Can apps and calendar methods predict ovulation with accuracy?

CONCLUSIONS: Ovulation day varies considerably for any given menstrual cycle length, thus it is not possible for calendar/app methods that use cycle-length information alone to accurately predict the day of ovulation.
PMID: 29749274 [PubMed - as supplied by publisher]

Source: Current Medical Research and Opinion - May 12, 2018 Category: Research Tags: Curr Med Res Opin Source Type: research