This is part 1 of a three-part countdown to World Menopause Day on Sunday 18 October 2026. Everything about the day itself, including this year's theme and five practical things you can do, is in my World Menopause Day guide. Part 1 is about why HRT is so easy to lose track of. Part 2 covers this year's theme, and part 3 asks how you know if your HRT is actually working.
If you've ever stood in the bathroom wondering whether you changed your patch on Tuesday or Wednesday, this one's for you. (How that exact moment led me to build an app is its own story, told in why I built HRTMe.)
Two or more medicines is the usual set-up
Ask someone to picture HRT and they'll often picture one tablet a day. For many of us it looks more like a patch on set days of the week with progesterone on set days of your cycle, each with its own rules.
I see this in the app every day. Around two-thirds of the women using HRTMe are managing two or more HRT medicines, and the most common set-up is a cyclical or phased routine, where what you take changes through the month.
How the progesterone window drifts
A common instruction for progesterone in sequential HRT is the one in the official product information for Utrogestan capsules: "twelve days in the last half of each therapeutic cycle (beginning on Day 15 of the cycle and ending on Day 26)" (emc). The NHS says sequential combined HRT "is taken in 28-day cycles".
A 28-day cycle is exactly four weeks, so on that instruction day 15 lands on the same day of the week every time. Drift starts when your progesterone runs on a different clock from the rest of your routine. The British Menopause Society's guidance for clinicians says progesterone "can be taken on days 15-26 of the cycle or for practicality it can be taken on days 1-12 of each calendar month." Calendar months are 30 or 31 days long, apart from February, so a window on the 1st to the 12th starts on a different day of the week each month: Thursday 1 October, Sunday 1 November, Tuesday 1 December. Put that next to a patch you change on fixed days of the week and the two slide past each other. That's drift.
Counting from your period
Some women I hear from have been told to start counting again from their period, so when it comes early or late the whole window moves. That isn't the standard NHS instruction, so if that's what you've been told, check it with your prescriber. Where it is the instruction, it's the hardest version to keep track of, because you can't write next month's dates in your diary until your period has arrived.
Counting cycle days is enough work that even an NHS leaflet about switching to continuous HRT lists, as one of the plus points of continuous HRT, that it "avoids having to work out which days of your cycle to take the pill."
Drift, with real dates
Here's what that looks like for a woman in that situation. It's a made-up example to show the drift, and your own prescription and leaflet always come first. Say she changes an oestrogen patch on Mondays and Thursdays, and has been told to take progesterone capsules on days 15 to 26, counting day 1 from the first day of her period. Her periods don't keep to 28 days.
- Cycle 1: her period starts on Thursday 1 October. The capsules run from Thursday 15 October to Monday 26 October, so they start and finish on patch days. This cycle turns out to be 31 days long.
- Cycle 2: her next period starts on Sunday 1 November. The capsules now run from Sunday 15 November to Thursday 26 November, starting on a day when nothing else is due. This cycle is 29 days.
- Cycle 3: her period starts on Monday 30 November. The capsules run from Monday 14 December to Friday 25 December, so her last capsule is on Christmas Day.
On fixed 28-day cycles, the NHS pattern, every window would have run from a Thursday to a Monday, and the December one would have finished on Monday 21 December. Two slightly longer cycles moved it four days later and onto different days of the week, and back in October she had no way of knowing.
If she uses oestrogen gel as well as a patch, or instead of one, that's a dose due every single day, with the moving capsule days on top of it.
Why the drift matters
Drift makes it easy to miscount by a day, and a capsule started a day late rarely feels like a big event. The cost shows up later. Once you aren't sure whether you took something on Sunday, you start wondering whether that's why you slept badly on Monday, and you end up second-guessing the routine when you meant to be judging how the HRT is working for you.
That's why part 3 of this countdown, on whether your HRT is working, starts with checking the doses actually went in. A clear record of what you took makes everything else easier to read.
What helps
The practical side, from reminders to what to do if you miss a dose, is already in the World Menopause Day guide and in what to do if you forget to take your HRT, so I won't repeat it here.
Where HRTMe fits
HRTMe holds each medicine on its own schedule and reminds you on the days each one is actually due, including routines where the medicine changes partway through the month. The app keeps the timetable, so you don't have to carry it in your head.
And if your prescriber moves your progesterone days, you change it once in HRTMe and every reminder moves with it. No re-setting a stack of phone alarms, no telling Alexa all over again, no crossing things out on the calendar.
It's on the App Store.
Next, part 2: aches, pains and this year's World Menopause Day theme, "Chronic Pain At Midlife".
General information only, not medical advice. Always follow your prescriber's instructions and the leaflet for your own HRT.
— Jane