A.V. KAYUMOVA¹, O.A. MELKOZEROVA¹, M.A. MALIKOVA¹, YU.A. SEMENOV², N.V. BASHMAKOVA¹, V.F. NESTEROV¹, G.B. MALGINA¹

 ¹Ural Research Institute of Maternity and Childhood, Yekaterinburg

²Ural State Medical University, Yekaterinburg

Contact details:

Kayumova A.V. — PhD (Medicine), Associate Professor, Deputy Director on Obstetrics and Gynecology

Address: 1 Repin St., 620028 Yekaterinburg, Russian Federation, tel.: +7-982-623-20-47, e-mail: kaum-doc@mail.ru

 The problem of isthmocele formation in the uterine scar after cesarean section is a pressing issue in modern obstetrics, as it is the most common complication of abdominal delivery. Isthmocele has a significant adverse impact on a woman’s life, impairing quality of life, negatively affecting fertility and the results of assisted reproductive technologies. Numerous studies have failed to provide a definitive answer to the etiopathogenesis of isthmocele, pointing only to certain putative risk factors. The main risk factors for isthmocele include the technique used to close the uterine wall, cervical dilation, duration of labor, and associated somatic pathologies. Timely and accurate diagnosis and identification of predictors contributing to the pathology development are among the key challenges in obstetrics in the near future.

Key words: niche, isthmocele, cesarean section, risk factors, scar pregnancy, placenta accrete

REFERENCES

1. Farid M.M., Sepidarkish M., Almukhtar M. et al. Global incidence of surgical site infections following caesarean section: a systematic review and meta-analysis. J. Hosp. Infect, 2023, vol. 139, rr. 82–92. DOI: 10.1016/j.jhin.2023.05.019
2. Angolile C.M., Max B.L., Mushemba J. et al. Global increased cesarean section rates and public health implications: a call to action. Health Sci. Rep, 2023, vol. 6, r. 1274. DOI: 10.1002/hsr2.1274
3. Betran A.P., Ye J., Moller A.B. et al. Trends and projections of caesarean section rates: global and regional estimates. BMJ Glob. Health, 2021, vol. 6, r. 00567. DOI: 10.1136/bmjgh-2021-005671
4. Okladnikov S.M., Nikitina S.Yu., Aleksandrova G.A. et al. Zdravookhraneniye v Rossii. 2025: Stat. sb. Rosstat [Healthcare in Russia. 2025: Stat. collection/Rosstat]. Moscow, 2025. 149 p.
5. Shmakov R.G., Novikova S.V., Il′yashenko E.N. et al. Caesarean section in modern obstetrics: problems and ways to overcome them. Rossiyskiy vestnik akushera-ginekologa, 2025, no. 4, pp. 5–18 (in Russ.). DOI: 10.17116/rosakush2025250415
6. Akadri A.A., Imaralu J.O., Salami O.F. et al. Robson classification of caesarean births: implications for reducing caesarean section rate in a private tertiary hospital in Nigeria. BMC Pregnancy Childbirth, 2023, vol. 23, r. 243. DOI: 10.1186/s12884-023-05557-x
7. Ahmed G.E., Ramy A., Rehab M.A. et al. Effect of cervical changes on the cesarean scar topography after primary cesarean sections: an observational study. BMC Pregn. Childbirth, 2025, vol. 25, rr. 1306. DOI: 10.1186/s12884-025-08396-0
8. Baranovskaya E.I. Caesarean section in modern obstetrics: problems and ways to overcome them. Rossiyskiy vestnik akushera-ginekologa, 2023, no. 5, pp. 32–37 (in Russ.). DOI: 10.17116/rosakush20232305132
9. Maria I.M., Amrita B.M., Charlotte C.M. et al. Postnatal healing of cesarean scar: an ultrasound study. Am. J. Obstet. Gynecol, 2026, vol. 234 (1), rr. 195–209. DOI: 10.1016/j.ajog.2025.09.013
10. Magdalena G., Kinga B., Zofia D. et al. Unveiling the Uterine Niche: The Impact of Isthmocele on Subsequent Pregnancy Outcomes. Biuletyn Głównej Biblioteki Lekarskiej, 2025, vol. 58 (385), rr. 71–94. DOI: 10.2478/bgbl-2025-0018
11. Shahida S., Khawaja F.P., Mohammad S.K. Emerging Manifestations of Cesarean Scar Defect in the Reproductive-Age Group. Cureus, 2025, vol. 17 (11), r. 97287. DOI: 10.7759/cureus.97287
12. Sherif M., Mohamed B.M., Ayman H.S. et al. Cesarean scar defect (CSD): prevalence, risk factors and clinical presentation: a cross-sectional observational study. Middle East Fertil. Soc. J, 2025, vol. 30 (1) DOI: 10.1186/s43043-025-00273-2
13. Abduljawad N., Shujaie A., Raza G. et al. Obstetric paradoxes and didactic equations: the impact of mathematical teaching on childbirth and beyond. Clin. J. Obstet. Gynecol, 2025, vol. 8 (4), rr. 102–107. DOI: 10.29328/journal.cjog.1001198
14. Camran N., Benjamin Z., Kelly B. et al. Outcomes of laparoscopic Cesarean scar defect repair: retrospective and observational study. J. Clin. Med, 2023, vol. 12 (11), r. 3720. DOI: 10.3390/jcm12113720
15. Verberkt C., Jordans I., Van den B. et al. How to perform standardized sonographic examination of uterine niche in non-pregnant women. Ultrasound Obstet. Gynecol, 2022, vol. 60 (33), rr. 420–424. DOI: 10.1002/uog.24953
16. Shunichiro T., Yuri N., Tetsuro H. et al. Prevalence, definition, and etiology of cesarean scar defect and treatment of cesarean scar disorder: A narrative review. Reprod. Med. Biol, 2023, vol. 22, rr. 2532. DOI: 10.1002/rmb2
17. Megan S.N., Brandon B., Ernie S. et al. Incidence and time to niche development following Cesarean delivery: retrospective analysis of a national population-derived database. J Minim. Invasive Gynecol, 2026, vol. 24, rr. 1553–4650. DOI: 10.1016/j.jmig.2026.01.045
18. Ahmed A.T., Sara A.M., Eman Z.E. et al. Diagnostic performance of gynecologic imaging reporting and data system (GI-RADS) in preoperative evaluation of adnexal masses. Medicina (Kaunas), 2025, vol. 61 (4), rr. 679. DOI: 10.3390/medicina61040679
19. Budny-Winska J., Pomorski M. Uterine niche after cesarean section: a review of diagnostic methods. Ginekol. Pol, 2021, vol. 92 (10), rr. 726–730. DOI: 10.5603/GP.a2021.0195
20. Jordans I.P.M., de Leeuw R.A., Stegwee S.I. et al. Sonographic examination of uterine niche in non-pregnant women: a modified Delphi procedure. Ultrasound Obstet. Gynecol, 2019, vol. 53 (1), rr. 107–115. DOI: 10.1002/uog.19049
21. Prateek A., Rajesh K.A., Arushi P. Sonographic assessment of isthmocele and its obstetric complications in subsequent pregnancies: a pictorial review. Indian J. Radiol. Imaging, 2024, vol. 35 (1), rr. 159–168. DOI: 10.1055/s-0044-1788588
22. Ashraf M., Niloofar A., Fatemeh S.K. et al. Impact of obstetric and surgical factors on isthmocele development: insights from a prospective cohort study. Arch. Gynecol. Obstet, 2026, vol. 313 (1), rr. 8. DOI: 10.1007/s00404-025-08297-9
23. Emma B., Filomena G.S., Maria L. et al. Isthmocele diagnosis: The optimal timing for detection. Int. J. Gynaecol Obstet, 2025, vol. 168 (2), rr. 844–846. DOI: 10.1002/ijgo.15892
24. Backer S., Khanna D., Sadr S., Khatibi A. Intra-operative guidelines for the prevention of uterine niche formation in Cesarean sections: a review. Cureus, 2023, vol. 15 (9). DOI: 10.7759/cureus.44521
25. Di Spiezio S.A., Saccone G., McCurdy R. et al. Risk of Cesarean scar defect following single- vs double-layer uterine closure: systematic review and meta-analysis of randomized controlled trials. Ultrasound Obstet. Gynecol, 2017, vol. 50 (5), rr. 578–583. DOI: 10.1002/uog.17401
26. Dominoni M., Torella M., Molitierno R. et al. Single-versus double-layer uterine closure at the time of cesarean delivery and risk of uterine scar niche: a systematic review and meta-analysis of randomized trials. Arch. Gynecol. Obstet, 2025, vol. 312 (4), rr. 1095–1106. DOI: 10.1007/s00404-025-08151-y
27. Zhilkina A.A., Bokieva D.S., Antipova O.V. et al. Cesarean section during labor: ultrasound assessment of postoperative scar healing. Ultrasound Functional Diagnostics, 2025, vol. 31 (2), rr. 40–56. DOI: 10.24835/1607-0771-304
28. Clarel A., Jessica A.M., Jenna S.S. et al. The Impact of uterine incision closure techniques on post-cesarean delivery niche formation and size: sonohysterographic examination of nonpregnant women. J. Ultrasound Med, 2022, vol. 41 (7), rr. 1763–1771. DOI: 10.1002/jum.15859
29. Bujold E., Romero R. Uterine closure after cesarean delivery: surgical technique, biological rationale, and clinical implications. Am. J. Obstet. Gynecol, 2026, vol. 233 (6), rr. 82–102. DOI: 10.1016/j.ajog.2025.10.007
30. Fionnvola A., Karen M., Roisin M.D. et al. Cesarean scar niche: An evolving concern in clinical practice. Review Int. J. Gynaecol. Obstet, 2023, vol. 161 (2), rr. 356–366. DOI: 10.1002/ijgo.14509
31. Ahmed K.K., Ahmed A.Y., Marwa O.E. et al. Incidence of uterine Cesarean scar niche after cesarean delivery and assessment of its risk factors. Medicina (Kaunas), 2025, vol. 61 (9), rr. 1621. DOI: 10.3390/medicina61091621
32. Andrea B., Paolo E., Annalisa I. et al. Investigating the impact of isthmocele and its surgical repair on fertility: results from a systematic review and meta-analysis. Reprod. Biomed. Online, 2025, vol. 50 (6), rr. 104746. DOI: 10.1016/j.rbmo.2024.104746
33. Liu S., Chen L., Zhu G. et al. Analysis of risk factors for cesarean scar diverticulum: a STROBE-compliant case-control study. Medicine (Baltimore), 2021, vol. 100 (17), r. 25757. DOI: 10.1097/MD.0000000000025757
34. Nesterov V.F., Mal′gina G.B., D′yakova M.M., Grishkina A.A. Clinical and morphological variants of incomplete uterine scar after cesarean section. Akusherstvo i ginekologiya, 2025, no. 10, pp. 62–72 (in Russ.). DOI: 10.18565/aig.2025.197
35. Lumbanraja I.L., Aldiansyah D., Halim B. et al. Cesarean scar defect (niche) risk factors: a prospective study on Indonesian women. Curr. Womens Health Rev, 2024, vol. 20 (5), rr. 33–40. DOI: 10.2174/1573404820666230821101739
36. Feldman N., Maymon R., Jauniaux E. et al. Prospective evaluation of the ultrasound signs proposed for the description of uterine niche in nonpregnant women. J. Ultrasound Med, 2022, vol. 41 (4), rr. 917–923. DOI: 10.1002/jum.15776
37. Dogru S., Akkus F., Altınordu Atcı A. et al. Effect of cervical changes on the cesarean scar area and niche formation after preterm and term cesarean sections. J. Ultrasound, 2023, vol. 26 (3), rr. 717–724. DOI: 10.1007/s40477-022-00767-z
38. Sidorova T.A., Martynov S.A. Risk factors and mechanisms of formation of uterine scar defects after cesarean section. Ginekologiya, 2022, no. 1, pp. 11–17 (in Russ.). DOI: 10.26442/20795696.2022.1.201356
39. Baldini G.M., Lot D., Malvasi A. et al. Isthmocele and infertility. J. Clin. Med, 2024, vol. 13 (8), r. 2192. DOI: 10.3390/jcm13082192
40. Radzinskiy V.E., Davydov A.I., Khamoshina M.B. et al. Isthmocele: controversial and unresolved. Voprosy ginekologii, akusherstva i perinatologii, 2025, no. 1, pp. 5–14. DOI: 10.20953/1726-1678-2025-1-5-14
41. Podzolkova N.M., Demidov A.V. et al. Isthmocele: controversial issues of terminology, diagnostics and treatment. Ginekologiya, 2024, no. 2, pp. 119–127 (in Russ.). DOI: 10.26442/20795696.2024.2.202716
42. Masoud S.F., Mahya M., Kiana R. Investigating the risk factors for isthmocele development after cesarean delivery. AJOG Glob. Rep, 2023, vol. 4 (2), rr. 100299. DOI: 10.1016/j.xagr.2023.100299
43. Murji A., Sanders A.P., Monteiro I. et al. Cesarean scar defects and abnormal uterine bleeding: a systematic review and meta-analysis. Fertil. Steril, 2022, vol. 118 (4), pp. 758–766. DOI: 10.1016/j.fertnstert.2022.06.031
44. Saifaldeen A.D., Yasir H.A. et al. A systematic review on Caesarean niche and postmenstrual spotting syndrome: the scar that speaks. Cureus, 2025, vol. 17 (12), rr. 98509. DOI: 10.7759/cureus.98509
45. Min N., Thiel P., McGrattan M. et al. Cesarean scar niche and pelvic pain: a systematic review and meta-analysis. J. Minim. Invasive Gynecol, 2025, vol. 32 (12), rr. 1053–1061. DOI: 10.1016/j.jmig.2025.07.006
46. Ahamed F.M., Solkar S., Stevikova M., Moya B.P. Link between cesarean section scar defect and secondary infertility: Case reports and review. JBRA Assist. Reprod, 2023, vol. 27 (1), rr. 134–141. DOI: 10.5935/1518-0557.20220009
47. Esther R.P., Cristina A.C., Victoria P.E. Cesarean scar pregnancy: Three case reports and literature review. Eur. J. Obstet. Gynecol. Reprod. Biol. X, 2025, vol. 29 (26), rr. 100407. DOI: 10.1016/j.eurox.2025.100407
48. Abdul R.F. Cesarean scar pregnancy: time to initiate universal Screening. Oman Med. J, 2023, vol. 38 (6), r. e564. DOI: 10.5001/omj.2023.131
49. Kayumova A.V., Melkozerova O.A., Bashmakova N.V. Modern instrumental methods for diagnosing pathological placental invasion: a literature review. Akusherstvo i ginekologiya, 2023, no. 6, pp. 5–14 (in Russ.). DOI: 10.18565/aig.2023.57
50. Jordans I.P., Verberkt C., Leeuw R.A. et al. Definition and sonographic reporting system for cesarean scar pregnancy in early pregnancy: modified Delphi method. Ultrasound Obstet. Gynecol, 2022, vol. 59 (4), rr. 437–449. DOI: 10.1002/uog.24815
51. Fu L., Luo Y., Huang J. Cesarean scar pregnancy with expectant management. J. Obstet. Gynaecol, 2022, no. 48, rr. 1683–1690. DOI: 10.1111/jog.15258
52. Lucidi A., Jauniaux E., Hussein A.M. et al. Urological complications in women undergoing Cesarean section for placenta accreta spectrum disorders: systematic review and meta-analysis. Ultrasound Obstet. Gynecol, 2023, vol. 62 (5), rr. 633–643. DOI: 10.1002/uog.26299