Spotting in perimenopause: what's hormonal and what needs a look

Why perimenopause causes spotting

In an ovulatory cycle, progesterone stabilises the uterine lining and its withdrawal triggers one organised bleed. In the anovulatory cycles of perimenopause there is no progesterone phase: estrogen keeps building the lining until parts of it shed on their own schedule — spotting, or an eventual heavier bleed. Hormonal contraception and newly started hormone therapy also commonly cause spotting in their first months, which is expected and worth confirming with the prescriber rather than assuming.

Patterns that need assessment

Most spotting is benign, but clinicians take these patterns seriously precisely because the ones that are not benign are most treatable when found early:

• Any bleeding after 12 consecutive months without a period — always assess, without exception
• Bleeding after sex, more than once
• Between-period bleeding that recurs across several cycles rather than one odd month
• Spotting with pelvic pain, unusual discharge, or after a missed cervical screening
• Heavy bleeding — soaking protection hourly — which is a different symptom with its own urgency

What an assessment involves

Usually straightforward: a history (a dated log of bleeding is the single most useful thing you can bring), a pelvic exam with up-to-date cervical screening, often a transvaginal ultrasound to measure the lining, and sometimes a small tissue sample. Common findings are benign — polyps, fibroids, hormonal shedding — and the point of checking is to be in the large group for whom that is confirmed.

When to see someone

Promptly for any red-flag pattern above. Otherwise, mention recurring spotting at your next appointment and track it meanwhile. If you are unsure which side of the line your pattern falls on, that uncertainty is itself the reason to ask — this is the one symptom where the guidance is consistently 'check rather than watch'.