Myths 4 to 6
Myth 4: There is an increased risk of breast cancer with all types of HRT
This is the risk that most women worry about with HRT. You may have a small increased risk of breast cancer if you take some types of HRT. However, if you are taking oestrogen-only HRT (so if you have had a hysterectomy) then you do not have an increased risk of breast cancer. There are many risk factors for developing breast cancer. Women who are overweight, drink alcohol, smoke, or undertake little or no exercise all have a higher risk of developing breast cancer. The increased risk of breast cancer is associated with women who take certain types of combined HRT (oestrogen and a progestogen) and this risk increases the longer you take HRT for. This risk appears to be lower with some types of progestogens compared to others. When you stop taking HRT, any increased risk of breast cancer reduces.
The actual risk of breast cancer with taking combined HRT is very small. The risk is actually less than the risk of breast cancer in women who are obese and in those women who drink two to three units of alcohol each day. There is no evidence that taking HRT increases a woman's risk of dying from breast cancer.
Note: There is no increased risk of breast cancer in women who take HRT under the age of 51 years (see later myth).
Myth 5: HRT causes clots
This is false for some types of HRT. If you take oral (tablet) HRT then there is a small increased risk of a clot developing in your leg or lungs. This increased risk is very small and is higher if you have other risk factors for developing a clot such as obesity or a having a history of a clot in the past.
However, if you take the oestrogen part of HRT as either a gel or a patch then it gets absorbed directly into your body which means that the clotting factors in your liver are not activated (which they are when you swallow a tablet) and then this is not associated with an increased risk of clot.
Myth 6: HRT will cause heart attacks and strokes
Taking HRT when you are under 60 years of age does not actually increase your risk of developing a heart attack. Those women who only need to take oestrogen (without a progestogen) actually have a lower risk of heart disease compared to women who do not take HRT. There is a very small increased risk of stroke in women who take combined HRT but this risk is reduced by using the oestrogen as gels or patches. The risk of stroke in women under 60 years is very low, however, regardless of whether or not you take HRT.