Following release of the egg from the ovary (ovulation), the human egg
is capable of fertilization for only 12 to 24 hours. You are most likely to
become pregnant if you have sex on the day of ovulation. However, live
sperm may still be present in your reproductive tract on the day of
if you had sex for up to five days before ovulation.
download a Fertility Chart to print OR as an Excel file at
to help you track your BBT and cervical mucus
If you are using anovulation prediction kit, start testing 3 days
before the expected date of ovulation. If
you have irregular cycles, use the length of your shortest cycle in the
past six months to estimate when to start testing
Keep in mind that even if a woman's cycles are usually regular thetiming
of the fertile window can be highly unpredictable, occurring
during a broad range of days in the menstrual cycle. Couples wishing to have a baby can
avoid the uncertainty of predicting fertile days by engaging in
intercourse two or three times a week
1. Allen J Wilcox, David Dunson, and Donna Day Baird. The timing of the "fertile window" in the menstrual cycle: day specific estimates from a prospective study
BMJ 2000; 321: 1259-1262.PUBMED 11082086
2. Wilcox AJ, Weinberg CR, Baird DD.Timing of sexual intercourse in relation to ovulation. Effects on the probability of conception, survival of the pregnancy, and sex of the baby.
N Engl J Med. 1995 Dec 7;333(23):1517-21.PUBMED 7477165
All calculations must be confirmed before use. The suggested results are not a substitute for clinical
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