Hi Krypto,
Here's a link to a posing by the Mayo Clinic on DVT risk factors:
http://www.mayoclinic.org/diseases-conditions/deep-vein-thrombosis/basics/risk-factors/con-20031922
No mention of herbal estogrens as a factor, but that doesn't mean they are not. I sounds like anything that would promote the clotting of blood is a factor, including nicotine. You might want to consult your doctor if your concern is high. Blood thinners can help prevent clots.
Yes, it's exciting to order that first bottle of PM. Be sure to ramp up gradually to allow time for your body to adjust. What brand of PM did you buy?
Clara