The cervix sits several inches inside the vagina and separates the vagina from the uterus.
Women check their cervix by inserting a finger and feeling it. There are three things to note: low vs. high, soft vs. hard, and open vs. closed. Low vs high refers to how easy it is to reach the cervix. Throughout the cycle, the cervix moves higher and lower - when it's low it's easier to reach, when it's high it's more difficult. Soft vs hard refers to the firmness of the cervix, which varies from more firm, similar to the firmness of the nose, to soft, similar to the firmness of lips. Open vs closed refers to how large the opening of the cervix is.
The advantage of checking the cervix daily are
- Especially when learning, it helps you discover the range of changes.
- It's another sign to cross-check which is particularly useful when you are having an unusual cycle or are a beginner.
- It's a good way to crosscheck the temperature and cervical fluid observations.
- It can be used to crosscheck cervical fluid observations if temperature is unreliable (fever, travel, etc can make temperature inaccurate).
- It only requires ~7 days of checking a month.
Personally, I'd encourage any young, engaged women out there to give it a try. I found it a bit awkward at first - it was easiest for me to try while lying down, and it's definitely something you'll need to be relaxed to try. After getting the hang of it, it hasn't been very difficult. It's taken a while to figure out what is soft/hard, low/high, open/closed, but after a month I think I've figured it out. It's been really reassuring to have three signs to compare instead of only two.