A score (out of 12) for the quality of cervical mucus, gauged by scoring each of the following from 0 to 3: the cervix should be open and the volume of mucus should be good (although every woman will be different for both these parameters, they will be consistent in one woman from ovulation to ovulation); the mucus should be clear, watery and stretchy (Spinnbarkheit); and the mucus should produce a complete 'ferning' pattern when it's allowed to dry on a microscope slide. The first two criteria vary at ovulation in different women (so anything above a score of 9 or 10 can be normal), but the same woman should achieve the same Insler score from one ovulation to the next. Also called the Insler score.

In our context, the frequent estimation of serum estradiol (or perhaps estimating the cervical score) and performance of transvaginal ultrasound to estimate how close a woman is to ovulation.

The frequent estimation of serum estradiol (or perhaps estimating the cervical score) and performance of transvaginal ultrasound to estimate how close a woman is to ovulation.