Risks of HRT

Often women are very worried about the risks of HRT. While we have to be aware of the risks, they are actually very infrequent.

Breast cancer risk:

Research has shown that use of HRT is associated with a small increased risk of breast cancer. However, this risk has been estimated to be a rare risk factor, about 1 in 1000 women years. This risk may depend on the duration of use of HRT and the dose.

We need to take a few things in perspective.

Most women have a low lifetime risk of breast cancer.
Most women will not be diagnosed with breast cancer due to HRT use.
When HRT is used for premature menopause, the year of exposure should be counted from the age of 50 years and not from the age when HRT is started.
There is no increased risk with use of Oestrogen only HRT (in women who have had hysterectomy). Some research show that Estrogen only HRT may actually reduce breast cancer risk.
Combined HRT may be associated with small increased risk.
Certain lifestyle risk factors like obesity and alcohol use are associated with even higher risk of breast cancer. Hence, healthy lifestyle choices can help reduce the breast cancer risk.

British Menopause Society has produced a lovely document tabulating the risks stated by various studies and comparing with obesity and alcohol intake. We can see for ourselves that the risks are minimal and can be mitigated by positive lifestyle changes.

Thrombosis risk (risk of developing clots in legs or lungs):

Certain types of HRT can be associated with increased risk of developing clots.

This only applies to combined oral HRT, or oral estrogen. Estrogen taken in tablet form, it passes through the liver and activates the clotting factors which effect blood clotting. The risk might be 2-4 times higher than baseline.

Transdermal HRT (estrogen in patch, gel, spray, or implant form) does not increase the risk of clots.

Stroke Risk:

There is no increased risk of stroke if HRT is started before the age of 60 or within 10 years of menopause. However, it was noted that there might be slightly higher risk of stroke if HRT is started more than 10 years after menopause.

Heart disease or Cardiovascular risks:

There is no evidence that HRT increases the risk of heart disease in women under the age of 60. Even in older women above 60, current evidence suggests that starting HRT even later in life does not increase the risk of heart attacks or heart disease.