As you plan for the care of your baby during the nine months before he is born, you will want to know something of the place where his life begins; where one tiny cell is so miraculously stimulated and nourished that it finally develops into a beautiful little body. Not only will you find all of this of absorbing interest, but a general idea of the structures and workings of those parts of your body where the baby lives and grows will help you better to understand some of the doctor’s precautions and to give yourself intelligent care while your body performs its supreme function.

To begin with, there is the pelvis. This is a very irregular, bottomless, bony basin, or curved canal, within which lie the reproductive or generative organs to be described presently. The pelvis is really composed of four bones which are entirely separate in early life but firmly welded into one rigid structure in adults. I mention this because many women believe that labor pains are caused by a spreading or opening of these bones, whereas, as we shall see presently, the pains are really due to the strong contractions of the muscles of the uterus (or womb) in which the baby lies, which force the baby down through this inflexible ring. You may see in Fig. 1 how the pelvis is placed in the body, being interposed between the spinal column, which it supports, and the thighs upon which it rests. We can feel two of its prominent points on either side below the waist, as our hips, and we rest upon two other projections while in the sitting position.

This bony canal is drawn in, or narrowed about midway in its length so that it is broader above and below than it is in the middle. You are likely to bear the doctors speak of this narrow part as the inlet. I thought you would be interested to know about this for it is largely in order to discover the size and shape of the inlet that the doctor is so anxious to make certain examinations and measurements.

The wide part of the pelvis above the inlet is called the upper, or false pelvis, while the smaller cavity below is known as the true pelvis. During the early part of pregnancy the baby lies in the true pelvis, but as pregnancy advances and he grows larger, he pushes up through the inlet into the larger pelvis where he remains until he is born. When that time comes he must pass down through the inlet again on his way into the world. If this opening is about the usual size and shape and the baby is of an average size, he will usually pass through with comparatively little trouble. But if the inlet is smaller than normal or of an unusual shape, it may be difficult, or even impossible, for the head of a normal-sized baby to pass through without the doctor’s assistance. You can see how important it is, therefore, for the doctor to know beforehand about the size and shape of the pelvic inlet, since it enables him to plan to help with the birth, if necessary, thus saving mother and baby from exhausting themselves in trying to do the impossible. In the old days many mothers and babies were injured, and sometimes even lost their lives, because doctors did not know about measuring the pelvis and planning ahead of time for a difficult labor. But now they know how to make things easier and safer.

It is worth mentioning here that proper care during infancy and childhood, with proper food, fresh air and exercise, helps to promote normal development of the pelves of little girls, and this in turn tends to make childbirth normal for these children when they grow up and are ready to have babies of their own.

The Generative or Reproductive Organs. The pelvis is an interesting structure but not nearly so interesting as the generative organs which lie within it: the uterus (or womb), tubes and ovaries. These, with the vagina, are often called the internal genitalia because they are inside the body. The pelvis practically remains rigid and inactive throughout pregnancy and labor, but the ovaries and the uterus are constantly active and are concerned with an undertaking which is so utterly amazing that it is far beyond our powers of understanding. We can only look on and wonder.

The uterus, or womb, in which the baby develops, is a firm little mass of muscle, which, in its non-pregnant state, is much the shape of a slightly flattened pear, about three inches high, an inch and a quarter wide at its broadest point, three quarters of an inch thick, and weighs about two ounces. We usually speak of the main part of the uterus as the body: the round top as the fundus and the smaller part of the organ, below, as the neck or cervix. This important little organ is placed about the middle of the true pelvis, with the upper end pointing slightly forward. (See Fig. 2.) It is more or less swung in this position by being attached to ligaments instead of to any fixed part, the ligaments, in turn being attached to the sides of the pelvis. This explains why the uterus may move about, tip forward or backward, and how, by a stretching of the ligaments that hold it, it is able to grow and push upwards as pregnancy advances.

Within the body of the uterus is a flat cavity which is somewhat triangular in shape, with an opening at each of the three corners. The two upper openings lead into the tubes, which will be described in a moment, while a third opening leads down into the cervix, the lower end of the cervix, in turn, protruding into the vagina. The upper and lower ends of the cervix are drawn in as though with a draw string so that they are scarcely more than small round holes. These are called the internal os and the external os. Fig. 3 gives an idea of how the cavity of the uterus and the cervix would look from the front, with the tubes reaching out from the upper corners of the uterus, and the cervix opening into the vagina. The uterus is lined with a soft mucous lining something like the lining of one’s mouth. Bear this in mind, for this lining represents, in part, the soil in which the tiny human seed is planted and through which its roots draw nourishment.

The Fallopian tubes are two little muscular passage ways, about five inches long, which extend from the two upper corners of the uterine cavity toward the sides of the pelvis. The tubes are very small where they arise from the uterus, but gradually grow larger toward their free ends and finally spread out into wide, funnel-shaped openings that lead directly into the abdominal cavity. The tubes, also, are lined with a mucous membrane but of a most surprising kind. Its surface is covered with tiny hair-like projections which make it something like a brush with very soft, moist bristles. These little hairs are in constant motion, waving and sweeping along in much the same way that a field of wheat waves and sweeps in the wind. Remember about this, too, for it has something to do with the very beginning of the baby.

