 (2.0–3.0)NA
 Could not be measured4 (6)2 (6)3 (27) 2 (25)2 (50) 
Remaining myometrium over defect (mm)3.2 (0–10.6)3.0 (0–9.5)2.6 (0–7.8)0.582.1 (0–6.9)3.2 (2.3–6.6)0.31
Myometrial thickness adjacent to defect (mm)8.1 (3.8–15.0)6.4 (3.6–12.3)6.9 (3.0–10.8)< 0.0016.6 (4.5–9.1)7.8 (6.0–9.1)0.21
Ratio (%)*39.6 (0–83.3)50.0 (0–83.3)37.6 (0–72.2)0.2132.8 (0–75.8)43.3 (32.9–72.5)0.50
 ≤ 5044 (67)18 (51)6 (55)0.3236 (75)3 (75)NA
 ≤ 2514 (21)6 (17)4 (36)0.3732 (25)0 (0)NA
Thickness of remaining myometrium over defect ≤ 2 mm21 (32)10 (29)5 (45)0.5764 (50)0 (0)NA

The measurements that best discriminated between defects in the lowest scar being perceived to be large or not by the ultrasound examiner were the thickness of the remaining myometrium over the defect and the ratio between the thickness of the remaining myometrium over the defect and the myometrial thickness adjacent to the defect. The ROC curves for these variables are shown in Figure 3 for women who had undergone one Cesarean section and in Figure 4 for women who had undergone two Cesarean sections. In women who had undergone only one Cesarean section the best cut-off mathematically for the thickness of the remaining myometrium over the defect for predicting a large defect was 2.2 mm. This cut-off had a sensitivity of 93% (14/15), a specificity of 86% (44/51) and an accuracy of 88% (58/66). The best cut-off for the ratio between the remaining myometrium over the defect and myometrial thickness adjacent to the defect was 23%, this having a sensitivity of 73% (11/15), a specificity of 94% (48/51) and an accuracy of 88% (58/66).

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Figure 3. Receiver–operating characteristics (ROC) curves for the thickness of the remaining myometrium over a Cesarean scar defect (a) and for the ratio between the remaining myometrium over the defect and the adjacent myometrium (b) with regard to a defect being perceived to be large by the ultrasound examiner. These ROC curves are for women who had undergone one Cesarean section (n = 66). Area under the ROC curve, 0.96 (95% CI, 0.90–1.0) and 0.91 (95% CI, 0.83–0.99) in (a) and (b), respectively.

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Figure 4. Receiver–operating characteristics (ROC) curves for the thickness of the remaining myometrium over a Cesarean scar defect (a) and for the ratio between the remaining myometrium over the defect and the adjacent myometrium (b) with regard to a defect in the lowest scar being perceived to be large by the ultrasound examiner. These ROC curves are for women who had undergone two Cesarean sections (n = 35). Area under the ROC curve, 0.99 (95% CI, 0.97–1.0) and 0.95 (95% CI, 0.88–1.0) in (a) and (b), respectively.

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For women who had undergone two Cesarean sections the best cut-off mathematically for the thickness of the remaining myometrium over the defect for predicting a large defect in the lowest scar was 1.9 mm, this having a sensitivity of 90% (9/10), a specificity of 100% (25/25) and an accuracy of 97% (34/35). The best cut-off for the ratio between the remaining myometrium over the defect and myometrial thickness adjacent to the defect was 31%, this having a sensitivity of 80% (8/10), a specificity of 100% (25/25) and an accuracy of 94% (33/35).

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

This study shows that transvaginal ultrasound imaging is an accurate method for detecting Cesarean section scars. It also shows that defects in Cesarean section scars are common, that the thickness of the myometrium at the level of the isthmus uteri decreases and that the prevalence of scar defects and large scar defects increases with the number of Cesarean sections, that large and total scar defects are more common in uteri in retroflexion than in anteflexion, and that scars with defects are located lower in the uterus than are intact scars. The strength of our study is that it includes a control group of women who had only delivered vaginally, and that the ultrasound examiner was blinded to the obstetric history of the volunteers. A weakness is that neither the reproducibility of our measurements of scar defects nor that of classification of scar defects (as present or absent or as small or large) was determined. To the best of our knowledge, there are no published data on the reproducibility of ultrasound examination of Cesarean section scars in non-pregnant women. However, there is one study comparing interobserver and intraobserver reproducibility of ultrasound measurements of the full lower uterine segment thickness in pregnant women. In that study the reproducibility of measurements taken at transvaginal ultrasound examination was superior to that of measurements taken by transabdominal ultrasound imaging21.

