If you and your husband wish to postpone pregnancy, you have several contraceptive options available. The Natural Family Planning (NFP) approach has many advantages, yet it receives little attention in popular media or the medical community. What’s the reason for this lack of awareness? Often it’s the common but mistaken impression that any method of postponing pregnancy that doesn’t involve medical technology is unreliable or even haphazard. However, studies indicate when couples are taught to use NFP consistently, this method is as effective as oral contraceptives and easily surpasses the effectiveness of condoms, which have a failure rate that is widely considered to be as high as 10 to 15 percent per year. In addition, natural family planning poses no moral or ethical dilemmas for those concerned about the use of other contraceptive technologies.
Basic Principles of NFP
All forms of NFP involve identifying a woman’s “fertile” days, then abstaining from sexual intercourse on those days if postponing pregnancy is the goal, or engaging in intercourse if a baby is desired. The original calendar or “rhythm” method (devised in the ’30s) was based on the knowledge that the time between ovulation (when the ovary releases an egg) and the beginning of menstruation is nearly always two weeks. Women with regular menstrual cycles are most successful with this method since they can predict the timing of their next period, then count back two weeks to determine their fertile days. Unfortunately, at least 25 percent of women don’t experience cycles with clockwork regularity, and even those who do might have an unexpected change caused by stress, illness, or other factors.
More recent NFP methods can better pinpoint a woman’s fertile period. In 1964, Australian neurologist John Billings and his wife, Lyn, a pediatrician, described a method of predicting fertility that involves a daily self-check of cervical mucus. When a woman nears ovulation, her mucus becomes increasingly clear, watery, and elastic, like an egg white. Before and after these fertile days, the mucus is thicker, stickier, and virtually impenetrable—an effective barrier to sperm.
A key time in the cycle is the arrival of the “peak day,” after which the mucus begins to revert to its former thick, sticky condition or disappears altogether. The peak day correlates with ovulation. Couples who want to postpone pregnancy avoid intercourse when the mucus becomes thin and clear, and abstain for three days after the peak day. Even though an unfertilized egg lives only 12 to 24 hours, ovulation can take place two or even three days after the peak day. Abstinence is also necessary for a few days prior to the peak day because sperm can survive for two to three days in the cervix when the mucus starts to thin. Here’s an easy rhyme from an organization that teaches the Billings method to help you remember it: When mucus is wet, a baby you may get. When mucus is dry, the sperm will die.
Another NFP approach based on the Billings method is the sympto-thermal method. Couples not only assess cervical mucus but also a woman’s basal body temperature, which consistently rises about a half degree when ovulation occurs. A woman takes her temperature with a special thermometer every morning before getting out of bed and marks the results on a basal body temperature chart, making it possible to see when ovulation has taken place.
Couples using this method also note other symptoms to help them identify ovulation, including mid-cycle ovarian pain with ovulation, vulvar swelling, or abdominal bloating. None of these symptoms are reliable alone, but they can help confirm if your estimate of fertile days is accurate.
Advantages of NFP
With NFP, no drugs, devices, or procedures are involved—thus, there are no side effects or medical risks such as future infertility. Here are some other benefits:
Cost is minimal. Aside from the initial cost of NFP materials or books and the price of a basal body thermometer, there are no ongoing expenses.
NFP can enhance partnership in marriage. Because both you and your husband must share responsibility in order for these techniques to work, communication in marriage (especially regarding sex) usually improves.
NFP methods are also useful to couples who want to become pregnant. When intercourse is accurately timed to ovulation, the odds of conceiving increase.If you and your husband have had difficulty becoming pregnant, your knowledge of your menstrual cycle, basal body temperature, and cervical mucus is useful if a medical evaluation for infertility becomes necessary.
Drawbacks of NFP
Natural family planning requires consistency and ongoing self-discipline to succeed. If your husband won’t cooperate, or if he resents the abstinence required each month, other methods may be more appropriate. Here are other factors to ponder:
It takes a while to become comfortable with this method. Until you have a long, reliable track record with NFP, it isn’t advisable if you must not become pregnant for medical reasons.
This method may not work well in certain situations. These include if you have abnormal mucus production, a very small temperature rise with ovulation, or certain medical problems (such as polycystic ovaries) in which your hormonal patterns are abnormal or extremely unpredictable.
As you and your spouse prayerfully consider the method of birth control you feel most comfortable using, make sure you fully understand how any method works to prevent pregnancy and the possible impact each could have on your body and hormones. This is not a decision to be taken lightly or without proper research on the various methods available.
Paul Reisser, M.D., is a family physician in Southern California who serves on the Family’s Physicians Resource Council for Focus on the Family. Dr. Reisser and his wife, Teri, have two adult children.