Bleeding on HRT: what to expect and when to call

You went through menopause, your periods stopped, and now you are spotting again. If you have started hormone therapy, that may be expected. It may also be a sign that something needs a closer look. The difference depends on your schedule, how long you have been taking it, and what the bleeding looks like. Here is how to tell the two apart.

Why hormone therapy can cause bleeding

Estrogen makes the lining of the uterus, the endometrium, grow. Taken alone by a woman who still has a uterus, it raises the risk of endometrial hyperplasia and endometrial cancer ^[1]. ACOG explains that when the lining becomes too thick, its cells can in some cases become abnormal and lead to cancer ^[7]. That is why women with a uterus who take systemic estrogen also take a progestogen ^{[1, 10]}.

The protection is substantial. In a 3-year trial described on the label for Prometrium, an FDA-approved micronized progesterone, 64% of women taking estrogen alone developed endometrial hyperplasia, compared with 6% of women taking estrogen with cyclic micronized progesterone ^[5].

The progestogen protects the lining, but how it is scheduled shapes the bleeding you see. The Menopause Society notes that sequential and continuous combined regimens may differ, and that many women choose regimens that avoid periodic bleeding ^[1].

Cyclic vs continuous combined: two bleeding patterns

Cyclic, or sequential, therapy means estrogen every day, with a progestogen added for part of each month. One FDA-approved regimen uses micronized progesterone 200 mg at bedtime for 12 days of each 28-day cycle ^[5]. The Menopause Society gives a similar example: 200 mg a day for 12 to 14 days a month ^[1].

Continuous combined therapy means estrogen and a progestogen every day, with no break ^[2].

A 1-year randomized trial of 1,724 postmenopausal women compared the two approaches, using conjugated estrogens with medroxyprogesterone acetate ^[2]:

In plain terms, cyclic therapy tends to bring a predictable monthly bleed, while continuous combined therapy tends to bring irregular bleeding at first that often settles down ^[2].

That trial is a good reminder of two things. A daily estradiol and progesterone schedule left most women without bleeding by the end of a year, and a higher estrogen dose came with more bleeding ^[4]. Even on placebo, about 1 in 5 women reported some bleeding or spotting ^[4].

Bleeding in the first months

Bleeding early on is common. In the WHI, 51% of women taking a daily estrogen plus progestin pill reported vaginal bleeding at 6 months, compared with 5% on placebo, and most of it was spotting ^[3]. ACOG lists vaginal spotting or bleeding as a side effect of hormone therapy that usually stops within 6 months ^[6]. The Menopause Society also lists breakthrough bleeding among the more common side effects ^[1].

Bleeding can lead to more than inconvenience. In the WHI, women on the combination were more likely to have a dilation and curettage, a procedure that removes cells from the uterine lining for testing ^[7]: 5.4% compared with 2.4% on placebo ^[3].

If early spotting bothers you, or goes on longer than expected, ACOG suggests talking with your ob-gyn, since adjusting the dose may be an option ^[6]. Do not change your dose on your own.

When bleeding needs to be checked

The Menopause Society says unscheduled bleeding that occurs more than 6 months after starting combined hormone therapy should be investigated ^[1]. It also says bleeding after menopause must be evaluated thoroughly in any woman, whether or not she uses hormone therapy, because it may be a sign of endometrial hyperplasia or cancer ^[1]. ACOG lists bleeding after menopause as a form of abnormal uterine bleeding ^[8].

FDA labeling for an approved estradiol and progesterone capsule tells women to report any vaginal bleeding to their healthcare provider as soon as possible, and notes that vaginal bleeding after menopause may be a warning sign of cancer of the uterus ^[4].

Contact your clinician promptly if:

• Bleeding starts more than 6 months after you began combined therapy and is not part of a planned schedule ^[1].
• On a cyclic schedule, bleeding comes at an unexpected time rather than with your usual withdrawal bleed ^[1].
• You had stopped bleeding on continuous therapy and bleeding comes back ^[1].
• You use only low-dose vaginal estrogen and notice any bleeding ^[1].
• You notice any bleeding after menopause, from light pinkish or brown spotting to a heavy flow like a period ^[7].

Do not stop or change your hormones on your own because of bleeding. Call your clinician first, so the cause can be checked and your plan adjusted if needed.

What an evaluation involves

According to ACOG, an evaluation usually starts with questions about when you went through menopause, which medications you take, and your other health conditions, followed by a pelvic exam ^[7]. Next steps may include a pelvic ultrasound to look at the uterine lining, a biopsy to sample it, or both ^[7]. Some cases call for a hysteroscopy, where a thin camera looks inside the uterus, with dilation and curettage ^[7]. ACOG's list of tests for abnormal uterine bleeding also includes sonohysterography, an ultrasound with fluid placed in the uterus ^[8].

Causes include thinning of the vaginal and vulvar tissue after menopause, polyps, and a lining that has become too thick ^[7]. Cancer is the most serious cause, but also the least likely ^[7]. In a review of 129 studies, about 9% of women with postmenopausal bleeding were diagnosed with endometrial cancer, while about 91% of women with endometrial cancer had postmenopausal bleeding ^[9]. That is why bleeding is worth checking, even though most of the time it turns out to be something else ^[9].

Why the progestogen dose and schedule matter

Bleeding patterns also reflect how well the lining is protected. In a Cochrane review, estrogen without a progestogen raised the rate of endometrial hyperplasia at every dose studied, while low-dose estrogen taken continuously with an adequate progestogen did not differ from placebo at 2 years ^[10]. The review concluded that women with a uterus who use hormone therapy should take both ^[10].

The Menopause Society notes that, with long-term use, observational studies suggest a possibly higher risk of endometrial cancer with cyclic progestogen schedules than continuous ones, and with micronized progesterone than with other progestogens ^[1]. That is one reason it says oral micronized progesterone must be adequately dosed ^[1]. For more, see progesterone side effects and progesterone without estrogen.

Bleeding questions and WarriorBabe Health

If you have a uterus, a WarriorBabe Health clinician may pair estrogen, such as oral estradiol, an estradiol patch, or estradiol cream, with a progesterone capsule taken at bedtime. Ask your clinician which bleeding pattern to expect on your plan, and contact your care team about any bleeding you did not expect. Compare options on our hormone treatments page.

Our hormone products are compounded by a licensed pharmacy. Compounded drugs are not FDA-approved, which means the FDA does not review their safety, effectiveness, or quality before they are marketed ^[11]. The bleeding data in this article come from studies of approved products.

Wondering whether hormone therapy might be right for you? Take the 2-minute quiz. A licensed clinician makes the final call on whether any prescription is appropriate.

This article is for general information. It is not medical advice and does not replace a visit with a licensed clinician who knows your history. Do not start, stop or change a medication without talking to your clinician. If you think you are having a medical emergency, call 911.