Monitoring Monthly Cycles

When trying to get pregnant, timing is everything. There is a very narrow window during which a woman can get pregnant, so it is important to know when that is.

How a Woman’s Cycle Works in a 28-Day Cycle*

Day 1

The day a woman starts her period.

Day 14

The day a woman may ovulate -- i.e. release an egg.

24 hours

How long the egg is viable after ovulation. This is a woman’s most fertile time.


The day a woman starts her period until the day before she starts her next period.

*Some women may not have a 28-day cycle. 

How To Predict Ovulation

Knowing exactly when a woman ovulates (releases an egg) can help to improve the chances of getting pregnant. It may be on day 14, but it could be a little earlier, a little later, or not at all. If the woman ovulated that month and is not pregnant, it is generally 14 days until the next cycle begins. Thus if a woman is ovulating and has 30 day cycles, then she may be ovulating around day 16 instead of 14.

Some women can tell when ovulation occurs due to changes in the body - twinges in the lower abdomen and/ or a clear, slippery vaginal discharge (from the cervical mucous) are common predictors. There are several tools available to help women determine their most fertile time, such as ovulation predictor kits or basal body thermometers.

Other Timing Facts

In order for pregnancy to occur, sperm must be present during the woman's most fertile time. To ensure that sufficient sperm is available, intercourse is recommended every other day near ovulation, rather than every day. Following intercourse, sperm lives for 72 hours, but the egg should be fertilized within 24 hours. An important point to remember is that just because a woman ovulates on "Day 14" one month, does not mean she will the next.

Having intercourse two to three times per week may improve fertility.

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