Fertility

Fertile times?

Originally Published: February 04, 1994 ~ Last Updated / Reviewed on: July 14, 1998

 

Alice,

When can a woman, during her menstrual cycle, be at high risk for pregnancy? I've heard two answers: fourteen days before or after your period. Which is it?

--Conceiving only ideas

 

Dear Conceiving only ideas,

The simple answer to your question is that the egg bursts from the ovary (ovulation) approximately two weeks before the beginning of your next menstrual period. A common misunderstanding is that the egg bursts from the ovary at midcycle, halfway between menstrual periods. This is only true when the cycle is twenty-eight days long (something that cannot be known for certain until that particular cycle is over and menstruation begins).

A woman can become pregnant from unprotected intercourse up to five days before ovulation. Sperm can survive in a woman's body for three to five days, waiting to fertilize that egg during ovulation. Therefore, guessing how long your period usually is and counting backward fourteen days is not an effective method of birth control.

The fertility awareness method of birth control (a studied, standardized monthly procedure), however, can be quite effective if used diligently and properly. Being aware of your fertile times involves counting days, observing cervical mucus, taking your body temperature with a basal thermometer (see below for details) daily, and charting your own observations. This method also requires a highly motivated person. For more information, contact the Fertility Awareness Network at P.O. Box 1190, New York, NY 10009.

Fertility awareness can be quite effective when taught carefully, understood thoroughly, and used correctly. The major disadvantages are the risk of pregnancy if you are not committed to using it correctly; it does not protect you from sexually transmitted diseases (STDs), including HIV infection; it takes at least two or three cycles to learn and use confidently; it can be sexually frustrating if you choose to abstain from intercourse rather than use a barrier method when you are fertile; and, most importantly, it may be impractical if you are not in a committed, cooperative relationship with your sexual partner.

Alice

P.S.: Basal body temperature is the temperature of the body when you first wake up. This needs to be measured using a basal thermometer [a basal thermometer is a special thermometer used to track ovulation that measures temperature in tenths of a degree, like the standard oral thermometer, but its numbers are magnified to make it easier for you to read your basal body temperature more clearly] immediately after waking in the morning to be most accurate. Women need to have a basal thermometer ready by the bed because any movement (even getting up from bed to get the thermometer) can cause the temperature to fluctuate.

Basal body temperature needs to be measured and recorded every day for several months; after a rise and a plateau, there will be a sharp drop in temperature followed by menstruation, which would indicate that the woman is ovulating

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