Why Is It Important To Measure Estradiol Blood Levels?

 

3. YOU CAN’T JUST GO BY “HOW YOU FEEL!”

I strongly endorse monitoring estradiol and testosterone blood levels to ensure appropriate dosage and effectiveness of hormone therapy. Monitoring estradiol levels in thousands of women since 1986 has led me to develop more precise hormone regimens producing blood levels comparable to a low physiologic range. As noted earlier, monitoring blood levels is especially important with topical therapy. Most post- menopausal women who see me initially have NEVER had their estrogen level checked!

Early heart disease and osteoporosis are both consequences of low estrogen and have no symptoms in many women. Hot flashes eventually go away in many women even without taking estrogen. Dosing hormones simply by “how you feel” is an archaic notion and other hormones like thyroid hormone and growth hormone are never dosed that way! It is time for menopause management to come into the 21st century and not be treated like a stepchild among other hormone deficiencies. A few lucky women go through menopause and never have hot flashes but this can be a mixed blessing. If you don’t have symptoms, you’re less likely to seek help. However, even without symptoms, you may still be at risk for the degenerative consequences of low estrogen.

For insidious problems like osteoporosis or heart disease, there are usually no symptoms until the woman has a fracture or heart attack. If estrogen dosage for such women is determined simply by “how they feel” we may be giving them an inadequate dose and putting them at increased risk. Objective measurement of blood estradiol ensures adequacy of dosage. Studies have shown a protective effect on bones from fairly low doses of estrogen. In one study of postmenopausal women treated with estrogen alone, those with higher estradiol levels had less progression of subclinical atherosclerosis on CIMT than those with lower estradiol. Recall that CIMT is an ultrasound measurement of the thickness of the two inner layers (the intima and media) of the carotid arteries that the American Heart Association recommends as the best way to screen for early risk of heart disease or stroke. I routinely rely on CIMT to assist me in assessing these risks in my patients.

In general, creams and gels produce lower blood estradiol levels ranging from 9.8 to 30 pg/ml that are similar to the lower doses of estradiol patches. The highest estradiol blood levels are achieved with the 0.1 mg estradiol patches and are typically in the range of 80 pg/ml.

More studies need to be done to determine the optimal level that protects us from the consequences of low estrogen while avoiding the adverse effects that may occur with the higher doses of estrogen. For the time being, a reasonable approach is to give the lowest estrogen dose that relieves symptoms and still falls within the lower physiologic range for a premenopausal woman.

 

4. IMPORTANCE OF ACCURATE BLOOD ASSAYS

When measuring estradiol levels it is very important that an assay be utilized which has the ability to detect the very low levels present in post-menopausal women. The estradiol assay used in fertility practices for women undergoing ovulation induction or in vitro fertilization is not appropriate. An assay with sensitivity at the low end of the scale is required to monitor estradiol therapy in menopausal women. The assay should be capable of measuring less than 1.5 ng/dL of estradiol or less than 1.0 pg/ml of free estradiol. Similarly for free testosterone, assays that utilize equilibrium dialysis are the most accurate at detecting the lower levels of testosterone seen in women.

When I first see a female patient, I may check estradiol blood levels several times in the first few months while adjusting their dosage. Once the levels are stable, I check them once a year unless symptoms develop or there is another dosage change. Since postmenopausal ovaries often continue to product testosterone, it is important to document low testosterone levels before prescribing testosterone.

For a woman with an intact uterus, withdrawal periods on cyclic progesterone and a normal yearly TVS, there is less need to monitor progesterone. “Withdrawal periods” is the medical term given to the monthly menstrual flow occurring in postmenopausal women prescribed estrogen with cyclic progesterone. When a woman is perimenopausal and still having periods, progesterone levels on day 21 of her menstrual cycle are a useful indication of her endogenous progesterone. If low, adding progesterone therapy may improve symptoms of heavy bleeding, PMS or insomnia.

5. SALIVARY HORMONE TESTING IS NOT RELIABLE

Many women ask me about salivary hormone tests. While dependent on the accuracy of the testing laboratory, you can measure hormone levels of estradiol, progesterone and testosterone in saliva. However, an important reason for measuring hormones is to be able to determine the optimal dose of the hormone preparation. Salivary hormone tests are notoriously unreliable for this purpose. Numerous studies have shown inconsistent and skewed results with the use of salivary hormone testing in women on HRT. That’s why I utilize blood hormone testing.

RECAP WHY IS IT IMPORTANT TO MEASURE ESTRADIOL BLOOD LEVELS? BLOG SERIES

WHY IS IT IMPORTANT TO MEASURE ESTRADIOL BLOOD LEVELS? PART 1


 

The content of this blog series is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. This blog series may discuss nutritional products and protocols that have not been evaluated by the U.S. Food and Drug Administration. These products or the information contained on this website is not intended to diagnose, treat, cure or prevent any disease. All website content is © Copyright 2012 by Marina Johnson MD – All Rights Reserved

Excerpt from “Outliving Your Ovaries” © 2012 by Marina Johnson MD. Dr. Johnson was a medical writer and pharmacist before medical school and utilized these skills to research 450 medical journal articles to develop her book. She has no financial conflicts of interest or ties to any pharmaceutical company. Her only objective is determining the most effective, safest therapy for patients.

To obtain a copy of “Outliving Your Ovaries” click here

 

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All website content © Copyright 2011 by Marina Johnson, M.D., F.A.C.E. - All Rights Reserved

The content of this website is for informational purposes only and is not intended to be a substitute for professional medical advice,diagnosis or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. This website may discuss nutritional products and protocols that have not been evaluated by the U.S. Food and Drug Administration. These products or the information contained on this website is not intended to diagnose, treat, cure or prevent any disease.