=When to Expect the Baby.= Now that you are familiar with the most apparent changes which will take place in your body during pregnancy, you are probably on tiptoe to find out as nearly as possible the date upon which to expect the baby. Unfortunately we cannot foretell the exact date, for the very simple reason that we have no way of knowing just when pregnancy begins. Quite evidently, then, not knowing when it begins we cannot figure out the exact date upon which pregnancy will end in the baby’s birth. But we do know that labor usually begins about ten lunar months, or forty weeks, or from 273 to 280 days, after the beginning of the last menstrual period. Thus the approximate date of the baby’s arrival may be estimated by counting forward 280 days or backward 85 days from the first day of the last period. Or, what is perhaps simpler and amounts to the same thing, one may add seven days to the first day of the last period and count back three months. For example, if the last period began on June 3, the addition of seven days brings us to June 10, while counting back three months from this, indicates March 10 as the approximate date upon which the baby may be expected. This is probably as satisfactory as any method of estimation, but at best it is only approximate, being accurate in about one case in twenty. However, it comes within a week of being correct in half the cases; and is within two weeks of the actual date in eighty per cent. of all pregnancies. Still another method is to count forward twenty or twenty-two weeks from the day upon which you first feel the baby move. This “quickening,” as we have seen, usually occurs about the eighteenth or twentieth week, but is so irregular that it is not wholly reliable. The possibility of figuring out the date of the baby’s arrival is made still more uncertain by the fact that there is evidently considerable variation in the length of entirely normal pregnancies. Many healthy children are born before ten lunar months have elapsed since the last menstrual period, while more births occur after than on the expected date. The first pregnancy is usually shorter than later ones, and women who are well nourished and well cared for usually have longer pregnancies than those who are not. Taking it as a whole, the average woman has unusually good health during pregnancy. She may feel some weariness during the first few months and she may lose a little weight, but during the latter part of the period her general health is improved and there is an increase of flesh, not alone in the abdomen, but over the entire body, sometimes amounting to twenty-five or thirty pounds. She loses about fifteen pounds of the increased weight when the baby is born, and still more during the weeks immediately following, when her body returns to about its original condition. But very often the experience of pregnancy is so beneficial that the improved state of health and nutrition which accompany it become permanent.