Hi, Endometrium is the inner layer of the uterus where the fertilized egg would implant and develops into fetus. The menstrual cycle is the process of development of egg and release of egg which may or may not get fertilized along with development of uterine endometrium for implanting fertilized egg. If the egg in not fertilized, the developed endometrium sheds and menstruation begins. Follicle Stimulating hormone and luteinizing hormone are the two major hormones controls the levels of estrogen and progesterone which in turn controls the developmental changes in the body to become pregnant. Endometrial thickness of up to 13mm is normal in young age group. On increasing age, the thickness may up to 16mm. The level of hormones play major role in these changes. Simple hyperplasia is not cancerous lesion. Atypical hyperplasia can develop into cancer. Management depends on the age group, pregnancy, menopause and other risk status. Hysterectomy is also advised in some individuals. Visit a gynecologist with the Ultrasound report for further evaluation. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Pradeepraj, General & Family Physician