Our study confirms that transvaginal ultrasound imaging can accurately detect Cesarean section scars. These results agree with those of two other studies22, 23. However, Monteagudo et al.24 detected scars at unenhanced ultrasound examination in only one-third (14/44) of women who had undergone Cesarean section. Cesarean section scars seem to be less reliably detectable in pregnant women25. To the best of our knowledge, the number of scars seen at ultrasound imaging was reported in only one study26. Both in our study and in the study cited26, the ultrasound examiner found that the more Cesarean sections the more difficult it was to evaluate the individual scars, and the number of scars seen at ultrasound imaging did not always correspond to the number of Cesarean sections in women who had undergone more than one Cesarean section. This is likely to be explained by fibrotic tissue formed during healing, disturbed anatomy and scar defects interfering with the ability to visualize each individual scar.

The prevalence of scars with a defect was much higher in our study than in others (69% vs. 19%26, 42%23 and 43%22). The discrepancy is most likely to be explained not only by different definitions of defect having been used in the different studies, but also by differences in stage of labor at Cesarean section, indications for Cesarean delivery and operative complications, among others.

To the best of our knowledge, only one published study discriminated between small and large scar defects26, and in only one additional study were the scar defects measured23. Ofili-Yebovi et al.26 defined a ‘severe defect’ as one with ‘loss of more than 50% of the myometrial mantle at the scar level’. Only 10% of the women in their study had a large defect using this definition compared with 42% of the women in our study. The discrepancy might be explained by population differences or by differences in measurement technique, although the measurements seem to have been taken in a similar manner in the two studies. We think it unlikely that differences in timing of the ultrasound examination in relation to the Cesarean section explain the discrepant results. In one study comparing ultrasound findings between women who had undergone Cesarean section 3–12 months, 1–5 years or 5–10 years before the ultrasound examination, the prevalence of a ‘niche’ in the Cesarean section scar was very similar in the three groups22.

Both we and others23, 26 found that the more Cesarean sections the higher the prevalence of deficient scars. This seems natural, because healing conditions are likely to be poorer in tissue where there is already a scar27–30. In our study, the prevalence of large defects as judged subjectively by the ultrasound examiner increased with the number of Cesarean sections. However, using objective measurement criteria to define a large defect we were unable to confirm such a trend. It is possible that subjective evaluation is superior to measurements for classification of defects as large or small, because measurements are unlikely to be precise, and a difference as small as 0.1 mm would classify a defect differently. We also found a clear decrease in myometrial thickness at the level of the isthmus with increasing number of Cesarean sections. Our finding is in agreement with thinning of the lower uterine segment in some pregnant women who have been delivered by Cesarean section31. A lower smooth muscle fiber content with a higher collagen fiber/smooth muscle fiber ratio has been observed in the lower uterine segment of women with Cesarean section scar dehiscence than in women with intact Cesarean section scars or an unscarred uterus27.

It is likely that cervical tissue was incised and included in the suture in cases in which the uterus was opened close to the inner cervical os. This might have affected the healing process negatively and could explain why scars with a defect were located lower in the uterus than were intact scars. Our finding that large scar defects were more common in uteri in retroflexion is in agreement with results reported by Ofili-Yebovi et al.26. They suggested that mechanical tension of the lower uterine segment in a retroflexed uterus might impair blood perfusion and oxygenation of the healing tissues, and that this could affect wound healing negatively. Tissue oxygenation is an important factor for wound healing32.

The clinical importance of visible scar defects, the size of scar defects or the thickness of the myometrium at the level of the isthmus uteri in non-pregnant women is not known. Although one would expect large scar defects to be associated with a higher risk of complications in future pregnancies (e.g. uterine rupture, uterine dehiscence, pathological implantation of placenta, scar pregnancies) than small scar defects or scars that appear intact at ultrasound examination, we do not know if this is the case. The little information available on the importance of myometrial thickness comes from studies of pregnant women who have undergone Cesarean section and had the thickness of their lower uterine segment measured by ultrasound imaging in the second31 or third33, 34 trimester in pregnancy; the risk of scar dehiscence and uterine rupture seems to be increased in women with a thin lower uterine segment in pregnancy, although different cut-offs to indicate an increased risk have been quoted31, 33, 34.

If thin myometrium in the isthmic area after Cesarean section in non-pregnant women proves to be predictive of complications, this measurement might become clinically important. Our results provide the basis for studies on the clinical importance of Cesarean section scar defects and myometrial thinning after Cesarean section.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

This study was supported by two governmental grants: Landstingsfinansierad regional forskning i Region Skåne and ALF-medel.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES