Association between Myometrial Thickness and Assisted Reproductive Technologies Outcomes: A Prospective Cohort Study

Document Type : Original Article


1 Department of Endocrinology and Female Infertility, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran

2 Asali Charity Hospital, Lorestan University of Medical Science, Lorestan , Iran

3 Department of Biostatistics and Epidemiology, School of Health, Guilan University of Medical Sciences, Rasht, Iran

4 Department of Reproductive Imaging, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran


Background: Myometrial thickness has been expected to be a prognosticator for lower uterine segment function. An
abnormal function of the uterine muscle layer can cause common and important reproductive problems. This study
aimed to evaluate the relationship between the baseline myometrial thickness and assisted reproductive technologies
(ART) outcomes.
Materials and Methods: In this prospective cohort study, 453 infertile women undergoing ART cycles without any
obvious uterine pathology, participated in this prospective cohort study from February 2013 to May 2015. In order to
measure the myometrial thickness in the anterior and posterior of the uterine, trans-vaginal ultrasounds were conducted on
days 2-4 of the cycle (menstrual phase) preceding ovarian stimulation and the day of human chorionic gonadotropin
(hCG) injection. We defined three groups based on the baseline myometrial thickness in the anterior and posterior, including
(A) <25 mm, (B) 25-29.9 mm and (C) ≥30 mm. Ovarian stimulation, oocyte retrieval and luteal phase support were
performed in accordance with the standard long protocol. Two weeks after embryo transfer, the patients underwent a
pregnancy test by checking their serum β-hCG levels. The primary outcome measure was the clinical pregnancy rate. Secondary
outcome measures were implantation rate, abortion rate and live birth rate.
Results: The clinical pregnancy (P=0.013) and implantation (P=0.003) rates were significantly lower in group A than
in two other groups. Although the live birth rate was lower in group A than two other groups, this decrease was not statistically
significant (P=0.058).
Conclusion: The findings may be a way for clinicians to draw focus on providing therapeutic strategies and a specific
supportive care for women with a baseline myometrial thickness <25 mm in order to improve the reproductive outcome
of in vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI).


