The Diagnosis of Pregnancy

Ordinarily diagnosis of pregnancy presents no problem to patient or physician. In contrast to most conditions for which people seek a doctor, pregnancy is usually prediagnosed by the patient. Yet on rare occasions its diagnosis may be puzzling. The correct answer to such a puzzle is then determined from three types of data: the patient’s symptoms, certain bodily changes found by the physician on his physical examination, and specific laboratory tests.


Absence of Menses

Failure to menstruate (amenorrhea) is usually the earliest evidence of pregnancy. A missed menstrual period in a woman between fifteen and forty-five with previously regular cycles who has been having sexual intercourse suggests pregnancy as the most likely possibility, though not the only one, since there are many other causes for a delayed or even a skipped period.

Age must be taken into account, since the periods may be quite irregular toward the onset and the termination of a woman’s menstrual career. Recent childbirth, especially when a woman is nursing, may obliterate the menses temporarily or lengthen the interval between them. Illnesses, including severe anemia, tuberculosis, untreated diabetes, disturbances of the thyroid gland, high fever from infection, and a host of other diseased states may create menstrual disturbances. Malnutrition may lead to an absence of menstruation; the failure of many female war prisoners in World War II to menstruate during incarceration was probably mainly for this reason. Amenorrhea may occur in women who have lost weight rapidly on a very strict anti-obesity regimen. Psychological factors may be responsible for absence of menses. Among these one may list adjustment to a new country of residence; a change of jobs; a sudden emotional upset, as death of a loved one; war bombing; and either fear of conception or an overpowering mania to become pregnant, as tragically met in women with a long history of sterility.

Abbreviated Menses during Early Pregnancy

Women may be pregnant and still appear to menstruate during the early months. On close observation, such menstrual periods are different. Ordinarily they are shorter and scantier. In the typical instance the woman menstruates three days instead of five at the normal time her period is due. A month later she menstruates half a day, the following month for an hour, and then the menses cease entirely during the remainder of pregnancy. Not infrequently women may develop menstrual cramps at the first missed period without any bleeding or staining. They fully expect to menstruate each hour, but do not. The discomfort lasts for three or four days, then passes off.

Breast Changes

Many women suffer a pronounced fullness of the breasts premenstrually, which subsides rapidly just before or with the onset of menstruation. When pregnancy occurs, this fullness continues instead of disappearing, and becomes even more marked. At the same time the pregnant woman may feel a tingling in the breasts, and they may become tender, the nipples being hypersensitive. These sensations usually are of short duration; the breasts remain large, but the feelings of tenseness and tenderness disappear. In preparation for lactation the mammary glands actually continue to increase in size during the remainder of pregnancy, the enlargement in part being due to growth of the milk-secreting glandular tissue and in part to a greatly enriched blood supply. This latter is often manifested in the second half of pregnancy by the appearance of a delicate tracery of blue veins beneath the skin on the chest, especially noticeable in women with very fair skin. The nipple and the colored circle of skin surrounding it—the areola—enlarge, and their pigmentation, especially in brunettes, darkens. Arranged in a circular fashion around the periphery of the areola, near the skin edge, are a number of small, roundish elevations, oil glands—in the inimitable words of Montgomery, their discoverer, ‘a constellation of miniature nipples scattered over a milky way.’ In some women breast enlargement is accompanied by the formation of stretch marks in the skin—striae; since they appear more extensively over the abdomen they will be discussed later in this article under ‘abdominal changes.’

Nipple Secretion

After the first few months a sticky, yellowish, watery fluid —colostrum—may be expressed from the nipples by gently stripping the breast. This finding is not absolute evidence of pregnancy, for women who have borne and suckled children may retain colostrum in the breasts for years. In the later-months of pregnancy drops of colostrum may flow from the nipples spontaneously. As term is approached, the colostrum takes on an opaque, whitish appearance, more resembling milk.

