Pathophysiologic features of "thin" endometrium

Fertil Steril. 2009 Apr;91(4):998-1004. doi: 10.1016/j.fertnstert.2008.01.029. Epub 2008 Mar 6.


Objective: To characterize pathophysiologic features of a "thin" endometrium.

Design: A prospective observational study.

Setting: University Hospital and City General Hospital.

Patient(s): Patients with normal-thickness endometrium (Normal-Em group: endometrial thickness >or=8 mm; n = 57) and thin endometrium (Thin-Em group: endometrial thickness <8 mm; n = 17).

Main outcome measure(s): Blood flow impedance of the uterine radial artery (RA) was assessed as resistance index (RI) by transvaginal color-pulsed Doppler ultrasonography. The area of glandular epithelium, the number of blood vessels, and vascular endothelial growth factor (VEGF) expression were examined in the midluteal-phase endometrium.

Result(s): The RA-RI in the Thin-Em group was significantly higher than in the Normal-Em group throughout the menstrual cycle. Endometrial thickness was significantly correlated with RA-RI. Growth of glandular epithelium, the number of blood vessels, and VEGF expression were significantly lower in the Thin-Em group than in the Normal-Em group.

Conclusion(s): A "thin" endometrium was characterized by high blood flow impedance of RA, poor epithelial growth, decreased VEGF expression, and poor vascular development.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Vessels / pathology
  • Cell Count
  • Endometrium / blood supply
  • Endometrium / diagnostic imaging
  • Endometrium / metabolism
  • Endometrium / pathology*
  • Estradiol / blood
  • Female
  • Humans
  • Infertility, Female / blood
  • Infertility, Female / diagnostic imaging
  • Infertility, Female / etiology
  • Infertility, Female / pathology*
  • Organ Size / physiology
  • Progesterone / blood
  • Prospective Studies
  • Regional Blood Flow
  • Stromal Cells / metabolism
  • Stromal Cells / pathology
  • Ultrasonography
  • Uterus / blood supply
  • Uterus / pathology
  • Vascular Endothelial Growth Factor A / metabolism
  • Young Adult


  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Progesterone
  • Estradiol