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Original article

CLINICAL-MORPHOLOGICAL EVALUATION OFTHE QUALITY OF THE UTERINE SCAR TISSUEAFTER CAESAREAN SECTION

Elitsa Gyokova1, Yordan Popov1, Yoana Ivanova-Yoncheva1, Anton Georgiev1,Miroslava Dimitrova1, Tatyana Betova2, Krasimir Petrov2, Savelina Popovska2,1) Department of Obstetrics and Gynecology, Medical University - Pleven,Bulgaria2) Department of Pathoanatomy, Medical University - Pleven, Bulgaria.

Journal of IMAB - Annual Proceeding (Scientific Papers). 2019 Jan-Mar;25(1)Journal of IMABISSN: 1312-773Xhttps://www.journal-imab-bg.org

ABSTRACTPurpose: Caesarean section (C.S.) is the most

commonly performed operative procedure of the uterus inwomen of reproductive age. Each of these women increasestheir likelihood of complications in subsequentpregnancies. There is an obsolete law in obstetrics: once acesarean, always a cesarean, due to the danger of failure ofthe uterine scar tissue and the greatly increased possibilityof uterine rupture. This necessitates the application ofvarious methods of assessing the sufficiency of the scartissue before planning further deliveries. The most accuratemethods for determining the structure of a tissue arehistological, which by their nature can not be used duringthe pregnancy but they can correlate to clinical ones.

Materials/ Methods: Prospective study of 40pregnant women with previous C.S., divided into groupsaccording to the interval between the operations. Anothersubsequent division of subgroups to the number ofCaesarean sections was made. The morphologicalindicators were compared to a control group of dermal scarfrom the same patients. The results of the clinical methodswere to be compared with the results of the same patientsfrom the morphological studies. We used clinical methodssuch as the history of the previous pregnancies andpuerperal period, history of previous operations and therecovery after them, ultrasound examination and evaluationof the anterior uterine wall preoperatively. Themorphological methods used are: Hematoxylin & eosinstaining (H&E), followed by Masson Trichrome forcollagen; Weigert-Van Gieson staining for elasticity;staining of immunohistochemistry MIB-1 (Ki-67) for cellproliferation.

Results: The study group was presented by patientswith one or more previous C.S. that were divided insubgroups. The shortest inter-delivery interval was 14months, the longest – 19 years. The shorter the periodbetween the C.S.s was, the thinner the myometrium. Casesof abnormal healing have been observed, including:myometrial hyperplasia, adenomyosis, myofiber disarray,elastosis, inflammation, fibroids, keloids. These results canbe compared to clinical data from patients but mainly withthe number of previous C.S. or those with a brief period

https://doi.org/10.5272/jimab.2019251.2433

between them.Conclusions: The results from our research proved

that multiple C.S. is risk factors for larger defects of theuterine scar but not mandatory. The likelihood ofprolonged healing time was higher in cases of more thanone C.S. The dimensions of the surgical incision areassociated with clinical symptoms such as postmenstrualsmears, dysmenorrhoea and chronic pelvic pain.

Keywords: uterine rupture, caesarean section scartissue, vaginal birth after previous caesarean section,uterine dehiscence

INTRODUCTIONCaesarean section (C.S.) is the most commonly

performed operative procedure of the uterus in women ofreproductive age. Each of these women increases theirlikelihood of complications in subsequent pregnancies.There is a continuous discussion about the optimalcaesarean delivery rate and what is the most appropriateone for both maternal and fetal outcome. The increasedrange of C.S. in the last decades is widening newperspectives for complications, and further steps areneeded to reach the optimal percentages. However, in 1916,Edwin Cragin placed an obsolete law in obstetrics that hasbeen executed for a long time: “Once a caesarean, alwaysa caesarean”, due to the danger of failure of the uterine scartissue and the greatly increased possibility of uterinerupture. In the literature is reported that the chance ofuterine rupture in nulliparas during the delivery is 2 per10 000 while it can highly increase with the multiparityand it can reach up to 20-50 per 10 000 in vaginaldeliveries after previous caesarean section [1, 2, 3]. Thisnecessitates the application of various methods of assessingthe sufficiency of the scar tissue before planning furtherdeliveries. The most accurate methods for determining thestructure of tissue are histological, which by their naturecannot be used during the pregnancy. These methodscorrelate with some clinical ones that we tried to prove.

Several big obstetrical organizations agreed onvaginal birth after prior caesarean section to be first choiceoption as clinically safe for women with one previous C.S.

