| Pregnant women typically produce a mucus plug to obstruct the cervical canal. Under the influence of pregnancy hormones, the cervix becomes a violet color due to increased vasculature. Other changes in preparation for delivery include the loosening of connective tissue, an increase in the mucosal thickness, and hypertrophy of vaginal and perineal muscular cells. Many other changes take place in pregnancy,most notably an increase in blood volume to 40-45% above nonpregnant levels, so that the oxygen demands of the enlarged uterus can be met, and so the mother and fetus are both protected from impaired venous return due to occlusion of the pelvic veins and the inferior vena cava by the expanded uterus. The increased blood volume also protects the mother from adverse effects of blood loss associated with delivery. Cardiac output is further increased by an increase in heart rate by about 10 beats per minute. [1] | | | | |