A bleed is not proof of ovulation. You can have something that looks and feels like a period without ever having released an egg, which is disorienting to learn after years of assuming a calendar told you everything.
With PCOS this matters more than usual, because irregular or absent ovulation is one of the diagnostic criteria — and because it is the thing most interventions are trying to restore.
Basal body temperature
What it tells you: that ovulation happened, after the fact.
Progesterone, produced only after ovulation, raises your resting temperature by roughly 0.3–0.5 °C. Taken at the same time each morning before you sit up, speak or drink anything, a sustained rise held for three or more days is good evidence an egg was released.
The catch: it is retrospective. It confirms this month rather than predicting this week. It is also sensitive to alcohol, illness, broken sleep and a warm room, which produces a lot of noisy charts.
Best used across two or three cycles to establish whether you ovulate at all, rather than as an ongoing daily obligation.
LH strips
What they tell you: that a surge occurred, roughly 24–36 hours before ovulation.
They predict rather than confirm. A surge does not guarantee an egg was actually released — that gap is real and under-explained on the packaging.
The PCOS problem: many of us run a chronically elevated baseline LH. That produces repeated faint positives, or a test line that never quite goes away, which means very little. If your strips are perpetually almost-positive, that is itself information worth taking to your clinician rather than a reason to keep buying strips.
Day-21 progesterone
What it tells you: definitively, whether ovulation occurred.
A blood test measuring progesterone, which only rises meaningfully after ovulation. This is the most conclusive of the three.
The naming problem: “day 21” assumes a 28-day cycle. The test needs to land roughly seven days before your next period is due. If your cycles run 40 days, day 21 is far too early and will return a low result that gets misread as no ovulation.
If your cycles are irregular, ask for the test to be timed to your cycle, or repeated. This specific misunderstanding causes a lot of unnecessary worry.
Temperature confirms. Strips predict. Progesterone proves. Use at least two.
What to do with the answer
If you are ovulating, irregularly or not, that is genuinely reassuring and changes what to prioritise. If you are not, that is the thing to work on rather than the symptoms downstream of it.
Either way, blood sugar work is the first lever — see the four-step path. Inositol has the best trial evidence for improving ovulation rates specifically, covered in the inositol guide.
Questions people actually ask
How long should I track before concluding anything?
Two to three full cycles. One cycle can be atypical for all sorts of reasons and is not enough to draw a conclusion from.
Do wearable trackers work for this?
Devices measuring skin temperature continuously can detect the post-ovulatory shift reasonably well and remove the daily thermometer discipline. They are still confirming rather than predicting.
Is cervical mucus tracking useful?
Yes, and it is free. Fertile-quality mucus tends to appear in the days before ovulation. With PCOS it can be patchy or appear repeatedly without ovulation following.
What if I am not ovulating at all?
That is worth a proper clinical conversation rather than more self-tracking. It is common with PCOS and it is treatable.
More in the hormone health section.