A variety of different physiological changes occur in the woman during pregnancy. Her heart rate increases as does the amount of circulating blood. She breathes more deeply and kidney function is increased. Additionally, many smooth muscles relax and the production of certain hormones is dramatically increased. These changes occur to help maintain the pregnancy.
Many factors affect the likelihood of a safe pregnancy outcome for the mother and the baby.
In general, pregnancy is safe for women. The likelihood of death for a mother is very small, in the range of 10 to 20 maternal deaths per 100,000 live births. Mortality figures have shown constant improvement since the delivery site moved from the home to the hospital, and may be even lower than those noted above with optimal care. The same is true for likelihood of a healthy baby. This may complicate up to 15 percent of all clinically recognized pregnancies.