Theory of The Safe Days
 

The operation of the menstrual cycle is a phenomenon JL with which scarcely one woman in ten is thoroughly familiar, although it is a regular function of their daily lives. An understanding of it may aid those couples who, due to faulty timing, fail to bring about impregnation, or contrariwise, find it desirable to reduce it.

It is interesting to notice that as recently as approximately twenty years ago the details of the phenomenon of the menstrual flow were not completely understood by the medical profession. We may avoid a description of all the lengthy, patient, scientific research which went into the study and concentrate on what is generally accepted.

It is known that the female egg or ovum ripens in an ovary cavity known as the Graafian follicle. When the egg matures fully, fifteen days preceding menstruation, the follicle bursts, allowing the egg to enter the Fallopian tube. This process is known as "ovulation." The egg must be fertilized by the male sperm within a few hours after ovulation; otherwise the egg perishes. Since the precise moment of ovulation cannot be determined, twenty-four hours are allowed for fertilization, although it occurs in less time, perhaps in the neighborhood of four. The male sperm can maintain its fertilizing vigor at best for only two days after entering the female body, but it can live considerably longer.

It is known also that the pituitary gland, located in the brain, does, among other functions, create activity of the uterus. The day following ovulation, a group of cells called the "yellow body" comes into being on the ovary, nullifies the control of the pituitary over the uterus, and instructs it to relax and adjust itself to the arrival of the egg by taking on increased supplies of blood.

Finally, in order to develop normally, the fertilized ovum must imbed itself in the wall of the uterus. This can be accomplished only when the uterus is quiet and the membrane relaxed.

Now that we understand the basic facts, let us see how pregnancy takes place, or how, failing impregnation, a menstrual flow occurs.

Ovulation takes place fifteen days before a period and the egg starts a journey through the Fallopian tube. It must be speedily fertilized or it dies. The day following ovulation, the yellow body materializes on the ovary and starts to exert its influence over the uterus by commanding quiet and directing nourishing stores of blood to it.

Unfortunately for women, the yellow body automatically issues its instructions to the uterus on the assumption that a fertilized egg will arrive there. However, should the ovum perish by reason of nonfertilization, the yellow body realizes this only ten days later, and then starts to deteriorate. By the fourteenth day, it has disappeared, whereupon the pituitary, once again in control, induces contractions in the uterus, causing it to dislodge a lining consisting of excess blood and mucus. The female thus experiences the beginning of the menstrual flow.

If, however, a fertilized ovum arrives at the uterus and successfully attaches itself, the yellow body reacts differently and retains control until the beginning of labor, when the pituitary again takes command, causing the contractions of the womb which expel the child.
 

These principles make it obvious that a woman can conceive only within twenty-four hours or less following the ovulation which occurs on the fifteenth day prior to menstruation. This day, then, is not "safe." Furthermore, since the spermatozoa can remain vigorous for forty-eight hours, it is apparent that intercourse occurring one or two days prior to ovulation is "dangerous" because the sperm, still alive and potent, may be waiting for the egg at time of ovulation. Thus, the seventeenth and sixteenth days before menstruation are likewise "unsafe."

Consequently, conception appears theoretically to be possible only from relationships occurring on the seventeenth, sixteenth, or fifteenth day prior to ovulation; all other days in the cycle should be "safe." If a woman has a cycle of twenty-six days and a menstrual period of five days, she has eighteen days during which she can feel free from impregnation. That is the basis of the theory of the rhythm. However, there are complications to be considered.

First of all, this theory applies only to a woman with a constant twenty-six-day cycle, who knows beyond doubt that she is precisely that regular. Suppose, however, that she ovulates two days sooner or later; no medical man will deny this possibility. If she ovulates two days earlier than usual or seventeen days before her period instead of fifteen, she is susceptible to impregnation by intercourse occurring on the nineteenth, eighteenth, or seventeenth day before her period. Failing this, her flow will start two days earlier. If, on the other hand, she ovulates two days later than usual, or on the thirteenth day prior to the normal date of her period, then intercourse on the fifteenth, fourteenth, or thirteenth day subjects her to the possibility of pregnancy. Barring this, her period will fall two days late.

It must be borne in mind that a woman has only her past regularity to depend upon, and that no one can state positively that this regularity will continue. The fact is, it will not. Nor is it possible to determine the exact date of ovulation except by consulting a record of previous periods, since it can be established only by going back fifteen days from the last day of the cycle.

It seems obvious that if we add two days to each side of the original three dangerous days, increasing them now to the nineteenth, eighteenth, seventeenth, sixteenth, fifteenth, fourteenth, and thirteenth we have made an allowance for any future irregularity of the ovulation date. This is advisable under any circumstances and advocates of the rhythm themselves suggest it.

