The endometrium, the uterus’ inner lining, varies in thickness throughout the different phases of the menstrual cycle. Endometrial thickness directly impacts embryo implantation. After an egg is fertilized, the developing embryo travels down the Fallopian tube to the uterus where it needs to implant. An optimal thickness of the uterine lining is preferable for successful implantation and to provide a nourishing environment to sustain pregnancy. Performing a transvaginal ultrasound is the most common way to measure endometrial thickness This is measured with a transvaginal ultrasound. Typically, a range between 7 to 10 mm that has a three-layered or trilaminar appearance in the ultrasound is considered favorable for implantation. An endometrial lining that is too thin or thick can lead to implantation failure and early pregnancy loss.
Some causes for very thin endometrial lining can include:
- Estrogen deficiency: Estrogen deficiency during the menstrual cycle’s follicular phase can cause inadequate endometrium thickening.
- Age: As women get older and approaching menopause, the endometrium lining may become thinner and less receptive to embryo implantation.
- Uterine Fibroids or Polyps: Noncancerous growths in the uterus can interfere with endometrial development and reduce its thickness.
- Anovulation: Irregular or the absence of ovulation can impact the estrogen and progesterone levels that help with proper endometrium growth.
- Poor Blood Flow: Inadequate blood flow to the uterus can limit the endometrial lining growth and development
- Chronic Endometritis: Infection of the endometrial causes inflammation that leads to thinning of the endometrial lining and interferes with embryo implantation.
- Adhesions and Scar Tissue: Uterine surgeries and procedures as well as illnesses, infections, and trauma that cause adhesions and scarring can damage the endometrium and result in its thinning.
- Medical Treatment and Medication: Specific medical treatments and medication can adversely impact the endometrial lining growth and development.
Endometrial hyperplasia is rare and more likely to occur in older women in perimenopause or menopause. Those who have the condition can be at risk for developing endometrial cancer.
Endometrial thickness is only one factor that influences fertility and successful embryo implantation. Other factors including embryo health as well as the reproductive and overall health of a woman play important roles in conception and achieving a pregnancy. For those looking to conceive or need help in starting a family, scheduling a consultation and getting your reproductive health and fertility evaluated by a fertility specialist is the first step.