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The incidence of surgery during pregnancy is between 0.3% and 2.0%.1,2 There are approximately 4,000,000 deliveries per year in the United States; this translates to approximately 80,000 anesthetics per year administered to pregnant women for intercurrent surgical procedures. In actuality, this may be an underestimate due to surgery performed prior to clinical recognition of the pregnancy. Surgery may be required at any time during pregnancy, and appendectomy is the most frequently performed nonobstetric operation.3
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Anesthesia for the pregnant woman is one of the rare situations where the anesthesiologist contends with two patients—the mother and the unborn fetus. Therefore, providing a safe anesthetic requires an understanding of the physiologic changes of pregnancy and the impact of anesthesia and surgery on the developing fetus.
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PHYSIOLOGIC CHANGES OF PREGNANCY
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The pregnant woman undergoes significant physiologic changes to allow adaptation for the developing fetus. These changes are discussed in Chapter 1 and summarized in Table 12-1.
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A teratogen is a substance that produces an increase in the incidence of a defect that cannot be attributed to chance. To produce a defect, the teratogen must be administered in a sufficient dose at a critical point in development. In humans, this critical point is during organogenesis, which extends from 15 to approximately 60 days gestational age. Each organ system has its own unique period of susceptibility depending on ...