Is There a Difference Between HRT and Birth Control Pills?

I am 50 years old and have been taking HRT for over a year due to a prevalence of hot flushes and night sweats. This year I have tried the oral form of HRT and the patch, and both caused me to have breakthrough bleeding regularly and, most recently, a full cycle. My OB-GYN gave me a uterine biopsy, a transvaginal sonogram, and blood work, and everything was normal. However, at my last visit she told me I have not reached menopause, so the pill would be the best solution to the bleeding. I am worried about the stroke risk for someone my age being on the pill and about missing out on the benefits of HRT.

—Anonymous

It is very possible that you are not in menopause at 50. The average age of menopause in the U.S. is 52. That means that half of women will experience menopause after age 52.

The goal of hormone therapy is to provide a stable level of estrogen all the time. But the estrogen in hormone therapy is typically not enough to suppress ovulation. As a result, if you ovulate and don’t conceive, you will have a period, which can look like breakthrough bleeding on hormone therapy. This bleeding can vary in how heavy it is and can be very irregular.

A combination birth control pill provides estrogen and progesterone similar to hormone therapy but in larger doses. Those larger doses of hormones suppress your body’s signals that drive ovulation, effectively preventing your body from ovulating. This both provides you with contraception (which you need if you are still ovulating) and a stable dose of hormones to manage menopausal symptoms.

In switching to a birth control pill, you are not giving up the benefits of hormone therapy. In fact, oral hormone therapy often contains the exact same estrogen and progestin as some birth control pills, just in smaller doses. In the past, we thought that the large dose of estrogen contained in combination birth control pills was more likely to cause blood clots in women over age 35. But today’s birth control pills contain less estrogen than older ones — and many fewer women smoke, another risk factor for blood clots — and are considered safe for women to take until they are in menopause.

If you wanted to avoid taking birth control pills, though, you could also consider going in a completely different direction. You could continue taking estrogen dosed for hormone therapy in the form of a patch or gel and have a progestin-eluting IUD placed. In that case, the IUD thins the uterine lining (which may eliminate uterine bleeding completely) and provides contraception. The estrogen patch or gel helps stabilize estrogen levels and manages perimenopausal symptoms.

Ultimately, you can benefit from estrogen and progesterone in many forms: hormone therapy, birth control pills, and progestin-eluting IUDs. Where you are in the menopausal transition and the symptoms you are experiencing, as well as your personal preferences, will all inform which formulation is right for you.