=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.