Your saliva crystallizes during your fertile days. Hence women with irregular cycles can also use Babyndex. There is no need for months of body temperature data.
A 2018 study by Harvard Medical School showed that saliva test can predict ovulation with more than 99% accuracy, if complemented with automated crystal detection.
You can use Babyndex as many times as you want. This is environment friendly and you can also save a lot compared to purchasing single-use hormone stripes on the market!