Can menstrual cycle measurements aid in achieving or preventing pregnancy?

Outside of general health, many people measure the menstrual cycle with the goal of achieving or preventing a pregnancy. This requires detecting the time of ovulation because the likelihood of pregnancy is highest when sexual intercourse occurs during the period from 2 days before to the day of ovulation.^[1] In people with a normal menstrual cycle, there are several simple, inexpensive ways to potentially predict the time of ovulation. These include menstrual cycle charting, oral basal body temperature monitoring, and assessing cervical mucus changes, although the reliability of these methods is questionable.^[2]

There are more accurate ways to detect ovulation. Commercially available tests determine the time of ovulation by measuring the levels of luteinizing hormone and/or estrogen metabolites in a urine sample or by carefully monitoring body temperature, either under the arm or in the vagina, with special devices.^[3] People with an irregular menstrual cycle or difficulty getting pregnant may require more extensive testing to determine when and if ovulation is occurring, such as bloodwork and imaging studies (e.g., ultrasound). It is important to work with an experienced clinician for any menstruation or fertility issues.