…A woman's fertile period depends on the life span of sperm as much as it does on the life span of her egg. The egg lives for about a day. A man's sperm can live inside a woman's body for about five days—possibly seven. Fertilization of a woman's egg is more likely from intercourse before or during ovulation than from intercourse following ovulation. It usually occurs during a six-day period that ends in ovulation.
In total, a woman has a good chance of becoming pregnant from unprotected vaginal intercourse over the course of about nine days of her menstrual cycle—as long as seven days before the release of an egg (ovulation), the day of ovulation, and, possibly, the day after ovulation. She is less likely to become pregnant from unprotected intercourse in the day or two following ovulation, but it is possible.
Understanding her monthly fertility pattern can help a woman avoid an unintended pregnancy. It can also help her plan a pregnancy. The key is for her to know when fertilization may occur by estimating the time of ovulation as nearly as possible. This must be done carefully because the timing of ovulation varies greatly from one woman to another and, for some women, from one month to the next.
Women who monitor their fertility to prevent pregnancy may choose to abstain from vaginal intercourse for at least one-third of each menstrual cycle or to use barrier methods or withdrawal during that time. Periodic abstinence and fertility awareness methods are the two methods of contraception that depend on charting your fertility pattern.
Couples who want to prevent pregnancy using periodic abstinence do not have vaginal intercourse during their "unsafe days"—the days during which the fertile phase may occur. Although they abstain from vaginal intercourse during the fertile days, they may enjoy other forms of sex play.
Couples who use fertility awareness methods (FAMs) use withdrawal or barrier contraceptives—condoms, vaginal pouches, diaphragms, or cervical caps—during their fertile or "unsafe days."
Understanding Your
Menstrual Cycle
Understanding your menstrual cycle is essential for your good health. It is especially important if you want to chart your fertility pattern as a method of contraception.
The monthly pattern that occurs regularly in most women, from puberty to menopause, is called the menstrual cycle. Every cycle is divided into two parts 3/4before ovulation and after ovulation. In a 28-day cycle, the pattern usually follows this timing:
- The beginning of the cycle, called Day 1, is the day bleeding begins. The flow usually lasts about three to five days. Usually by Day 7, certain hormones cause some of the eggs in the ovaries to start ripening. Between Days 7 and 11, the lining of the uterus begins to thicken. The influence of additional hormones after Day 11 causes the egg that is most ripe to be released on about Day 14 in women who have a 28-day cycle. The other ripening eggs stop growing and dry up. That's part one.
- In the second part, the egg travels down the fallopian tube toward the uterus. If a single male sperm unites with the egg while it is in the tube, the fertilized egg may attach to the spongy lining of the uterus. Pregnancy begins if this "implantation" occurs. If fertilization doesn't take place, the egg cell wil break apart in a day or two. About Day 25, hormone levels drop. This causes the lining of the uterus to break down and in a few days it is shed in a menstrual period. Another cycle has begun.
For some women, cycles recur fairly regularly every 28 days. But the number of days in each cycle can vary from woman to woman, from every 21 to every 35 days. In fact, a few women have only three or four cycles a year.
The first part of the cycle, from menstruation to ovulation, may vary from 13 to 20 days in length. The length of the first part is not only different from one woman to another, but also differs in some women from month to month. It is during this critical first part of the cycle that fertilization can occur. Such common circumstances as sickness, worry, physical exertion, and even sudden changes in climate may occasionally upset a regular pattern by shortening it or extending it.
The second part of the cycle, from ovulation to menstruation, is about the same length in all women. The egg is released consistently 14 to 16 days before the onset of menstruation, regardless of the length of a woman's menstrual cycle.
There are a few women who believe they can tell when the egg has been released from the ovary. Some report having a slight pain in the back, or on the right or left side of the lower abdomen. A few may also have some increased vaginal discharge—a little blood-tinged or clear discharge from the vagina. But it is generally accepted that none of these is a sure signal that an egg has been released—the same symptoms can be caused by other factors.
Ways to Chart
Your Fertility Pattern
Here are brief descriptions of the changes you can chart to predict when you ovulate in order to plan or prevent pregnancy. More complete descriptions follow.
- For the temperature method: Take your temperature every morning before getting out of bed. Your temperature rises between 0.4?F and 0.8?F on the day of ovulation. It remains at that level until your next period.
- For the cervical mucus method: Observe the changes in your cervical mucus. You must do so all through the first part of your menstrual cycle, until you are sure you have ovulated. Normally cloudy, tacky mucus will become clear and slippery in the few days before ovulation. It also will stretch between the fingers. When this happens you are in your most fertile phase. You must abstain from vaginal intercourse or use a barrier contraceptive during this time.
