There are different ways in which HRT can be given. The different routes of delivery have different risks associated with them and some women may be strongly advised to take one form of HRT over another due to pre-existing medical conditions. Personal choice also comes into which method would be prescribed.
In addition it is important to note that if a woman is taking combined HRT (with two hormones) then these can be given together in one route or separated out and given by different methods eg oestrogen as a patch and progesterone as a tablet or a combined patch with both hormones.
- Transdermal (through the skin)
This is the safest way to give oestrogen as it has the lowest risk of blood clots and is a bioidentical form of oestrogen which has the same structure as the oestrogen we produce in our own bodies.
Transdermal oestrogen has the advantage that it is absorbed through the skin and thus avoids being broken down in the gut and the liver and may give fewer gastric side effects such as nausea.
It is also a better choice for women who have medical problems that affect their gastrointestinal tract such as Crohn’s disease and ulcerative colitis or in those with liver disease.
The options to take oestrogen in a ‘through the skin’ preparation are via a gel, spray or a patch.
The patches come as oestrogen only or as a combined patch with progesterone. The patches are applied twice weekly and there is a once weekly preparation available in the combined patch.
The spray and gel is oestrogen only and would require separate progesterone if a woman has a womb (and therefore needs both oestrogen and progesterone). The spray and gel are applied daily.
See below for progesterone preparations
- Oral tablets
These can be given as oestrogen alone or in a combined tablet with progesterone and is taken daily.
The tablets are broken down and absorbed in the gastrointestinal tract.
Progesterone can be given through the skin in a combination patch with oestrogen. The progesterone in the patches is a synthetic progesterone (progestogen).
- Oral tablets
Progesterone is available as a combined tablet with oestrogen or can be given separately. Most of the combination tablets contain progestogen (synthetic).
Body identical progesterone (micronized progesterone) is mostly given as a separate tablet but there is one preparation that is a combined tablet with oestrogen.
Micronised progesterone has the same structure as progesterone we produce naturally in our bodies and is made from yams. It is not available as a transdermal preparation as it has not been shown to be safe in protecting the lining of the womb.
- Intrauterine device
The progesterone component of HRT can be given straight into the womb via an interuterine device. The only licensed option for this for HRT in the UK is with a Mirena coil and this can be used for 5 years as part of HRT and of course provides contraception at the same time. Here are other interuterine devices available for contraception but they are not licensed for use as part of HRT.
This is a very low dose of synthetic Progestogen that mostly stays locally in the womb so for many women this option has fewer side effects than other synthetic progestogens in the patches or tablets.