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– not only for the clinical benefits and the decreasedpossible complications but also for the economic and socialfactors caused by the earlier recovery [4, 5, 6, 7, 8, 9]

It is known and confirmed by many researchers thatfactors such as short interval less than 12 months betweenthe deliveries, macrosomia of the baby, oligohydramnion,post-term pregnancies, low pelvic score and thinmyometrial thickness on ultrasound examination areincreasing the rate of uterine rupture during VBAC [10, 11,12, 13, 14, 15, 16]. Another retrospective study [17]examined specifically patients with short inter-deliveryinterval and concluded that it is not increasing significantlythe incidence of uterine rupture.

Lower uterine segment (LUS) thickness measurementin prenatal women with a history of past caesarian sectionscould be used as a tool to predict the occurrence of auterine defect (dehiscence or rupture of the uterine scar) inwomen undergoing VBAC. This was suggested in a meta-analytical study [18], and it further added, that theminimum thickness lying above the amniotic cavity at thelevel of the uterine dehiscence cut-off range of between2.1-4.0 mm gives a strong negative predictive value for auterine defect to occur during VBAC, whereas a myometrialthickness cut-off range of between 06-2.0 mm provides apositive predictive value for uterine defects to occur.However, according to the study, it wasn’t possible todefine a realistic cut-off thickness which could beimplemented in clinical practice.

MATERIAL/METHODSCross sectional study was designed to examine

women with prior Caesarean sections. For eight months,samples of 40 women hospitalized in Clinic of Obstetricsand Gynecology at the University Hospital – Pleven,Bulgaria were examined. Patients’ demographic data werecollected by a questionnaire after informed consent. Thestudy was a part of a scientific project funded by theMedical University – Pleven, Bulgaria. The study protocolwas approved by the Ethics Committee of MedicalUniversity – Pleven. The data were statistically analyzedusing the X2 test and P < 0.05 was accepted as the level ofsignificance.

Clinical methods were used such as the history ofthe previous pregnancies and puerperal period, history ofprevious operations and the recovery after them, ultrasoundexamination and evaluation of the anterior uterine wallpreoperatively. All the patients had been examined withultrasound antenatally to measure the thickness of the loweruterine segment (scar dehiscence or scar rupture). Duringthe operation for delivering the baby, a biopsy materialfrom the uterine scar was collected to be evaluatedhistopathologically. The morphological methods used are:Hematoxylin & eosin staining (H&E); Masson Trichromefor evaluating the amount of collagen; Weigert-Van Giesonstaining for elasticity; staining of immunohistochemistryMIB-1 (Ki-67) for cell proliferation. The morphologicalindicators were compared to a control group of dermal scarsfrom the same patients.

RESULTSThe study group was presented by patients with one

or more previous C.S. They were divided as following:Group A – 23 (57.5 %) patients with one C.S. and subgroupA1 – less than 2 years ago (6 patients – 15 %), subgroupA2 – more than 2 years (17 patients – 42.5 %); Group B –with more than one C.S. (17 patients – 42.5 %). The womenwere at the age between 16 and 40 years, mean age28.04±sd 10.958. Twenty-three (57.5%) of the women livein villages, and the other seventeen (42.5%) live in cities.According to ethnic group, the study population included:Bulgarians – 19 (47.5%) and minority – 21 (45%). Maritalstatus showed that only 5 (12.50%) were married. There wasno statistically significant difference between ethnicity andthe healing processes in the examined group. Also, there isno statistically significant difference between maritalstatus, living location and the uterine scar recovery.

Group A Group BOne previous More than one

C.S. C.S.Total number

of patients 23 17in the group

Bulgarians 13 6

Minority 4 17

Married 4 1

The shortest inter-delivery interval was 14 months,the longest – 19 years. The ultrasound measurement resultsof the front uterine wall were between 1,73 mm and 3,79mm. The shorter the period between the C.S.s was, thethinner the myometrium.

Cases of abnormal healing have been observed,including: myometrial hyperplasia, myometrialhypertrophy (fig. 1), adenomyosis (fig. 2), myofiber disarray(fig. 3), fibrosis (fig. 4), inflammation (fig. 5), fibroids,keloids. These results can be compared to clinical data frompatients but mainly with the number of previous C.S. orthose with less than 2 years between them.

