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Trying to conceive: Timing is everything

Many couples have misconceptions about conception. They expect to get pregnant as soon as they start trying. However, when you take a look at what’s involved in the process of conception, you can begin to appreciate that it’s not something to be taken for granted.

Each month, a woman produces one egg that’s capable of undergoing fertilization for about 12 hours. A man supplies about 100 million sperm with each ejaculation, but most sperm don’t make it very far on their journey toward the egg. In fact, fewer than 200 are likely to reach the fallopian tube, where conception can occur. Those sperm are capable of fertilizing an egg for 24 to 72 hours.

That’s why timing is so important. In fact, two common causes of fertility problems are simply not having intercourse at the right time in your menstrual cycle and/or not having intercourse often enough.

Generally, couples who want to conceive should have intercourse within 24 to 72 hours of the moment the egg is released from the ovary. Because sperm live longer than eggs, it’s considered better to have intercourse immediately prior to ovulation than afterward.

How can you tell when you’re ovulating? If you have a regular 28-day menstrual cycle, it’s likely that you ovulate on or close to the 14th day of your cycle (day one is the first day of your period). A more accurate way to predict ovulation is to track your basal body temperature (BBT) every morning before getting out of bed and record it on a graph. Basal body temperature is the lowest temperature reached by a healthy person during waking hours. Most women have a slight rise in basal body temperature after ovulation. Because this change occurs after you ovulate, you won’t be able to detect a pattern that enables you to predict ovulation until you’ve tracked your BBT for several months. Even then, you may have to rely on other physical signs to help you, such as changes in cervical mucus.

The quantity and consistency of a woman’s normal cervical mucus changes during her cycle. For most of the menstrual cycle, this mucus is thick and scarce. You may not notice it at all. As you near ovulation, the mucus thins and becomes more obvious. For most women, ovulation usually occurs about 24 hours after the last day of abundant, slippery discharge. (The slippery mucus may make it easier for sperm to travel through the cervix.) Once you become attuned to these changes, you can use them to time intercourse. An advantage of tracking changes in cervical mucus is that mucus changes appear in a recognizable pattern even among women whose menstrual cycles are otherwise irregular.

Over-the-counter ovulation predictors are another option. They work by detecting a surge in luteinizing hormone, or LH, which occurs just prior to ovulation.

Assuming there is no underlying cause of infertility, using any of the methods described here can help you to conceive.