However, although we have allowed for an irregularity of two days in either direction, no one can guarantee against the future possibility of a three, four, or five-day irregularity. This unexpectedly happens to many women, and the discrepancy can obtain for as long a period as a week or more. To be reasonably safe, we may add four days on each side of the original three danger days as a more than sufficient allowance for a system which is presumed to operate with far greater scientific consistency. The questionable days now represent the twenty-first, twentieth, nineteenth, eighteenth, seventeenth, sixteenth, fifteenth, fourteenth, thirteenth, twelfth, and eleventh days before the usual termination of the next period. Now, in a theretofore regular cycle of twenty-six days, five days of which include menstruation, with eleven days questionable, a woman can feel reasonably safe for ten days.

Although this allowance of an extra four days is considerably more than that regarded as necessary by one of the research scientists principally responsible for this enlightening discovery, it still may not be enough. Nature is far too unreliable, and many unexpected happenings may occur to alter a previously regular menstrual cycle: a fall, a blow, a shock, an illness, a psychological explosion, an accident, a change of climate or overstimulation. If a shock can bring about an abortion or miscarriage, it is not inconceivable that it may cause a contraction of the ovary and force the Graafian follicle to expel an egg prematurely.

On the other hand, an egg may precociously mature far ahead of its time. Since the Graafian cavities and their contents have been developed since adolescence and perhaps at birth, it is not impossible for an individual egg to mature weeks in advance or a retarded one, weeks later.

Furthermore, the authorities advise that before applying this principle, the regularity of the menstrual cycle be carefully recorded and observed for at least a year, and for an additional four or five months following any subsequent disruption, in order to determine whether it occurs with absolute consistency. Obviously, they also recognize the possibility of occasional irregularity.

In addition, it is perfectly possible that nature, which is known to play unexpected pranks, may decide to release eggs from both ovaries at different intervals during the same cycle instead of the customary single egg. In fact, fraternal twins have been born whose relationship was that of half-brothers. Each had a different father. Nor can anyone say how frequently a pair of eggs are released at different intervals, because a relationship may not have taken place at the time one or the other was expelled.

A girl who marries at twenty has roughly twenty-five years before the menopause. Calculated at the rate of twelve cycles a year, although there will be more, she undergoes in that span three hundred cycles which we may further reduce by eighteen while she bears two children. It is not farfetched to assume that out of the remaining two hundred and eighty-two cycles, nature may deviate at least half a dozen times. If pregnancy ensues as the result of only three of the six occasions, the family has been unexpectedly increased.

While it is absolutely true that many people operate under the rhythm principle to their satisfaction, others have failed to find it reliable. It may be argued, of course, that the latter were careless in their application, but they deny it.

There is also some difference of opinion among the authorities themselves; some state that ovulation definitely takes place only on the fifteenth day preceding the end of the next period, while others assert that it may occur on any one of five consecutive days. Although both sides have ample evidence to support their contentions, the layman is unable to resolve the conflict.

The figures used are based on a woman with a simple twenty-six day cycle. Some women, however, experience a double cycle, such as twenty-six days one month, and twenty-eight days the next. Still others are subject to a triple cycle of twenty-six, twenty-eight, and thirty days over a period of three months. While it is not difficult to work out a table to meet these situations, since only the extremes are considered, it requires too much calculation, the results of which still offer questionable security. This is, of course, a matter of opinion.

However, one reliable and valuable fact exists, if the present explanation of the menstrual cycle is accepted. A specific period encouraging impregnation has been determined. And it can be utilized or avoided depending upon the desire for a family.

It is appropriate to discuss briefly at this point the practicability of engaging in intercourse during a men-trial period. Beyond the inconvenience of it, there is no healthful reason why it shouldn't be practiced. It will neither lengthen nor decrease the flow as many women believe.

Furthermore, a great proportion of females acquire their strongest sexual urges at this time. Since the first and last day of the period are usually characterized by a slight staining only, a relationship, then, is not too disagreeable. However, should a wife indicate any reluctance to engage on these occasions, no husband should insist upon it.

This must not be construed to mean that a wife has no duty or responsibility during this period to satisfy her husband's sexual needs. Many women flow the better part of a week, and this is a long interval for a man to practice self control. A thoughtful and devoted mate will not ignore her husband's sexual moods at this time. On the contrary, she will take pains to anticipate and satisfy them, if need be, by adequate means at her disposal.
Should she be one of those women whose periods are attended by pain and discomfort, naturally, no obligation exists. But barring this, any indifference to her husband's feeling is inexcusable. Considerations of this type on the part of both partners provide the kind of home atmosphere that cements marriage ties and encourages general compatibility.