Nausea and Vomiting

Nausea and vomiting in pregnancy—’morning sickness,’ as they axe so cheerfully termed in popular speech—are going out of fashion. Twenty-five years ago most pregnant women appeared to suffer from morning sickness. This is no longer true; if one eliminates slight cases of occasional, unimportant queasiness, far fewer than half of today’s pregnant women are plagued by it. It is difficult to explain this. Perhaps the improvement is associated with better all-year-round diet, improved health, a higher incidence of planned conceptions, a changed attitude toward pregnancy and labor, or some unlisted factor. The last few decades have witnessed a marvelous revolution in the way the average woman regards childbirth. She was tense, fearful, apprehensive; but now she is relaxed, reassured, and confident. Multiple causes are responsible. The pregnant woman realizes that obstetrics has improved vastly, so that pain, illness, and death for those bringing life are virtually relics of the past. Then, too, she is no longer kept in ignorance about the process of birth.

Morning sickness usually begins when the pregnant woman’s menstrual period is several days overdue, and then gradually disappears six to eight weeks later. In the beginning the patient awakens with a feeling of gastric instability, a little uncertain as to whether she is going to vomit or not. The uncertainty is replaced in a few days by the actuality, which usually occurs as soon as she lifts her head from the pillow. As the morning lengthens, the nausea and vomiting diminish, and by lunchtime she eats an ordinary meal. There are exceptions to this pattern; some women vomit only in the evening, and others at irregular times or all day long. Some are actively nauseated during early pregnancy by odors from the kitchen, and others by tobacco smoke. The temporary abstinence from cigarettes has often advertised a woman’s pregnancy when she was trying hard to conceal it.

It is not uncommon for the woman who vomits during pregnancy to observe that her vomitus is flecked or streaked with blood. This should not cause concern, as repeated vomiting from any source may rupture a tiny blood vessel in the throat or esophagus. Such a small vessel soon clots and heals spontaneously.

Many instances are recorded of particularly suggestible husbands who vomit with their pregnant wives; there are even cases in which the husband vomited though his wife did not.

Excessive salivation to the amount of three or four quarts a day is sometimes a concomitant of pregnancy.

Changes in Appetite

It is not uncommon for the newly pregnant woman to note a temporary diminution in appetite, and ordinary amounts of food make her feel overfull and bloated; without the advice of a physician, she is likely to substitute frequent small feedings for scheduled meals. Some pregnant women develop a craving for one food to the point of mania. If allowed, they will eat the particular food to the exclusion of almost all else. In my own experience I have seen different women crave soup, pretzels, and dill pickles. The wife of a young staff member, who subsisted solely on his anemic salary, selected, of all possible foods, lobster as the object of her craving. Two or three evenings a week the two would trudge downtown, and enviously he would watch her devour a lobster. Previously they had attended an occasional concert or theater, but these pleasures had to be forgone for lobster money.

When one reads the obstetrical texts of a few centuries ago and observes the space and emphasis they gave to what they termed ‘pica’ or aberrations of appetite, one gains the impression that the condition is probably only one-fiftieth as common today as it was then. Unquestionably diets are more diversified and better balanced today, and the opportunity to obtain milk, fruits, and vegetables at all times of the year is greater. It is quite possible that many of these aberrations were yearnings to supply dietary deficiencies.

Excessive Need of Sleep

In some women one of the early symptoms of pregnancy is an overpowering sleepiness. Sleeping late in the morning and napping in the afternoon do not prevent the pregnant young wife from yawning in her husband’s face and from dozing even at her own dinner parties. This excessive need for sleep disappears after the first few months.

Urinary Symptoms

Sometimes frequency of urination begins as early as the first missed period. This condition disappears about the tenth or twelfth week, often to recur a few weeks before delivery.

