I'm on Alessse birth control and they say that smoking can increase your chances of blood clots... Not sure if they mean weed or cigarettes.
Are both unsafe or just one?
When the birth control package inserts and informative pamphlets talk about the increased risk of smoking on birth control, they refer to tobacco smoking, not marijuana.
It's not yet clear whether marijuana has the same effects when you are using hormonal contraceptives. It's known that smoking pot has many of the same cardiovascular effects as tobacco smoking, and what's more, most folks of course combine tobacco and weed into a joint to smoke pot. But the fact is that research isn't available into the safety of weed while using hormonal birth control.
If you must use pot, maybe consider eating it (in cakes, etc) or using it as tea, to be on the safe side?