Sequential and continuous HRT: what’s the difference?

Different hormone replacement therapy regimens explained

HRT comes in many forms including patches, gels and sprays
Women who still have their womb will need to take progesterone alongside oestrogen
Sequential and continuous HRT regimens explained

HRT comes in many different types and doses. Finding the best approach for you can take adjustments and fine-tuning, and you may find what works for you changes and evolves over time.

One of the first terms you may hear at the beginning of your HRT journey will be whether you are offered combined sequential or continuous HRT. So, what do these terms mean, and what difference does it make?

About oestrogen-only and combined HRT

All types of HRT will contain oestrogen. If you still have your womb, you will need to take progesterone (known as micronised progesterone or a synthetic progestogen) with the oestrogen, as taking oestrogen on its own can thicken the lining of your womb and may increase the risk of uterine cancer. Progesterone helps protect the lining of your womb and keep it thin and healthy [1]. Some women take progesterone after a hysterectomy as it can be a beneficial hormone throughout the body.

Taking HRT containing oestrogen alone is known, not surprisingly, as oestrogen-only HRT, while HRT containing both oestrogen and progesterone is known as combined HRT. Sequential and continuous HRT regimens contain both oestrogen and progesterone.

RELATED: HRT doses explained

What is sequential HRT?

Also known as cyclical HRT, this involves taking oestrogen all the time, and then adding in progesterone for only part of the month. It’s generally used if you are still having periods, or if they have only stopped in the past few months.

With sequential HRT you will typically take oestrogen every day, and then for 12 to 14 days each month you add in progesterone as well. After you finish the progesterone part of your HRT, you will usually have a period-like bleed, which is due to the hormones stopping rather than an actual period.

Using progesterone for half the month primes your body to shed the lining of your womb promptly when you stop taking it. This is called a withdrawal bleed.

Sequential HRT is beneficial if you are still having periods as adding in progesterone all the time at this point can lead to erratic, prolonged and, sometimes, heavy, bleeding.

You can take sequential HRT in many different forms, including skin gels, tablets and skin patches.

What is continuous HRT?

Continuous HRT is when you take your oestrogen and progesterone all the time without a break. If you take tablets, this will be every day, while patches are changed once or twice a week. Continuous HRT is usually used from about a year after your last period or if you have been taking sequential HRT for around 6-12 months

Like sequential HRT, there are many different forms.

Are there any drawbacks to taking sequential HRT?

Women respond very differently to progesterone. So, you may find the part of the month with progesterone makes you feel calm and improves your sleep.

But you may also be among those who are sensitive or intolerant to progesterone, which means the phase where you are taking it can leave you feeling sluggish, bloated and lower your mood. If you do feel like that, speak to your healthcare professional as there are a number of different forms of progesterone, and you are likely to find a version that you can tolerate better.

RELATED: Progesterone intolerance

I’m currently on sequential HRT. Will I change to continuous eventually?

You are very likely to move at some point from sequential to continuous, as it is the safest long-term option for systemic HRT. When this switch happens will be based on lots of individual factors you will discuss with your doctor, including how close to your menopause (12 months after your last period) that you started HRT.

Some women may continue on sequential HRT for longer as they want to continue having periods but other women are keen for their periods to stop. Young women with premature ovarian insufficiency (POI) – menopause under the age of 40 – can also take continuous HRT at a young age.

If you are considering trying to conceive then it is likely you will be recommended to continue taking sequential HRT.

If you are sensitive to progesterone, you may find moving to a low daily dose can be better than sequential, as the switch from having no progesterone to taking it for half the month can trigger symptoms caused by intolerance to the hormone.

References

1. Furness S, Roberts H et al (2012). Hormone therapy in postmenopausal women and risk of endometrial hyperplasia. Cochrane Database Syst Rev. Aug 15;2012(8):CD000402. doi: 10.1002/14651858.CD000402.pub4.