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This interactive tool estimates your peak fertility period, also known as your "fertile window." This is when you are most likely to get pregnant. Do not use this tool to prevent pregnancy.
In the tool, you will enter the typical length of your menstrual cycle, and you will click on the first day of your last menstrual period.
Fritz MA, Speroff L (2011). Clinical Gynecologic Endocrinology and Infertility, 8th ed., Philadelphia: Lippincott Williams and Wilkins.
Your "fertile window" is up to 6 days long, once a month. It includes:
If you want to become pregnant, try to have sex every day or every other day from your first fertile day to your last fertile day.
If your periods are irregular, this calculator is not a good way to predict your ovulation dates. Do not use this tool to prevent pregnancy.
For more information, see the topics Fertility Awareness, Pregnancy, and Fertility Problems. If you are looking for information on birth control, see the topic Birth Control.
Other Works ConsultedFritz MA, Speroff L (2011). Clinical Gynecologic Endocrinology and Infertility, 8th ed., Philadelphia: Lippincott Williams and Wilkins.
Current as ofSeptember 5, 2018
Author: Healthwise StaffMedical Review: Adam Husney, MD - Family MedicineDonald Sproule, MDCM, CCFP - Family MedicineKathleen Romito, MD - Family MedicineKirtly Jones, MD - Obstetrics and Gynecology, Reproductive Endocrinology
Current as of: September 5, 2018
Author: Healthwise Staff
Medical Review:Adam Husney, MD - Family Medicine & Donald Sproule, MDCM, CCFP - Family Medicine & Kathleen Romito, MD - Family Medicine & Kirtly Jones, MD - Obstetrics and Gynecology, Reproductive Endocrinology
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