What does perimenopause look like?
The NIA calls the time leading up to menopause the menopausal transition, or perimenopause. Periods may become shorter, longer, lighter, heavier or further apart, and hot flashes, sleep problems and mood changes often begin here.[1]
ACOG explains that cycle length and bleeding often change in your 40s, but lists patterns that are not normal: bleeding or spotting between periods or after sex, heavy bleeding, and bleeding that is heavier or lasts more days than usual.[2]
Why does contraception still matter?
Because ovulation can still happen, the NIA advises continuing birth control for at least a full year after the last period if you do not want to become pregnant.[1]
The Zepbound® and Mounjaro® labels state that tirzepatide may reduce the effect of oral hormonal contraceptives because it slows stomach emptying, most after the first dose. For those first four weeks, and for four weeks after every step up, they point to a contraceptive that is not swallowed or to a barrier such as a condom alongside the pill.[3][4]
The Wegovy® and Ozempic® labels say to stop semaglutide at least 2 months before a planned pregnancy.[5][6]
What do the labels and studies say for this stage?
| What is known | Why it matters | What to log in PepLabo |
|---|---|---|
| Tirzepatide: pill may be less reliable for 4 weeks after starting and after each dose increase.[3][4] | Pregnancy is still possible in perimenopause.[1] | Dose increases and a note when you use a backup method. |
| Semaglutide: stop at least 2 months before a planned pregnancy.[5][6] | Late pregnancy plans need early timing. | Stop and restart dates in the dose history. |
| A post hoc SURMOUNT analysis grouped women by stage; weight fell more with tirzepatide than placebo in each group. Exploratory only.[7] | Shows the trials included perimenopausal women; it does not compare stages. | Weight trend and waist notes over months. |
What does PepLabo not do?
PepLabo is a log. It does not diagnose, measure hormones or body composition, suggest a dose or tell you when to change one.
Period dates, flow and spotting go in the note of a side-effect check-in; there is no separate cycle tracker.
Wegovy® and Ozempic® are registered trademarks of Novo Nordisk A/S; Zepbound® and Mounjaro® are registered trademarks of Eli Lilly and Company. They are named only to identify the medicines and their labels. PepLabo has no affiliation with these companies.
