Q: My “insurance plan” doctor tells me I shouldn’t take estrogen—even bio-identical estrogen—because it will increase my risk of a blood clot and maybe a stroke. Is this true?

––CS, via e-mail

Dr. Wright: Unless you use the enormous estrogen quantities found during pregnancy or use the wrong delivery method that’s absolutely NOT true! Study after study has demonstrated that while taking estrogen orally increases blood clotting tendencies, using estrogen transdermally (or even better, transmucosally) does not increase blood clotting.

But just to put your mind at ease and to monitor the safety of the transdermal/transmucosal estrogen and estrogen metabolites involved in bio-identical hormone replacement therapy, it’s always a good idea to do the 24-hour urine test featured in detail in the December 2007 issue of Nutrition & Healing.

And there’s also anti-clotting “insurance,” natural-style. Attention was first drawn to the anti-clotting and anti-atherosclerotic capabilities of fish oil when scientists observed that Greenland Eskimos (Inuit) have much lower incidence of coronary atherosclerosis than people in other areas of the world. They eventually traced this phenomenon back to consumption of large quantities of fish oil.

Of course, they also discovered that a sub-group of Inuit also had a significantly higher risk of hemorrhagic stroke (caused by bleeding into the brain), despite having a lower risk of atherosclerosis. The increased stroke risk was traced to consumption of excess fish oil. Further research showed that if anyone—Inuit or not—ate or took the equivalent of 6 tablespoons of fish oil daily, and then cut themselves, they wouldn’t stop bleeding at all, unless enormous pressure was applied to the site of the cut.

Conclusion: fish oil is an excellent anti-coagulant, but watch the dose!

If you’re concerned about abnormal clotting tendencies (perhaps there’s a history of blood clot or stroke in your family), have a blood sample drawn and checked by a specialty “coagulation lab” for abnormal clotting tendencies. (Your doctor should be able to refer you to a coagulation lab in your area.) If your sample shows any of these tendencies, hold off on the estrogen until you take a healthy quantity of fish oil (1 1/2 tablespoonfuls, twice daily, along with 400 IU of mixed tocopherols twice daily) for three to four weeks, and then have the test done again.

If your abnormal clotting tendencies are better, that’s that: You can start taking bio-identical hormone replacement therapy and continue your daily fish oil and vitamin E supplements. If not, increase your fish oil intake, or add other natural (and harmless) anti-coagulants such as ginkgo, niacin, etc., and repeat the testing until you’ve achieved your goal.

Obviously, it’s best to work with a physician skilled and knowledgeable in natural and nutritional medicine if you’re concerned about increased risk of a clot, but the bottom line is that there’s very little reason to worry if you’re using transdermal estrogens in quantities no greater than what were in your body when your ovaries were making your own.