The Ovaries. Very near and a little below the flaring, open ends of the tubes are the ovaries, the sex glands of the female. There is one on each side, held in place by ligaments and they are about the size and shape of almonds. In the ovaries are embedded the ova, or eggs, the female germ cells which are concerned with producing the baby and also with the function of menstruation.

Just a word about what is meant by “a cell.” It is simply a tiny mass of jelly-like substance, called protoplasm, contained in a thin membrane or skin and is so small that it can be seen only through a microscope. In its unmatured state the ovum is a single cell, about ¹⁄₁₂₅ of an inch in diameter. In the protoplasm there is a spot called the nucleus and within this a smaller one called the nucleolus, or the germinal spot. These are long names and you need not remember them unless you want to, but glance at Fig. 4 which shows an ovum and you will see that in its general structure it is much like a hen’s egg, for the latter has a yolk within the white and on the yolk a tiny speck or germinal spot. The formation of each woman’s full quota of ova, fifty thousand or more, is probably complete at the time of her birth.

The vagina is a muscular tube, or passage way, leading from the outside of the body to the cervix, which you will remember is the lower part of the uterus. The vagina slopes upward from its opening and instead of meeting the cervix evenly it meets it almost at right angles and encases it like a sheath for about half an inch. Fig. 2 shows how these organs would appear if we were looking at them from the side.

The Bladder. If you will glance again at Fig. 2, you will see that just in front of the vagina there is a tiny passage leading up to a sac which also is in front of the vagina, and since in this picture it is practically empty, it lies below the uterus. This sac is the bladder and you can readily understand that as the uterus enlarges during pregnancy, it presses upon the bladder and this pressure on the outside gives the same sensation as is produced by pressure from the inside when the bladder is filled with urine. That is why the expectant mother has such a constant desire to urinate during the early weeks of pregnancy, before the uterus pushes up into the abdomen, and also during the later weeks, as well as during labor, when the bladder is being pressed upon by the baby’s head.

The Rectum. In the same picture you will see the rectum which lies just behind the uterus and vagina and which terminates in the anus. Between the rectum and the vagina is a thick triangular mass of muscle, called the perineum, which practically forms a floor to the pelvis, the bony basin without a bottom.

The external genitalia, sometimes called the vulva, really have nothing to do with the creation of the baby, but you will better understand some of the care that is given you if you know a little about them, too. Between the thighs, where they join the body, are two thick folds of flesh, called the labia and between these lie the perineum, just mentioned, and the openings from the rectum, vagina and bladder as shown in Fig. 2.

Now that we have something of an idea of the structure of the organs concerned with the creation of the baby, we shall want to learn about the usual activities of these interesting little parts, before the baby begins his life within them.

Puberty or Adolescence. You know, of course, that girls are incapable of becoming mothers until after what is termed puberty, or adolescence, and by these terms we mean the period during which childhood develops into sexual maturity, and the individual becomes capable of reproduction. The age at which puberty occurs varies with climate, race and occupation and with different individuals of the same status. But the average for girls, in temperate climates, is from the twelfth to the sixteenth year and for boys from the fourteenth to the seventeenth year. Girls in southern climates sometimes mature as early as the eighth or ninth year while in colder regions puberty may be delayed until they are eighteen or twenty years old.

The occurrence of puberty marks the establishment of ovulation and menstruation, two functions which are usually performed once a month during the childbearing period.

Ovulation, which probably occurs about midway between the menstrual periods, is simply the name which has been given to the principal function of the ovary and may be defined as the development of the ovum, or egg, and its expulsion, when mature, from the ovary. As the entire human body has its origin in this tiny ovum, its career and course of development are of momentous importance to us, and at the same time furnish a tale of absorbing interest. The ovaries are packed full of these tiny egg-like cells, which probably lie dormant, as stated before, until the girl reaches puberty. Then they begin to develop and grow and push their way from the inside of the ovary to the surface where they look more or less like blisters. When an ovum reaches the surface of the ovary, a thin membrane which contains it, bursts, and it is suddenly expelled into the abdominal cavity. You will remember that the ovary is very near the funnel-like end of the tube, so, when the little cell is shot out of the ovary, it finds itself floating around quite close to this wide opening. Some of the ova that are projected into the abdominal cavity are doubtless lost, but others find their way into the near-by mouth of the tube, and if not fertilized by uniting with a male cell, which we shall explain presently, they pass down the tube into the uterus and are finally carried out in the menstrual flow. It is probable that as a rule only one ovum ripens and escapes from the ovary each month from puberty until the menopause or change of life.

The interesting thing about all of this is that each time an ovum does mature and is discharged from the ovary, the lining of the uterus becomes thicker and softer in order to facilitate the attachment of the ovum, if it is fertilized, this attachment being necessary if a baby is to develop. This preparation of the uterine lining is often, and very appropriately, referred to as “nest-building.”

