Books about menopause often seem to imply that the only forms of HRT available are Premarin (an oestrogen isolated from the urine of pregnant mares) and Pro vera (a progestogen of long standing). It is certainly true that the most common mix of hormones prescribed as HRT is an oestrogen (taken in every day by pill, patch or implant), plus a progestogen (taken daily for ten to fourteen days, then not used for the rest of the month), but the numerous options available mean that hormone formats can be tailored to meet each woman’s needs.
COMBINED CYCLICAL THERAPY Many varieties of oestrogen and progestogen can be used in this combined hormone format, referred to as cyclical progestogen. The oestrogen component is the main agent for relieving menopausal symptoms, while the addition of a certain amount of progestogen puts the brakes on growth of the endometrium. A withdrawal bleed occurs when you stop taking progestogen.
“ For women taking separate hormone pills (for example, because the doctor wants to use dosages not found in the available combined-pill formats), an easy way to remember when to start the progestogen is at the beginning of each calendar month. The progestogen is then stopped on the tenth, twelfth or fourteenth day of the month (depending on the doctor’s instructions). You could, on the other hand, use a ‘calendar dial pack’, which contains ten oestrogen-plus-progestogen tablets followed by eighteen oestrogen pills.
You can expect a withdrawal bleed to begin anywhere between the tenth day of taking progestogen and a week after it is finished. If bleeding starts outside this time (that is, before day ten or after day seventeen, nineteen or twenty-one, depending on how many days the progestogen is taken), it is likely that the hormone dose is inadequate and needs to be altered. Most women taking progestogen for ten to fourteen days a month (that is, cyclical progestogen) have a withdrawal bleed each month at the end of the progestogen phase. The first few bleeds tend to be heavier than later bleeds. In about 50 per cent of women taking this cyclical progestogen, withdrawal bleeds disappear after about ten years; in most other users, withdrawal bleeds continue for however long the hormones are taken, usually becoming lighter with time.
In a small proportion of users, of whom Marita is an example, cyclical progestogen therapy never causes bleeding. The absence of bleeding after she started taking oestrogen and progestogen caused Marita some initial concern, but she was reassured by her doctor that nothing was amiss. She then wondered whether she needed to take progestogen at all, but her doctor impressed on her the necessity of continuing with this part of the therapy as she still had a uterus, which would be at increased risk of abnormal tissue growth, and possibly cancer, if she took oestrogen alone. Provera is the progestogen best documented as preventing abnormal growth of the endometrium.