HRT: Combined or Estrogen only

HRT – Combined or Estrogen only

HRT when taken orally as a tablet, or across the skin as a patch, gel or spray, is called systemic – this means that it travels all throughout the body. This is called combined if both an estrogen and a progestogen are taken, or estrogen only if a progestogen is not needed.

When estrogen is used only in the vagina as a tablet, cream, pessary, gel or ring, this is called localised treatment as the effect is observed locally in the vagina and bladder with very little hormone travelling throughout the body.

Combined HRT

For the relief of symptoms caused by low or fluctuating estrogen, women require estrogen replacement. If the woman has a womb (uterus), she will also require a progestogen. This is called combined HRT. Combined HRT is taken in one of two ways:

Sequential (cyclical) HRT

If you have had a period in the last 6-12 months, you will be recommended to have sequential HRT. This involves taking estrogen every day and a progestogen for 12-14 days out of every 28. For simplicity, women are usually advised to take the progestogen in a pattern of 2 weeks on, 2 weeks off. This will usually result in a monthly bleed. If a monthly bleed is not wanted, a Mirena coil can be considered. Once it has settled, most women experience light or no bleeding with the Mirena coil. It can be particularly useful in the perimenopause when periods can be heavy and when contraception is often still required. The Mirena can be used as part of HRT for 5 years after which it should be replaced.

Continuous Combined HRT

If your last period was 12 months ago or more, you will be recommended to start continuous combined HRT. This involves taking both estrogen and a progestogen every day. On starting this combination, some vaginal bleeding is common but usually settles within 3-6 months after which, no bleeding is expected.

Estrogen Only HRT

Women who have had a hysterectomy (womb removed) take estrogen only HRT and this is taken on a daily basis. The absence of the womb means that a progestogen is not required to protect the lining (the endometrium).

There are a few exceptions to this rule:

  • Endometriosis. Many women have a hysterectomy as treatment of their endometriosis but often some patches of endometriosis are left in the pelvis as they have proven difficult to remove safely. In these women, their gynaecologist will often recommend that they take a progestogen as part of their HRT to avoid the risk of the remaining patches being stimulated by the estrogen. Women with a history of endometriosis are usually given a progestogen daily.
  • Subtotal hysterectomy. At hysterectomy, some women opt to keep the cervix rather than have all of the womb removed. In these women, some of the womb lining (endometrium) may remain. If this is the case, combined HRT with both estrogen and a progestogen is required to avoid thickening of the remaining endometrium.
  • Endometrial ablation. This is a procedure that destroys the lining of the womb. It is used as a treatment to reduce menstrual blood loss in women who have heavy periods. In some women, periods stop completely. However the lining of the womb is not totally removed. Women who have had an endometrial ablation require combined HRT.

Localised Vaginal Estrogen

Women who have symptoms of vaginal dryness, soreness, itch, pain on intercourse, passing urine more often, recurrent urinary tract infection and getting up to pass urine in the night can benefit from the use of vaginal estrogen. These symptoms result from a lack of estrogen in the tissues of the bladder, vagina, vulva and pelvic floor and together are called Genitourinary Syndrome of Menopause. By using estrogen in the vagina as a tablet, gel, pessary, cream or ring, these symptoms can be relieved. Only a tiny amount of estrogen is absorbed into the body so no progestogen is required.

Local vaginal estrogen can safely be used in combination with systemic HRT if required for symptom control.

Dr Alice Duffy

Last updated May 2021

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