Usually, after two menstrual periods have been missed the breasts increase in size and firmness, and often the veins which run just beneath the skin stand out conspicuously. Before very long it is possible to squeeze from the breasts a fluid which many persons believe to be milk, though it is really colostrum, a substance that resembles milk but very slightly. At first colostrum is a clear, white fluid, but in the later months of pregnancy it becomes yellow and cloudy. None of the changes in the breasts are absolutely characteristic of pregnancy; even the secretion of colostrum has been noted in association with various other conditions. Furthermore, as a sign of pregnancy the presence of colostrum is totally deprived of value in the case of a woman who has recently nursed an infant, for a small quantity of milk or colostrum often remains in the breasts for months after the infant is weaned. In general, however, women who have not been pregnant before should assume that they have conceived if, after missing a menstrual period, they note the characteristic changes in the breasts. _Morning Sickness_.--Soon after conception many women suffer from nausea and vomiting, especially on rising in the morning. "Morning sickness" usually passes off in a few hours, although it may be more persistent. Perhaps this manifestation occurs more frequently in the first than in subsequent pregnancies, but certainly one-half, and probably two-thirds, of all prospective mothers suffer from it. Usually the nausea begins just after a menstrual period has been missed, and ceases about the third month or a little later. But morning sickness is never counted an indication of pregnancy unless taken in conjunction with other symptoms, for individuals who are not pregnant may also suffer from nausea in the morning. On the other hand, a number of prospective mothers escape morning sickness altogether, and a few experience nausea at other times of day. _Disturbances in Urination_.--It is not an uncommon belief that some characteristic change occurs in the urine shortly after conception. But this is not true; at least no change is revealed by any method of analysis known at present. Yet there are symptoms associated with the passage of the urine which appear very promptly and prevail for several weeks. Chief among these is the desire to empty the bladder frequently; some patients also have difficulty in urination, and a few experience discomfort with it. All the bladder symptoms gradually disappear about the fourth month, but become prominent again toward the end of pregnancy.