What it is
The cervix is the lower neck of the uterus, projecting into the top of the vaginal canal. It has a tiny central opening — the os — usually no wider than a straw outside of labour.
It is not a passive wall. Its secretions change daily under hormonal instruction, and those changes are readable.
Mucus across the cycle
Oestrogen makes mucus wetter and more sperm-friendly; progesterone dries and thickens it.
- Just after your period
- Dry or barely-there.
- Building
- Sticky, then creamy and lotion-like.
- Peak fertility
- Clear, stretchy, egg-white. This is the most fertile signal there is.
- After ovulation
- Abruptly thick, tacky or dry, under progesterone.
Position and firmness
Around ovulation the cervix sits higher, feels softer (often compared to lips rather than the tip of your nose) and the os opens slightly. In the luteal phase it drops, firms and closes.
MenstrualBae uses logged mucus quality alongside temperature and ovulation tests to narrow your fertile window beyond a calendar guess.