Background
Various aspects of fertility knowledge, including the timing of the fertile window, have consistently been found to be poor. Limited evidence also suggests ovulation monitoring to time intercourse could be common. However, there have been no studies that compare these two aspects of fertility and women’s fertility/infertility experiences.

Aim
To examine the frequency of ovulation monitoring and its relationship with fertility knowledge and experience.

Method
A cross‐sectional study of women aged 25–50 years resident in southern New Zealand was undertaken in 2011. Randomly selected women were asked to complete a fertility questionnaire. Outcome prevalence measures were calculated with 95% confidence intervals (CI) and associations investigated using χ2 tests and Poisson regression.

Results
Ovulation monitoring was common, having ever been undertaken by 31.4% (95% CI: 28.5–34.3%) of the 1034 participants. However, knowledge was poor, particularly regarding the fertile window. More women who had ever monitored ovulation correctly identified the fertile window, although the proportion was still very low (18.4 vs 13.1% in those who had not, P = 0.027). Regression modelling showed ovulation monitoring was independently associated with seeking medical help to conceive, education and fertility experience, but not with knowledge.

Conclusion
This study confirms ovulation monitoring was commonly undertaken. However, many women, including those who had monitored their ovulation, had poor fertility knowledge and failed to identify the fertile window. Poor fertility knowledge needs to be addressed, especially among women intending to conceive.