Explanation/Reference:
Explanation:
(A) Nausea and vomiting are experienced by almost half of all pregnant women during the first 3 months of pregnancy as a result of elevated human chorionic gonadotropin levels and changed carbohydrate metabolism. (B) Quickening is the mother's perception of fetal movement and generally does not occur until 18-20 weeks after the last menstrual period in primigravidas, but it may occur as early as 16 weeks in multigravidas. (C) During the first trimester there should be only a modest weight gain of 2-4 lb. It is not uncommon for women to lose weight during the first trimester owing to nausea and/or vomiting. (D) Physical changes are not apparent until the second trimester, when the uterus rises out of the pelvis.