The liver is enlarged, but functionally it is less competent, and constipation is common.
It is probable that most of the changes enumerated above are due to the circulation through the body of some definite product of fœtal activity, which is more or less toxic in character. The more pronounced effects of this toxin will be studied under the abnormal conditions of pregnancy.
Generally, if the pregnancy is normal, the whole body responds to the stimulating influence. After the nausea and vomiting of the early months subside, the woman feels energetic and ambitious. She is eager to do something at all times and feels fatigue but slightly. Music, literature or housework engages her attention and is zealously and joyfully practiced. The world seems bright and the thought of her labor does not bring solicitude, but pleasant anticipations. The body fills out in all directions and the woman takes on the appearance of maturity.
DIAGNOSIS OF PREGNANCY
The presence of pregnancy is naturally determined by the recognition of those changes in the maternal system which the growing ovum produces.
During the second half of the period the fœtus can be made out distinctly by palpation, or by its movements, and the heart tones observed by auscultation.
During the first half this is impossible and the diagnosis must be made from subjective symptoms elicited from the patient and upon physical signs observed by the physician.
It is of extreme practical importance to be able to recognize a pregnancy at all periods. The subjective symptoms of the first half are—amenorrhœa, morning sickness, irritability of the bladder, discomfort and swelling of the breasts, enlargement of the abdomen and quickening; but the appearance of any or all of these phenomena is not to be regarded as conclusive, but merely as a presumption that pregnancy exists. Either through ignorance, intent to deceive, or from pathological conditions, any or all of these symptoms may be present, but not until the tenth week are the changes in the uterus sufficiently definite to confirm a diagnosis unless the circumstances are especially favorable.
Amenorrhœa.—Cessation of the menses is practically invariable in pregnancy. One or two periods may occur after conception, but care must be used to exclude other causes of hæmorrhage. Sudden cessation of the periods in a healthy woman of regular habits who is not near the menopause, is strongly suggestive of pregnancy. Why a developing ovum causes an immediate arrest of menstruation is not understood.
Amenorrhœa may occur in consequence of chlorosis, heart disease, hysteria, tuberculosis, fright, grief, and some forms of insanity; a change from a low to a high altitude, or an ocean voyage not infrequently causes the flow to remain absent for one or more months. In addition to its value as a presumptive symptom, the amenorrhœa affords a common and convenient method of estimating the date of confinement. The method is fallacious but practical, and will be discussed later.