Cycle tracker adapted for PCOS / PMOS

Why PMOS needs a specialised cycle tracker

Mainstream cycle tracking apps — Clue, Flo, Ovia, Natural Cycles — are designed for regular 21-35 day cycles. They predict ovulation at day 14 (for a 28-day cycle), display a 5-day fertility window, and project the next period with precision. For women with PMOS, this modelling rarely applies: cycles typically last between 35 and 90 days, ovulation is unpredictable or absent (anovulation), and periods may be absent for several months, then unusually heavy when they do arrive.

A cycle tracker adapted to PMOS does not predict — it observes. It records what actually happens, without extrapolation. This observation is valuable at three levels: it objectifies the average cycle length over 6 months (a key diagnostic datum), it detects changes under treatment (pill, progestogen, inositol, metformin), and it helps identify personal patterns that can guide therapeutic decisions.

For women trying to conceive: cycle tracking alone is insufficient in PMOS. Combine it with urinary LH ovulation tests and, if possible, ultrasound monitoring — ovulation may occur unpredictably, and a 45-day cycle does not mean ovulation was at day 22. ACOG and NICE guidelines both recommend monitoring confirmation of ovulation for fertility management in PCOS/PMOS.

What to record and why

A PMOS cycle tracker goes beyond recording period start dates. Here is what to collect and its clinical utility:

• Period start date: defines day 1 of the cycle. Essential for calculating cycle length and scheduling hormonal tests (FSH, LH on day 3; progesterone 7 days before expected period).
• Duration of bleeding: normal = 3 to 7 days. Beyond 7 days, mention it to your doctor.
• Bleeding intensity: light (1 pad/day) to very heavy (>5 pads/day). Menorrhagia (very heavy periods) is common in long anovulatory cycles — the endometrium thickens in the absence of ovulation and natural progesterone.
• Intermenstrual bleeding: spotting between cycles — note it as it can indicate hormonal imbalance or endometrial pathology to investigate.
• Pain: intensity, location (pelvic, lower back, diffuse), and timing relative to the period.
• Associated signs: breast tenderness, bloating, mood, energy level — these data cross-referenced with the cycle help identify hormonal patterns.

Using your cycle tracking data

After 3 to 6 recorded cycles, you can calculate your average cycle length and its variability. These two data points are key for your consultation:

• Average length > 35 days or < 21 days: oligo or polymenorrhoea — one of the diagnostic criteria for PMOS.
• Variability > 10 days between cycles: irregular cycles — also suggestive of PMOS.
• No period for > 3 months (not pregnant, not on hormonal contraception): amenorrhoea — investigate promptly (risk of endometrial hyperplasia from chronic anovulation without progesterone).

Bring your tracking data to every appointment. If you also use the symptom tracker, cross-reference the two: you will see how your symptoms vary with cycle phases — even in an irregular PMOS cycle, patterns exist.

Limitations of cycle tracking

Cycle tracking does not reliably predict ovulation in PMOS. Anovulation can occur even in a seemingly normal-length cycle. If you are trying to conceive, do not base your attempts solely on calculated dates — combine with LH testing and medical monitoring.

Cycle tracking does not detect gynaecological pathologies. Irregular periods can have multiple causes: PMOS, but also hypothyroidism, hyperprolactinaemia, hypothalamic amenorrhoea, polyps, fibroids. Tracking identifies the anomalies; diagnosing their cause is the doctor's role.

Frequently asked questions

My periods have been absent for 6 months — should I be worried?

Yes. Amenorrhoea lasting more than 3 months (not pregnant, not on hormonal contraception) warrants a medical consultation. With chronic anovulation, the endometrium can thicken without being "shed" by periods, increasing the risk of endometrial hyperplasia. A progestogen treatment (to be defined with your doctor) is often indicated to induce withdrawal bleeding and protect the endometrium. NICE guidelines (NG88) recommend investigation after 3 months of amenorrhoea.

Why are my periods so heavy?

In long anovulatory cycles, the endometrium thickens progressively without natural progesterone. When periods finally arrive, they can be particularly heavy — sometimes with clots — because the endometrium is thicker than usual. This is not dangerous in itself, but very heavy periods (>7 days, needing to change every hour) should be reported to your doctor, as they may indicate endometrial hyperplasia needing treatment.

When should I be concerned about spotting between periods?

Light mid-cycle spotting can be normal (notably around ovulation). However, repeated, heavy, or painful intermenstrual bleeding warrants a consultation to rule out endometrial pathology (polyp, fibroid), cervical issue, or infection. Don't ignore it if it persists beyond 2 cycles.

What is the difference between an anovulatory and ovulatory cycle?

An ovulatory cycle includes egg production, an LH surge, and corpus luteum formation that produces progesterone. Progesterone triggers the period and "prepares" the endometrium. In an anovulatory cycle, this sequence doesn't happen — periods can still occur (due to falling oestrogen) but without the protective progesterone effect. The distinction matters for fertility and endometrial protection.

How do I track my cycle while on the combined oral contraceptive pill?

On the pill, "periods" are withdrawal bleeds — not true ovulatory cycles. You can record dates and intensity of these withdrawal bleeds, but they don't reflect your natural cycle. Cycle tracking regains full relevance after stopping the pill — the first weeks and months post-pill can be unpredictable, especially with underlying PMOS.

What is normal post-pill cycle recovery?

After stopping the pill, cycles can take 1 to 6 months to resume — sometimes longer with PMOS. A post-pill amenorrhoea of 2 to 4 months is not unusual. If 6 months after stopping the pill cycles remain absent or very irregular, book an appointment. Post-pill recovery is an opportunity to reassess your underlying hormonal pattern without the masking effect of contraception.