Pregnancy causes anatomical changes like enlargement of the uterus and weight gain. Metabolic changes like increased thyroid and breast maturation occur due to hormones from the placenta. Physiological changes impact many systems - morning sickness is common, kidneys work harder, breathing becomes strained. During labor, contractions dilate the cervix until birth, then the placenta is delivered. The infant is assessed with Apgar scores. Lactation is stimulated by hormones to provide breast milk advantages to the newborn.