HRT is hormone replacement therapy. This generally means the hormones a woman produces less of as she approaches the menopause and transitions through it.
The hormones which may need to be replaced are oestrogen (estradiol), progesterone and testosterone.
Oestrogen is used to alleviate menopausal symptoms, protect against bone loss and reduce the risk of heart disease.
Oestrogen replacement can be given as tablets, patches, gel or spray. All of these preparations get into the bloodstream., so it is distributed throughout the body. Oestrogen from patches, gel and spray are absorbed directly through the skin. This means that it bypasses your liver and causes less side effects. Your liver produces clotting factors, which are affected by oral oestrogen causing a small increased risk of a blood clot occurring. This risk of clot is not present however, in women who take oestrogen through the skin as a patch, gel or spray.
Oestrogen can also be used topically, direct to the vagina for relief of vaginal symptoms such as itching, dryness, soreness during intercourse and bladder symptoms such as frequency and urgency. Preparations include pessaries, cream and ovules which are inserted either using an applicator or a finger. As absorption into the bloodstream is negligible, these preparations do not increase breast cancer risk. They can be used by almost all patients.
If you still have your womb it is necessary to take progesterone or a synthetic equivalent (progestogen) in addition to the oestrogen. This is because oestrogen alone can increase the thickness of the lining of your womb and cause a slight risk of the cells becoming cancerous. Taking progesterone reduces this thickening effect – and therefore the risk. The progestogen is usually given as a tablet, but it can also be given in the form of a coil inserted into your womb (uterus) or transdermally as a patch in combination with oestrogen.
If you have passed your menopause HRT is likely to be given as continuous combined HRT (CCHRT) This means the lining of the womb is prevented from building up and does not need to be cleared in the form of a bleed. If you are still seeing periods, or are within one year of your last period, it may be that CCHRT would cause irregular and unacceptable bleeding, so sequential combined HRT is given instead. For all sequential preparations, unopposed oestrogen is given for about 2 weeks, followed by oestrogen with progesterone for the next 2 weeks, in a cycle. This usually results in a bleed around the end of the progesterone dose.
The safest type of progestogen is an oral capsule called micronised progesterone. This is a body identical type of progesterone, as it has the same molecular structure as progesterone naturally produced in your body. It is derived from yams. Micronised progesterone is associated with a lower risk of breast cancer, compared to women taking the synthetic types of progestogens. It can be taken as two capsules together, for two out of four weeks in women who are still having periods, or taken as one capsule each evening, for a period-free HRT regime.
There are other types of progestogens which are synthetic and not body identical.
Synthetic progestogens may cause side effects such as breast tenderness, bloating and mood swings. They may not be so metabolically friendly (effect on heart, cholesterol, diabetes etc) and seem to carry a higher risk of breast cancer than the body identical micronised progesterone and body similar dydrogesterone. Often changing the type of progestogen can help to reduce side effects or improve a bleeding pattern.
Progesterone and the progestogens come in oral form, with the exception of levonorgestrel, which is available combined with oestrogen in a patch and also in a coil. The Mirena coil provides the necessary progestogen needed to combat thickening of the womb lining, and it is also a very effective method of contraception for women who require this. It can be used as the progestogen component of HRT for five years and then can be replaced after this time.
Another form of HRT, tibolone, works as a continuous combined preparation. It differs from the other preparations in that the one drug has oestrogenic, progestognenic and androgenic (testosterone -like) activity. It can be useful in women who are experiencing reduced libido. It is can also be helpful for women who have had endometriosis.
Oestrogen and the range of progesterone and progestogens are available separately or formulated into a range of different brands of sequential or combined HRT. This includes the combination patches containing progestogen and oestrogen. It is important to tailor the HRT to each woman’s needs and preferences.
Testosterone is also a female hormone! Before the menopause, the ovaries produce more testosterone than oestrogen. It is also produced in the adrenal glands. It is an important driver of libido and sexual arousal, as well as necessary for bone health, cardiovascular health, cognitive wellbeing and energy levels. Particularly in women who have undergone an early menopause and even more so if it was a surgical menopause, testosterone supplements may be appropriate. If women still have symptoms such as low libido once their other symptoms have been treated with oestrogen, testosterone supplementation may help.