- For the calendar method: Chart your menstrual cycles on a calendar. You may be able to predict ovulation if your periods are the same every month. You must abstain or use a barrier method during your "unsafe days." It will be more difficult to predict the day of ovulation if the length of your cycle varies from month to month. In that case, you will have more "unsafe days." It is best not to rely on this method alone.
It is best to combine the temperature method, the cervical mucus method, and the calendar method. The combination of these methods is called the symptothermal method. (For a copy of Fertility Pattern Chart, click here and print.)
Temperature
Method
One of the changes that ordinarily take place in a woman's body as part of her menstrual pattern is that her body temperature is lower during the first part of the cycle. In most women it usually rises slightly with ovulation and remains up during the second part until just before her next period. Recording each day's temperature helps to indicate when ovulation has occurred.
The temperature method requires charting your basal body temperature (BBT), the temperature your body registers when you're completely at rest. BBT varies slightly from person to person. For most women, 96 to 98 degrees taken orally is considered normal before ovulation and 97 to 99 after. The changes are small fractions—from 1/10
to 1/2 degree. So it's best to get a special, large-scale, easy-to-read thermometer that registers only from 96 to 100 degrees. A rectal or oral basal temperature thermometer can be bought in most drug stores for about $10. Generally, rectal readings are more reliable. But whichever you choose, take your temperature the same way every day.
Taking Your Temperature
Each morning take your temperature, as soon as you wake up—before getting out of bed, talking, eating, drinking, having sex, or smoking. Either insert the thermometer in your rectum or place it in your mouth for a full five minutes. Read the temperature to within 1/10 of a degree and record the reading.
Charting Your Temperature Pattern
Each reading must be recorded. Charts for this purpose may be obtained from your clinician or women's health center. As each day's temperature is plotted on the graph, you will learn to recognize your own pattern. Your temperature rise may be sudden, gradual, or in steps. The pattern may vary from cycle to cycle.
You must also realize that your BBT can be influenced by physical or emotional upsets or even lack of sleep. In addition, illness, emotional distress, jet lag, disturbed sleep, smoking, drinking an unaccustomed amount of alcohol the night before, and using an electric blanket may affect your body temperature. Noting such events on the chart helps to interpret the readings.
In the beginning, you should get help in reading your BBT chart from a physician, nurse, or family planning specialist. In time, under supervision, you'll gain the knowledge and confidence to use the chart by yourself. Be sure to chart your temperature for at least three months before relying on this method.
The Safe Times
After the temperature rise has lasted for at least three days, you can assume that your safe days have begun. They will last until the temperature drop that usually comes just before the onset of your next menstrual period. For complete protection, consider unsafe all the days between the start of your period and the start of the fourth day of the next temperature rise. That is because the temperature method is quite accurate in detecting when ovulation has occurred, but can't predict when it's about to happen. And there's another important reason why the whole first part of the cycle must be considered unsafe—the lifetime of a man's sperm.
Sperm generally remain capable of fertilizing an egg for two to three days after ejaculation. There are even instances of sperm remaining active five or more days after intercourse. So if you have sexual intercourse several days before ovulation, there's a good chance that live sperm could still fertilize a newly released egg. Combining BBT with another method may help in trying to calculate ovulation in advance.
When you become confident about using your BBT to determine your safe days, you may not need to take your temperature between the start of the infertile time and the beginning of your next menstrual period.
Cervical
Mucus Method
The cervical mucus method is based on another change that occurs during the menstrual cycle. The hormones that control menstrual cycle phases also act on the glands of the cervix that produce mucus secretions. The mucus secreted by the cervix collects in the cervix and vagina. It changes in quality and quantity just before and during ovulation. With proper personal instruction, many women can learn to recognize the changing characteristics. Instruction in the cervical mucus method is usually given on a one-to-one basis. The cervical mucus method is also known as the ovulation method or the Billings method.
The Mucus Pattern
- The cycle begins with menstruation. During vaginal bleeding, the flow disguises the mucus signs.
- The menstrual period is usually followed by a few days when no mucus is present —these are "dry days."
- As an egg starts to ripen, mucus increases in the vagina and appears at the vaginal opening. It is generally yellow or white, and it is cloudy and sticky.
- The greatest amount of cervical mucus usually occurs immediately before ovulation during the "wet days." The mucus takes on a clear and slippery quality that resembles raw egg whites. When the mucus can be stretched between the fingers, it is called spinnbarkeit—German for stretchable. This is the peak period of fertility.
- About four days after the wet days begin, mucus may abruptly become cloudy and sticky, reduce sharply in volume, and a few dry days may return before your period starts.
-
Charting Your Mucus Pattern
As with the other methods, records need to be kept. It's suggested that a woman chart her observation daily on a calendar. Mark the days of your menstrual period, the dry days, sticky days, and wet days. It's best for a woman to avoid intercourse for at least one whole cycle when you start to use the mucus method for birth control. Get someone with experience to help you become familiar with your own pattern until you are able to interpret the changes yourself.