Main Subjects

  1. Aguilar HN, Mitchell BF. Physiological pathways and molecular mechanisms regulating uterine contractility. Hum Reprod Update. 2010; 16(6): 725-744.
  2. Kagami K, Ono M, Iizuka T, Matsumoto T, Hosono T, Sekizuka- Kagami N, et al. A novel third mesh-like myometrial layer connects the longitudinal and circular muscle fibers -A potential stratum to coordinate uterine contractions. Sci Rep. 2020; 10(1): 8274.
  3. Gürsoy Erzincan S, Sayin NC, Korkmaz S, Sutcu H, Inan C, Uzun Cilingir I, et al. Can myometrial thickness/cervical length ratio predict preterm delivery in singleton pregnancies with threatened preterm labor? A prospective study. Arch Gynecol Obstet. 2019; 299(5): 1275-1282.
  4. AtarJavdan L, Khazaeipour Z, Shahbazi F. Correlation of myome­trial thickness and the latency interval of women with preterm pre­mature rupture of the membranes. Arch Gynecol Obstet. 2011; 284(6): 1339-1343.
  5. Malik M, Roh M, England SK. Uterine contractions in rodent mod­els and humans. Acta Physiol (Oxf). 2021; 231(4): e13607.
  6. Chen C, Zhu S, Bai L, Sui M, Chen D. The role of formyl peptide re­ceptor 1 in uterine contraction during parturition. Front Pharmacol. 2021; 12: 696697.
  7. Deyer T, Ashton-Miller JA, Van Baren PM, Pearlman MD. Myome­trial contractile strain at uteroplacental separation during parturi­tion. Am J Obstet Gynecol. 2000; 183(1): 156-159.
  8. Tanos V, Lingwood L, Balami S. The importance of the junction­al zone of the endometrium in human reproduction. Hum Fertil (Camb). 2022; 25(1): 4-12.
  9. Lesny P, Killick SR. The junctional zone of the uterus and its con­tractions. BJOG. 2004; 111(11): 1182-1189.
  10. Chizen DR, Pierson RA. Transvaginal ultrasonography and female infertility. The global library of women’s medicine. 2010. Avail­able from:­vaginal%20ultrasonography%20and%20female%20infertility/ item/325# (22 May 2016).
  11. Kolade-Yunusa HO, Abdullahi HI, Salaam AJ. Evaluation of infertile women using transvaginal ultrasound in a tertiary health facility. Jos J Med. 2019; 13(2): 12-20.
  12. Hamdi K, Bastani P, Saheb-Madarek EO, Hosseini H. Prediction of latency interval in preterm premature rupture of membranes using sonographic myometrial thickness. Pak J Biol Sci. 2010; 13(17): 841-846.
  13. Lesny P, Killick SR, Tetlow RL, Manton DJ, Robinson J, Maguiness SD. Ultrasound evaluation of the uterine zonal anatomy during in-vitro fertilization and embryo transfer. Hum Reprod. 1999; 14(6): 1593-1598.
  14. Youm HS, Choi YS, Han HD. In vitro fertilization and embryo trans­fer outcomes in relation to myometrial thickness. J Assist Reprod Genet. 2011; 28(11): 1135-1140.
  15. Zegers-Hochschild F, Adamson GD, de Mouzon J, Ishihara O, Mansour R, Nygren K, et al. The international committee for moni­toring assisted reproductive technology (ICMART) and the world health organization (WHO) revised glossary on ART terminology, 2009. Hum Reprod. 2009; 24(11): 2683-2687.
  16. Levi CS, Lyons EA, Holt SC, Dashefsky SM. Normal anatomy of the female pelvis and transvaginal sonography. In: Callen PW, edi­tor. Ultrasonography in obstetrics and gynecology. 5th ed. Philadel­phia: Saunders; 2008: 887-918.
  17. Benagiano G, Habiba M, Brosens I. The pathophysiology of uterine adenomyosis: an update. Fertil Steril. 2012; 98(3): 572-579.
  18. Exacoustos C, Brienza L, Di Giovanni A, Szabolcs B, Romanini ME, Zupi E, et al. Adenomyosis: three-dimensional sonographic findings of the junctional zone and correlation with histology. Ultra­sound Obstet Gynecol. 2011; 37(4): 471-479.
  19. Kunz G, Herbertz M, Beil D, Huppert P, Leyendecker G. Adenomy­osis as a disorder of the early and late human reproductive period. Reprod Biomed Online. 2007; 15(6): 681-685.
  20. Young RC, Barendse P. Linking myometrial physiology to intrauter­ine pressure; how tissue-level contractions create uterine contrac­tions of labor. PLoS Comput Biol. 2014; 10(10): e1003850.
  21. Killick SR. Ultrasound and the receptivity of the endometrium. Re­prod Biomed Online. 2007; 15(1): 63-67.
  22. Hricak H, Alpers C, Crooks LE, Sheldon PE. Magnetic resonance imaging of the female pelvis: initial experience. AJR Am J Roent­genol. 1983; 141(6): 1119-1128.
  23. Tanos V, Lingwood L, Balami S. Junctional zone endometrium mor­phological characteristics and functionality: review of the literature. Gynecol Obstet Invest. 2020; 85(2): 107-117.
  24. Sfakianaki AK, Buhimschi IA, Pettker CM, Magloire LK, Turan OM, Hamar BD, et al. Ultrasonographic evaluation of myometrial thick­ness in twin pregnancies. Am J Obstet Gynecol. 2008; 198(5): 530. e1-e10.
  25. Chung CHS, Wong AWY, Chan CPS, Saravelos SH, Kong GWS, Cheung LP, et al. The changing pattern of uterine contractions be­fore and after fresh embryo transfer and its relation to clinical out­come. Reprod Biomed Online. 2017; 34(3): 240-247.
  26. Zhu L, Che HS, Xiao L, Li YP. Uterine peristalsis before embryo transfer affects the chance of clinical pregnancy in fresh and fro­zen-thawed embryo transfer cycles. Hum Reprod. 2014; 29(6): 1238-1243.
  27. Kunz G, Leyendecker G. Uterine peristaltic activity during the men­strual cycle: characterization, regulation, function and dysfunction. Reprod Biomed Online. 2002; 4 Suppl 3: 5-9.
  28. Zhu L, Li Y, Xu A. Influence of controlled ovarian hyperstimulation on uterine peristalsis in infertile women. Hum Reprod. 2012; 27(9): 2684-2689.
  29. Kuijsters NPM, Methorst WG, Kortenhorst MSQ, Rabotti C, Mischi M, Schoot BC. Uterine peristalsis and fertility: current knowledge and future perspectives: a review and meta-analysis. Reprod Bi­omed Online. 2017; 35(1): 50-71.