Abdominal Changes

As pregnancy progresses, the patient becomes conscious of the gradual enlargement of her abdomen. She first notices this about the twelfth week, when a small lump may be felt just above the pelvic bone. This lump, the pregnant uterus, grows upward, reaching the navel at about the twentieth week. The patient begins to ‘show’ at some time between the sixteenth and twentieth weeks, and it is very unlikely that she can keep her secret much beyond this point. As the abdomen increases in size some curious, pinkish streaks appear in about 85 per cent of pregnant women; the streaks are frayed-looking and slightly sunken beneath the surface of the skin. They run longitudinally on the lower abdomen and in a transverse semicircular fashion on the upper abdomen. The stretch marks increase up to term and fade after delivery, though they do not wholly vanish, assuming a shiny, pearl-white appearance. » There are other minor abdominal changes which the woman notices. Brunettes are most likely to develop a dark streak which runs down the center of the abdomen, its continuous course interrupted by the navel. This line pales after delivery, but never completely disappears. The navel itself, which is ordinarily a pit, becomes level with the rest of the abdominal wall and may even protrude, forced outward by increasing intra-abdominal pressure. After delivery the navel’s previous pitlike state is restored. The end of the breastbone, the xiphoid, is attached to the middle of the ribs by a hinged joint. Ordinarily this dagger-shaped bone cannot be felt. However in very late pregnancy the pressure within the upper abdomen may rotate it outward so that a bony bump may be felt in the ‘V’ space between the two sets of ribs. Its presence is normal.


Usually between the sixteenth and twenty-second weeks the patient first experiences ‘quickening’—that is, she first perceives the movements of the fetus. These movements have been poetically compared to the faint fluttering of a bird’s wings against an imprisoning cage. At the onset the motion is so gentle that the patient is uncertain what she feels, usually confusing the activity of the fetus with intestinal gas; she is sure only after the movements have been repeated several times. Later in pregnancy the movements of the child’s arms and legs feel like powerful thrusts from within, and at this stage every woman is convinced she carries a centipede—if not a centipede, at least twins or triplets. These vigorous movements can be seen with the eye; the abdomen bulges momentarily under the impact of the thrust. Usually the movements are noticed earlier by those who have already borne children, for they have learned to interpret the first faint impulses, and in exceptional cases movements may be felt as early as the twelfth week. In the beginning the perception of fetal movements is not continuous, and at first days may pass when they are not felt at all. In later pregnancy, however, they are felt daily, but even then there are hours when they are absent; the supposition is that at this time the fetus is asleep.

All these evidences of pregnancy noticed by the patient— failure to menstruate, breast growth, morning sickness, changes in appetite, excessive need of sleep, urinary frequency, abdominal enlargement, and quickening—can be simulated by other real or imagined conditions. Therefore a positive diagnosis of pregnancy cannot be made solely on the basis of the patient’s observations. The observations of the physician and the laboratory are the only trustworthy means of making the diagnosis.


Virtually every organ and tissue of the body is affected in some measure by the physiologic changes induced by pregnancy. These changes result, directly or indirectly, from the action of the chemicals produced by the afterbirth, the placenta. Considering the fact that the placenta’s primary function is to strain out food essentials from the mother’s bloodstream for the baby and to excrete its waste products, it is amazing that it is also such an energetic and efficient chemical factory.

The most striking pregnancy changes occur in the generative organs. Therefore, in order to diagnose pregnancy, the doctor examines the reproductive organs to determine whether any of the anticipated physiologic alterations have occurred.

Examination of Breasts

He ordinarily begins by examining the breasts. First he inspects them to see if there is any change in size, or in nipple and areola pigmentation. He looks for Montgomery’s glands as well. Then he palpates (explores with the tips of his fingers) the breast to determine if the glandular tissue has begun to spurt in growth. At the same time his trained and sensitive fingers feel for tumors or cysts which should not be there. The last step in his examination is to strip the gland in an attempt to milk colostrum from the nipple. If several of these observations are positive, there is presumptive though not absolute evidence of pregnancy.

