Dear meow_mix17,

Not likely. The first part of a woman's fertility cycle — from the first day of her period to the release of an egg from her ovary — differs in length from woman to woman and, often, from cycle to cycle. The first part can last from seven to 20 days, or more.

The second part of a woman's cycle — from the release of the egg to the day before her next period begins — is pretty much the same for all women. It lasts from 14 to 16 days.

But the trick is knowing exactly when all these events take place. Much easier said than done!

With so many variables, it is difficult for most women to predict which days are safe for unprotected intercourse. Young women have very irregular cycles. And most women's cycles are not always exactly the same length, no matter how mature they are. Also, illness, stress, and physical exercise can change the length of a woman's cycle.

Many women chart their fertility patterns to know what days are safe and what days are unsafe for unprotected intercourse. But these methods work best for older women in long-term relationships with only one partner who is cooperative and committed to using these methods. Couples also need to be trained for several months by a professional in order to use most of these methods.

A woman has a good chance of becoming pregnant from unprotected vaginal intercourse during the six days that end in ovulation. She is less likely to become pregnant from unprotected intercourse in the day or two following ovulation, but it is possible. Ovulation usually occurs about 14-16 days before the start of a woman's menstrual cycle. But because most women's cycles vary from month to month it's very important to use birth control every time you have sex.

Hope this information helps!

Take care,

teenwire.com^® Editors

This column is for informational purposes only and is not intended to constitute medical advice, diagnosis, or treatment. If you have a medical problem, please call toll-free 1-800-230-PLAN for an appointment with the Planned Parenthood health center nearest you.