Fig. 1. Scar with myometrial hypertrophy and fibrosis

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Fig. 2. Adenomyosis with haemorrhages Fig. 5. Scar tissue with signs of inflammation

Fig. 3. Myofiber disarray with Masson Trichromestaining

Fig. 4. Weigert-Van Gieson staining for elasticity

DISCUSSIONOur results indicate that there is a high frequency

(60%) of low healing in patients with prior C.S. less thantwo years from women who experienced longer interval.Routine screening of pregnant women for the dimensionof the uterine scar is currently not practiced in our region.However, the dimensions of the surgical incision areassociated with clinical symptoms such as postmenstrualsmears, dysmenorrhoea and chronic pelvic pain. Theincidence of tearing in the evaluated group was higher inpatients with a short interval between births (below 24months), a caesarean infection, two or more caesareansections.

In our study women from group, A1 was associatedto be more commonly with insufficiency of the uterine scarwith histologically “young” cells proliferation (fig. 6).Infections were found regardless the ethnicity, butsignificantly predominantly observed in the group of lowsocial status patients.

Fig. 6. Uterine scar with histologically “young” cellsproliferation

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Brown SS, Dean TM, Frederiksen M,Rowland Hogue CJ, et al. NIH consen-sus development conference draftstatement on vaginal birth aftercesarean: new insights. NIH ConsensState Sci Statements. 2010 Mar10;27(3):1-42. [PubMed]

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11. Dekker GA, Chan A, Luke CG,Priest K, Riley M, Halliday J, et al.Risk of uterine rupture in Australianwomen attempting vaginal birth afterone prior caesarean section: a retro-spective population-based cohortstudy. BJOG. 2010 Oct;117(11):1358-65. [PubMed] [Crossref]

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Patients who experienced a smooth puerperal periodwith the prior deliveries and had long (two years at least)inter-delivery interval, were evaluated as clinicallyqualitative scar tissues (fig. 7). Their results of theultrasound measurements were between 2,3 and 3,79 mm.Those patients are concluded to be safe for VBAC.

Fig. 7. Qualitative scar tissues with Weigert-VanGieson staining

disarray and inflammation signs.Women with haemoglobin levels less than 110 g/l

during the re-elective C.S. were diagnosed with pregnancy-related anaemia. The ultrasound measurements of thepatients with anaemia showed thickness of the uterine scarless than 2.5 mm. Histologically the tissue material fromthese patients showed low cells proliferation.

CONCLUSIONThe results from our research proved that multiple

C.S. is risk factors for larger defects of the uterine scar butnot mandatory. The likelihood of prolonged healing timewas higher in cases of more than one C.S. Ultrasoundmeasurement of prior uterine scar is a useful method forinvestigating the possible complications of spontaneousvaginal birth and for detecting the patients for Re-C.S., butwe recommend its wider use at the time a pregnancy is inthe third trimester to enable individual risk assessment andprevention. Not only the clinical history but also the livequality standards such as well-balanced diet, clean homeand regular daily activities are decreasing the rate ofunwanted complications and healing abnormalities.However, further researches are needed to recognize all therisk factors and the precise incidence of complications.

ACKNOWLEDGEMENTSThis research was funded by Medical University –

Pleven through research project No.6/2017.There were two cases of patients with a history of

fever during the puerperal period after the previous C.S. –the scars of these patients were found to be with myofiber

J of IMAB. 2019 Jan-Mar;25(1) https://www.journal-imab-bg.org 2437

Address for correspondence:Elitsa GyokovaDepartment of Obstetrics and Gynecology, Faculty of Medicine, Medical Uni-versity - Pleven1, Kliment Ohridski Str., 5800 Pleven, Bulgaria.E-mail: egyokova@yahoo.com

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17. Kessous R, Sheiner E. Is therean association between short intervalfrom previous cesarean section and ad-verse obstetric and perinatal outcome?J Matern Fetal Neonatal Med. 2013

Jul;26(10):1003-6. [PubMed][Crossref]

18. Kok N, Wiersma IC, OpmeerBC, de Graaf IM, Mol BW, Pajkrt E.Sonographic measurement of loweruterine segment thickness to predictuterine rupture during a trial of laborin women with previous Cesarean sec-tion: a metaanalysis. UltrasoundObstet Gynecol. 2013 Aug;42(2):132-9. [PubMed] [Crossref]

Please cite this article as: Gyokova E, PopovY, Ivanova-Yoncheva Y, Georgiev A, Dimitrova M, Betova T, Petrov K,Popovska S. Clinical-morphological evaluation of the quality of the uterine scar tissue after caesarean section. J ofIMAB. 2019 Jan-Mar;25(1):2433-2437. DOI: https://doi.org/10.5272/jimab.2019251.2433

Received: 27/10/2018; Published online: 21/03/2019