Abdominal Examination

Ordinarily a doctor is a very thorough man; his training has made him so. Whenever he performs an abdominal examination he carries it out in a routine manner, no matter what the cause of the examination. First he palpates the liver and gall-bladder regions in the upper right abdomen. He then feels for the spleen in the left upper abdomen. This is followed by an attempt to locate the lower pole of each kidney in either flank. Next he turns his attention to the mid-abdomen, the region beneath and surrounding the navel or umbilicus. Next he examines the lower abdomen to determine whether he can feel a mass in an area which normally would be occupied by an enlarging uterus. At about the tenth or twelfth week the pregnant uterus begins to rise up out of the pelvis, forming at first a small, discrete midline swelling, globular and soft, which the experienced examiner can differentiate from firmer and less rounded tumors, such as fibroids, which may occupy the same area. The palpation of the typical softish mass is also presumptive, but not conclusive, evidence of pregnancy.

At varying periods after the twentieth week the fetal outline can first be discerned by palpating through the full thickness of the abdominal wall plus that of the uterus. The fetus can be felt as a firm, irregular mass within the relatively soft uterus which surrounds it. It is much like feeling a doll through several thicknesses of blanket: the larger the doll, the easier it is to be certain of its outline; the thinner the blanket, the surer the task becomes. On abdominal palpation the head of the fetus feels like an apple and the buttocks—the breech —like a stuffed, slightly irregular cushion. The back feels quite firm and straight, while the hands, feet, arms, and legs are like irregular bumps or knobs. The palpation of such a fetal outline is almost 100 per cent proof of pregnancy, but occasionally it can be so closely simulated by a nodular, intra-abdominal, nonpregnant growth that confusion results.

Pelvic Examination

After completing his examination of the abdomen, the physician examines the vagina and pelvic organs for indications of pregnancy. In preparation for the pelvic examination the patient has been instructed by the nurse to empty her bladder completely before entering the examining room. She is brought down to the edge of the examining-table, legs held wide apart by footrests.

The principal changes in the vagina during pregnancy are threefold: increased blood supply, softening of the tissues, and augmented secretions. The circulatory changes appear rather early in pregnancy, usually before the second missed period, and often serve as a valuable aid for the establishment of the diagnosis. The tissues about the entrance of the vagina and within it take on a purplish, dusky color instead of the normal pink (Chadwick’s sign). The color deepens as pregnancy advances, and is likely to be more striking in those who have already borne children.

As pregnancy advances, the vagina becomes increasingly elastic and distensible because of the softening of the tissues which form its walls. This change facilitates the performance of a vaginal examination.

The increase in vaginal discharge which is usually concomitant with pregnancy is in large part due to the normal excess in activity of the mucus-secreting glands of the cervix.

To perform a pelvic examination the physician inserts the first and second fingers of his gloved hand into the vagina. He first feels for the mouth of the womb, the cervix, which protrudes into the upper vagina like a finger. In the nonpregnant woman it is firm, but it softens considerably under the influence of pregnancy. This softening begins at about the eighth week and increases as pregnancy advances. A week or two earlier, Hegar’s sign may have appeared—it consists of an apparent diminution in thickness of the uppermost portion of the cervix, where it merges with the uterus. This reduction is only apparent; actually there is a localized zone of softening which renders the tissues at this point more compressible.

To conclude the examination the physician maps out the size of the uterus by grasping it between his two fingers in the vagina, pressing upward, while the fingers of the abdominal hand exercise inward, downward pressure on the lower abdomen. This brings the uterus between the examiner’s two hands. Not until the seventh or eighth week after the last menstrual period can growth changes be appreciated—now for the first time the uterus seems a little broader and softer. The increase in size and softness proceeds rapidly, and by the twelfth week the uterus is twice as large as the nonpregnant uterus.

The changes noted on vaginal examination—bluing of the tissues, softening of the cervix, indefinite point of junction between the upper cervix and the body of the uterus, enlargement and softening of the uterus—are only presumptive signs, since conditions other than pregnancy may cause them.