A woman can check her mucus in several ways, depending on which is most comfortable for her. She can :
- wipe the vaginal opening with toilet tissue before urination
- observe the discharge on underpants
- obtain some of the mucus by placing her fingers (making sure they are clean) in the vagina.
She should check several times a day when there is any sign of mucus.
This method is less reliable for women who produce little mucus or if the natural mucus pattern is altered by:
- using douches, "feminine hygiene" products, or contraceptive foams, creams, jellies, or suppositories
- surgery that is performed on the cervix—especially if cryotherapy or a loop electrosurgical excision procedure is used
- vaginitis
- sexually transmitted infections
- breastfeeding
- perimenopause
- recent use of hormonal contraceptives.
Women who ovulate on Day 7 or 8 may produce too little mucus to use this method.
The Safe Times
- It is considered unsafe to have vaginal intercourse during menstruation, especially during shorter cycles. Vaginal bleeding can disguise the mucus signs. Non-menstrual vaginal bleeding around the time of ovulation may be mistaken for a menstrual period.
- Intercourse may take place during the brief period of safe dry days that may follow menstruation in a long cycle.
- The fertile phase begins at the first sign of wetness after menstruation, but it may also begin a day or two before wetness begins. Intercourse must be avoided on any wet day, unless you are trying for a pregnancy—fertilization is most likely to occur during this phase. Otherwise, you must refrain from sex for at least three days after ovulation or until the wet days end, whichever is the longer number of days.
- It is considered safe to have sex after ovulation when mucus sharply decreases in volume and becomes cloudy and sticky again. It is considered even safer to have intercourse during the dry days that may follow before your period begins.
Fewer pregnancies occur when intercourse takes place only on the dry days following ovulation.
The Calendar
Method
The calendar method attempts to predict ovulation using a woman's menstrual history. A written record is kept—an ordinary calendar can be used to note each cycle, counting from the first day of one menstrual period up to, but not including, the first day of the next. The day bleeding starts is Day 1, and you mark this by circling that date on the calendar. Continue to circle Day 1 for at least 8 months (12 is better). Then you count the days in each cycle.
Of course, you have no assurance that your cycle variations will remain the same. So you must continue to circle each Day 1 and list the length of your last cycle.
The Role of the Calendar Method
These rules can only help you to find out a couple of days in advance when you probably will ovulate. Calendar records should always be used with other methods explained in this booklet. Always be guided by any sign that says you may be fertile. The calendar method is especially chancy if your cycles are not always the same length.
Charting Your Pattern
Keep a record of the number of days in each cycle. When bleeding starts, circle the date on your calendar.
To find the first day you are likely to be fertile, check your record of previous months, find the shortest cycle, and subtract 18 from the total number of days. For example, if the shortest cycle is 26 days long, subtract 18 from 26, which leaves 8. Starting with the date you circled (the first day of your current cycle) count ahead eight days and draw an X through that second date. That's the first day you're likely to be fertile and, therefore, the first day of abstinence or contraceptive use. But if your temperature chart shows even a slight shift before that, don't have unprotected intercourse until three full days after your temperature rise.
To find the last day you must abstain or use contraception with the calendar method, subtract 11 days from your longest cycle. Draw an X through that date also. Remember, you need to chart your cycles for at least eight months before you can calculate your safe times. Be sure to confirm this with other methods.
The Safe Times
Safer times are likely from the first day of menstruation, Day 1, which you have circled, to the first X. They are also likely from the second X to the next circle. Unsafe days appear between the two X's.
Remember: if all your cycles are shorter than 27 days, don't try to use calendar estimates at all. The first part of any cycle may be irregular. Trying to add a few days of intercourse in the early part of your cycle can be risky when attempting to prevent an unplanned pregnancy. Learning the meaning of changes in your normal vaginal discharge may reduce miscalculations. But always be guided by any sign that says you may be fertile.
Using These
Methods Together
Using all three methods: temperature, cervical mucus, and calendar, is called the symptothermal method. The symptothermal method allows a woman to be more accurate in predicting her safe days than if she uses any one of the methods alone. When using these methods together, the signs of one can serve to confirm those of the other. For example, a record of the mucus pattern can be useful because temperature rises resulting from illness or emotional stress may be confusing. Combining methods also permits sexual relations during the early dry days, and shortens the period of abstinence necessary for complete protection when using the temperature method alone.
In the post-ovulation method, couples abstain from vaginal intercourse or use withdrawal or a barrier method from the beginning of the woman's period until the morning of the fourth day after her predicted ovulation. A woman is much less likely to be fertile after ovulation has occurred (post-ovulation). However, couples who practice the post-ovulation method must abstain from vaginal intercourse or use withdrawal or a barrier method for more than half of the woman's menstrual cycle.
