When a woman goes on the continuous combined type of HRT where the pill/patch is the same every day the doctor may well say that she "shouldn't" bleed after three months. This really means that "'with any luck" she won't - not that if she does, something's wrong - but scared women have reported on the internet that not only they but their doctors have feared cancer when faced by continued spotting/bleeding beyond this point.

It is easy to show that this worry is probably unfounded if one looks at the full prescribing information for brands of continuous combined HRT. This includes results of studies on a specific drug  which evaluated bleeding profiles over 12 months. The percentages of women achieving cumulative amenorrhea, (which is the state of being bleedfree at a certain point and maintaining this freedom until the end of the study at 12 months) were very far from 100% at 3 months - or even later.
 

	Prempro	Prempro	Femhrt	Ortho-Prefest	Combipatch	Combipatch
1 month	18	22	35	23	9	27
3 month	21	25	50	41	12	33
6 month	26	37	60	35	22	43
1 year	68	78	82	51	54	65

Note 1:There are 2 "Prempro" and "Combipatch" numbers because there are two progestin doses available - the higher progestin variety is more succcessful against bleeding but also produces more unpleasant side effects.

Note 2: Activella reports bleeding patterns differently - i.e numbers of women not bleeding in a specific month (which doesn't necessarily mean that they won't bleed again later) so its numbers are not directly comparable to the ones above. The numbers are : month 1 - 88%, month 3 - 84%, month 6 - 93%, month 12 - 97%. Note that *more* women were bleeding at month 3 than at month 1.

Bleeding on continuous combined formulations can happen at any time.  This inconvenient unscheduled bleeding is more likely to occur in women who are not long past menopause and because of this many doctors tell women that they should use sequential preparations until they are two years postmenopausal. This way, they can be fairly sure of knowing when a regular "period" will occur and can prepare accordingly. Even well after menopause, a woman who continues to bleed anyway will probably prefer the scheduled variety which has the added advantage of having been used since the 1970's so there is some knowledge of its long term effects.

In a recent article, Nand et al: Bleeding pattern and endometrial changes during continuous   combined hormone replacement therapy. Obstet Gynecol 1998;91:678-84, investigated estrone 1.25 mg (Ogen®) with 3 different doses of medroxyprogesterone acetate (Provera®) 2.5 mg, 5.0 mg and 10mg. They recorded how much bleeding 568 women had over 2 years on the different regimens.

At the end of 3 months of therapy 58% of women were amenorrheic while 42% still had some bleeding. At 6 months, 75-80% of women had no vaginal bleeding at all. By 24 months, 90-94% of women were amenorrheic. Almost 10% of women had bleeding no matter what dose of progestin they were taking.

There are various medical guidelines available on the internet which lay out standard procedure for "their" doctors to follow when evaluating bleeding on HRT (continuous or sequential). A very recent one (May 2001) is contained in New Zealand's Best Practice Evidence-based Guideline for the  APPROPRIATE PRESCRIBING of HORMONE REPLACEMENT THERAPY To get this entire guideline, it's necessary to download a book length .pdf file, so I have extracted the flowchart summarising the recommendations for NZ doctors to follow. These recommendations are all based on evidence from good quality studies (references are provided in the document) and are up to date.