1. Your cycle may change from month to month.
The length of a normal menstrual cycle varies from 28 to about 36 days. These variations are based on a number of factors, including your natural body rhythms, stress levels, and weight gain or loss. Ironically, the stress of trying to conceive may throw your cycles off kilter. Monitoring your cycle through ovulation predictor kits (OPKs), charting basal body temperature (BBT), and/or examining cervical mucus can greatly increase your odds of becoming pregnant during a particular cycle.
2. All cycles are not created equal.
Even if you menstruate every 28 days without fail (and few women do), there's no guarantee that you'll ovulate exactly midway through your cycle. In fact, women with 28-day cycles may ovulate anywhere from day 12 to day 16 -- or, occasionally, not at all.
3. You're only fertile for 12 to 24 hours.
Once you ovulate, there's a small window of opportunity -- roughly 12 to 24 hours -- before the egg degenerates and is reabsorbed into your body. Fertilization must occur within this period. Yet sperm, which live for two to three days, can take eight hours or more to swim up the cervix and rendezvous with the waiting egg. (Like men, they're not always punctual!) Or the sperm can be waiting for the egg when it comes down. Monitoring your cycle helps you predict when you're going to ovulate at least 24 to 36 hours in advance, giving you more time to get the sperm started on their journey.
4. You may have a short luteal phase.
The second half of your menstrual cycle -- between the day you ovulate and your next period -- is called the luteal phase. Although the normal length of this phase is 12 to 16 days, for some women it is much shorter. If your luteal phase is shorter than this, you will need drug therapy to increase it before you can successfully get pregnant.
5. Cervical mucus may help -- or hinder.
Cervical mucus (the vaginal discharge that accompanies ovulation) varies in consistency and appearance, from thick and cloudy to clear and elastic. In order to provide a fertile environment for the sperm, mucus should have the consistency of egg whites: clear, slippery, and slightly stretchy. It's important to monitor your cervical mucus around the time you ovulate and plan intercourse accordingly.
Sources: American College of Obstetricians and Gynecologists, www.acog.org; American Society of Reproductive Medicine, www.asrm.org
Reviewed 11/02 by Elizabeth Stein, CNM
All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor inconnection with any questions or issues you may have regarding your own health or the health of others.