Ovulation: the signs, the tracking methods, and which are worth the money

The free signs

Cervical mucus is the most useful and costs nothing. After a period it is dry or sticky; as ovulation approaches it becomes wetter, clearer and stretchy — like raw egg white — and that slippery stage is the most fertile. Afterwards it turns thick and sticky again.

Basal body temperature: taken with a digital thermometer at the same time every morning before getting out of bed, it rises by around 0.3-0.5°C after ovulation and stays up until the period. It confirms ovulation has happened rather than predicting it, so it is useful for learning your pattern over a few months.

Other signs: a one-sided twinge or ache mid-cycle (mittelschmerz), slight breast tenderness, a small rise in libido, and a softer, higher, more open cervix. Some women notice light spotting around ovulation, which is usually harmless.

Kits, monitors and apps

Ovulation predictor kits detect the surge in luteinising hormone that precedes ovulation by 24-36 hours — genuinely useful for timing, particularly with irregular cycles. Test in the late morning or afternoon rather than first thing, and read exactly as instructed: a faint line is a negative.

They can mislead with PCOS, where LH may be persistently high, and they show a surge without confirming that an egg was actually released.

Apps predict from your past cycles. That is a calendar with a nice interface — it cannot know that this cycle is different. Use one to record data (period dates, mucus, temperature, test results), not to be told when you are fertile.

Wearable and saliva-based monitors are expensive and add little over mucus plus a kit. Blood progesterone testing about a week before the expected period, ordered by a doctor, is the reliable confirmation that ovulation occurred.

When ovulation is not happening

Signs that ovulation may be absent or irregular: cycles shorter than 21 days or longer than 35, cycles that vary by more than about a week, no periods for three months or more, no temperature rise across several months of accurate charting, and no fertile-type mucus at any point.

Common causes: PCOS (the most frequent), thyroid disease, high prolactin, very low or very high body weight, extreme exercise, chronic stress, and approaching menopause.

Most of these are treatable. Ovulation induction with tablets is a straightforward, inexpensive first-line treatment, and many women conceive on it. The point of tracking is not to keep charting for years — it is to notice quickly that something needs a doctor.

When to see a doctor

Book an appointment for: cycles under 21 or over 35 days, cycles varying widely, no periods for three months, no evidence of ovulation over several tracked cycles, or a year of trying without conceiving (six months if 35 or over).

Same-day: severe one-sided pelvic pain, particularly with fever, faintness or a missed period, which needs assessment for ovarian torsion, a cyst accident or ectopic pregnancy.

This article is general information, not medical advice, and is no substitute for personal medical advice. For any decision about your or your child's health, please consult your doctor.

Frequently asked questions