How Well These Methods Work
Of 100 couples who use any of these methods for one year, 20 women will become pregnant with typical use. The failure rate is higher for single women. Combining the various methods with careful and consistent use and having no unprotected vaginal intercourse during the fertile phase can give better results.
Of 100 couples who use the temperature method for one year with perfect use, two women will become pregnant.
Of 100 couples who use the cervical mucus method for one year with perfect use, three women will become pregnant.
Of 100 couples who use the calendar method for one year with perfect use, nine women will become pregnant.
Few couples, however, are able to use these methods perfectly. These methods require keeping consistent and accurate records. Some skill is required in figuring, and the margin for error depends on how accurately signs and records are interpreted and followed. It is most important that original explanations, early coaching, and frequent follow-up be done by a professional instructor or successful users. These methods work better for women whose cycles are always the same length.
Some couples chart the woman's fertility pattern to prevent pregnancy because it is economical, safe, and can be discontinued easily when pregnancy is desired. Little equipment is needed, and calendars, thermometers, and charts are widely available. No medication is involved, which is especially appealing to women who have physical or health conditions that might make other forms of birth control less desirable or unsuitable. Medical checkups are not required, although professional instruction is important. Periodic abstinence is acceptable to most religious groups. However, if a couple decides to have vaginal intercourse during the fertile period, pregnancy is likely to occur unless they use barrier methods such as a combination of condom and foam.
Charting fertility patterns requires dedication, education, and practice. It is most effective when both partners are mature, responsible, and committed to making them work. That's why it is very important for both partners to learn the fundamentals and support each other in observing the abstinence or contraceptive use that is required.
Women who are breastfeeding or approaching menopause may find it more difficult to chart their fertility. Their fertile signs may vary in unpredictable ways due to irregular hormonal fluctuations. Likewise, multiorgasmic women are also likely to ovulate unpredictably.
If you are taking the Pill or any other hormonal method, you'll have to stop taking it and use another method of contraception that has no hormones, such as a barrier method (condoms, diaphragm, cervical cap), while learning fertility awareness methods. Hormones in the Pill alter the natural menstruation and fertility cycle.
Do not depend on charting your fertility pattern if:
- you have irregular periods
- your partner is unwilling to observe periods of abstinence from vaginal intercourse, practice withdrawal, or use barrier methods at unsafe times
- you have a sexually transmitted infection or frequent abnormal discharges
- you cannot keep careful records.
Products for Use with These Methods
At this time no device exists that can simplify or ensure greater success with any of these methods. From time to time announcements are made of patented items to help in calendar calculation or to test mucus change by chemically treated paper, or of other products under development for this purpose. None has proven any more reliable for contraceptive purposes. Success in the use of any of these methods for predicting fertility is the result of good initial instruction, persistence, accuracy in keeping records, and cooperation by both partners in the discipline involved.
Test kits that attempt to predict ovulation are available for home use. They may be useful for planning pregnancies but are not reliable for purposes of birth control. Sperm can live in the fallopian tubes for about up to seven days. So, pregnancy often results from unprotected vaginal intercourse during the six days before ovulation.
Charting your fertility pattern can work for you if:
- You have received careful instruction in the methods.
- You have only one sex partner and he is equally committed to the methods you want to use.
- You have the self-discipline required to check and chart your fertility signs and observe the rules.
- You don't mind abstaining or using withdrawal or barrier methods for the first part of the cycle.
(For a copy of Fertility Pattern Chart, click here and print.)
Charting your fertility pattern may not be appropriate for you if:
- You have more than one sex partner.
- Your sex partner isn't equally committed to the methods you want to use.
- You are temperamentally unsuited for keeping close track of your fertile days.
- You have doubts about being able to abstain from vaginal intercourse for at least 10 days each month or to use a barrier method on "unsafe" days.
- You wouldn't consider having an abortion although you have a medical condition that poses a grave danger for you if you become pregnant.
- You take medication that may affect your cervical mucus, body temperature, or menstrual regularity.
Cost
Charts for graphing fertility signs cost little or nothing. They are available at family planning clinics and from private instructors and organizations. Basal body temperature thermometers cost about $10 to $12. You may have to pay a fee for classes to learn fertility awareness techniques. In some states, Medicaid will cover the cost of classes taken at a clinic or when authorized by a private physician.
Finding a teacher
Couples can learn how the woman's body signs serve as the basis of their contraceptive method by taking a course or being counseled by a health professional trained to teach methods to monitor fertility. Both partners should attend the sessions so each will be aware of precisely how these methods work. Not only will learning the methods together increase their effectiveness, but many couples report that cooperating on contraception helps them become more intimate.
Classes on charting fertility patterns for contraception are offered by many family planning health centers, church-affiliated instructors, and at Catholic hospitals, often at little or no cost.
