Health information

Last updated 21 October 2026

MoonCycle gives general information and estimates to help you understand your own cycle. It is not a medical device, does not diagnose or treat any condition, is not contraception, and does not replace a doctor, nurse or pharmacist.

Predictions are estimates

MoonCycle estimates your next period, your cycle phase and, if you turn them on, your fertile days, from what you log. Cycles naturally vary, and estimates are less reliable when cycles are irregular, in your first months of tracking, and with hormonal contraception, pregnancy, breastfeeding, illness or approaching menopause.

Not contraception

Do not rely on MoonCycle to avoid pregnancy, or to time it. Pregnancy is possible on days before and after a predicted ovulation day. A GP, pharmacist or sexual health clinic can help you choose reliable contraception.

Insight cards and tips

Cards and tips are general information written from public health sources, mainly the NHS, and each card links to its source. They are chosen by what you log, to be relevant, but they are not a diagnosis and not personal medical advice. When a card suggests seeing a GP or getting help, please follow that advice.

Getting help

Emergency: call 999 or go to A&E.
Urgent, not an emergency: call NHS 111 or go to 111.nhs.uk.
Someone to talk to: Samaritans, 116 123, any time.
Anything else that worries you: your GP or pharmacist.

Outside the UK, call your local emergency number.