On Cycle day 10 of my 3rd IUI cycle I had my routine ultrasound. My uterine lining was measured at 5.1mm. The nurse was concerned. She stated I will need to have another ultrasound on the day of IUI to measure my lining again. Being the typical type A infertile that I am, of course I turned to “Dr. Google”. I read many blog posts and forums but nothing was giving me more than anecdotal evidence and guesses, which aren’t really reliable sources. So I turned to scholarly articles. These are very technical and some times tedious to comprehend.
I wanted to know:
- What is considered “Thin lining”?
- Does Thin lining hinder implantation / healthy pregnancy / live birth?
- What causes Thin lining?
- What can be done to prevent thin lining?
Here is what I’ve found (disclaimer: I am not a doctor, the following information should not be mistaken for medical advice. I’ve written this post to try to digest information for myself into a more useable “laypersons” source. This is my source)
What Is Considered “Thin Lining”
Thin uterine lining is generally accepted as less than 7 mm of endometrial thickness. Thin endometrial lining is not commonly found in ART cycles only 2.4% of patients, but statistically increases greatly with age.
“An incidence of 5% has been reported in women <40 years and 25% beyond age forty in natural cycles. Kasius et al. 2014 reported an incidence of 2.4% in their meta-analysis that included 1170 patients undergoing IVF.”
Estrogen causes the endometrial lining continues to grow until the LH surge.
This makes me hopeful that I still have a few more days to develop a thicker lining before IUI.
Does Thin Lining Hinder Implantation, Healthy Pregnancy, Or Live Birth.
From what I understand, according to the source I have read (which has 40 sources itself), thin lining doesn’t significantly prevent implantation. But women with thin lining have higher miscarriage rates and lower live birth rates. It’s not just about “thickness” though. An ideally developed endometrial lining with have an appearance on an ultrasound of 3 layers on the day of ovulation -or “trilaminal”- (Source refers to it as EnP). Research has shown that thin lining that appears in 3 layers is still possible to have pregnancy, but odds of live birth are decreased. In a study of 5573 patients undergoing IVF, women with uterine lining less than 7 mm clinical pregnancy rate was 26%, but thicker lining 7+ mm was 51%. Miscarriage rate for the thin lining group was higher at 31%, versus the thicker group was 17%. It’s important to know that these numbers are “not of statistical significance” (the P-value is less than .05). All that being said the sources conclusion was “One can conclude from this review that Eth (endometrial thickness) can give us probability but cannot be predictive of pregnancy.” (Source)
What Causes Thin lining?
“Thin endometrium can result from various factors the most common being inflammatory and iatrogenic. Poor vascularity and low estradiol values can also lead to poor endometrial growth. The endometrium can also be inherently thin in some women.”
Inflammatory Acute or chronic infection can lead to the destruction of the basal layer of the endometrium. This is believed to be the most common cause and is hard to fix. The body repairs damaged endometrial tissue through “fibrosis” which destroys the base layer that produces the lining cells.
Iatrigenic- Surgical or medical in nature, either through D&C or surgical procedures to remove polyps and other not good things. Also frequent use of Clomid.
Idiopathic- “Unknown origin”, not caused by disease. Basically saying that’s just how it is some times for certain women.
What can be done to prevent thin lining, or increase thickness?
There is no proven answer. “Numerous treatments have been tried to improve refractory endometrium, but success has been limited. Currently, evidence-based medicine has not validated any specific treatment. ” The research goes on to list current popular treatments.
- Intra-uterine granulocyte colony-stimulating factor
- Extended Estrogen Support
- Human chorionic gonadotropin priming in the follicular phase
- Drugs that increase endometrial blood flow have been administered individually or in combination to improve Endometrial thickness.”None of these therapies have been met with much success
My opinion/ conclusion:
There are many dietary suggestions for foods/herbs that increase blood flow, if a thin lining can be caused by decreased vascularity it makes sense to consume food/herbs that are linked to increased blood flow. Herbs like red raspberry leaf tea, green tea and ginger root. Exercise improves blood flow too! Over the counter options like vitamin E supplements, L-arginine and low dose aspirin might be a good option as well. Although nothing is “proven” doesn’t mean it can’t work for you, especially if there is no negative risk associated with diet, exercise, herbs, and safe OTC options. Obviously you should ask your doctor before starting any medications/supplements/herbs.