Menstruation, which is the evidence of sexual maturity, is a monthly hemorrhage from the uterus, escaping through the vagina, and it normally recurs regularly throughout the childbearing period, except during pregnancy and while the young mother nurses her baby. The length of this childbearing period is about thirty years and continues from puberty until the menopause. The frequency of the menstrual periods varies from twenty-one to thirty days but the normal interval between periods is twenty-eight days, which is the length of what is called the “menstrual cycle.” Thus it is usually a lunar month from the beginning of one period to the next one, making thirteen menstrual periods during each calendar year. The complete course of a menstrual cycle consists of four stages, which, it is believed, occur somewhat as follows:

The first, or constructive stage, lasts about seven days. It is during this stage that the preparations are made to receive the ovum traveling down the tube. The entire uterus becomes congested with blood and is somewhat enlarged and softened as a result, while its lining grows red, thick and velvety. If the ovum remains unfertilized, which is usually the case, it does not attach itself to this elaborately prepared lining, but passes out with the uterine discharges and all of this preparation not only goes for naught but must be undone.

The second stage, therefore, which lasts about five days, is the destructive stage and is the period we speak of as menstruation. During this period the extra tissue which has been formed in the uterus is broken down; it mixes with the blood that oozes from the congested lining and together they pour from the vagina as the menstrual flow.

The third or reparative stage, which follows, occupies about three days during which time the uterus and its lining return to their normal state.

The fourth, or quiescent stage, now follows and lasts twelve or fourteen days. This is the time remaining before Nature, with unwearying patience, begins all over again to prepare for the reception and attachment of the next matured ovum, in ease of its possible fertilization. And so it goes, month after month and year after year.

It is very important for a woman who is suffering from painful menstruation to consult a doctor about correcting the cause, in the interests of her future childbearing, if for no other reason, for this is one step toward preparing a good soil in which to plant the seed from which a baby may grow. For example, a misplacement of the uterus is a frequent cause of painful menstruation and if it remains uncorrected may make conception impossible; or if conception perchance does take place, the malposition of the uterus may, later, be the cause of an abortion or miscarriage. Inflammation of the lining of the uterus is another cause of menstrual difficulty and if allowed to persist, may interfere later on with the normal development and nourishment of the baby.

The menopause, also termed the climacteric, or the change of life, marks the permanent stopping of menstruation and ability to bear children. This ordinarily occurs between the ages of forty and fifty, the majority of women ceasing to menstruate during their forty-sixth year.

The most favorable age for motherhood to begin is a subject of considerable interest to most women. When it is considered from all standpoints, social, ethical, spiritual as well as physical, the most favorable age for motherhood to begin seems to be sometime in the early twenties. Children have been born to little girls nine years old and to women over sixty, but the extremes of the reproductive years are not favorable periods for childbearing.

Now a word about the breasts. They appear to be merely large, soft masses of fat, one on each side of the chest, having no connection with the pelvic organs. But in reality they are very complicated glands and strangely enough, though no one knows why, their activities are controlled by the activities of the generative organs down in the pelvis. Certain it is that their function is very important to the baby, for the breasts are the factories in which nourishment is produced to nourish him during the first few months after he is born.

If we could look inside of the breasts we should see that in structure they are much like several clusters of grapes in which the stems and grapes are hollow. The milk is formed in the tiny sacs corresponding to the grapes, and pours into the little tubes conforming to the stems; these empty into a central tube, opening upon the surface of the nipple from which the baby will extract his nourishment. If you will look at Fig. 5 you will see in that picture of the front of a breast, that a part of it apparently has been magnified to show these openings of the milk ducts. There are about fifteen or twenty of them in each nipple. The picture shows also the little glands which appear as small lumps under the skin around the nipple, both in the dark circle called the areola and in the white skin surrounding it.

Summing up this chapter briefly, we find that the pelvis is an irregular, bony canal or basin, drawn in about the middle, thus forming the upper, or false pelvis and lower or true pelvis, neither of which has a bottom. The opening between these two basins is called the inlet, while the lower margin of the true pelvis is called the outlet, but it is the inlet that is of particular importance during childbirth. In the center of the lower pelvis and swung upon ligaments attached to its sides is the uterus, whose lower part, called the cervix, extends downward into the vagina; while reaching out from the upper corners of the uterus are the tubes, and near their open ends, one on each side, are the ovaries filled with germ cells called ova. The bladder lies in front of the uterus and vagina and the rectum behind, while below is the perineum, forming a floor to the pelvic cavity. Every four weeks during the childbearing years an ovum is expelled from one of the ovaries into the abdominal cavity and the uterus regularly prepares to receive it in case of its fertilization, but if it is not fertilized the ovum is lost and menstruation occurs.

We see, too, that although the breasts are situated remotely from the pelvic organs they are really very important accessories, since they provide milk to nourish the baby after his life within the uterus is terminated by his birth.