Harrison's Internal Medicine Part 1. Introduction to Clinical Medicine Chapter 7. Medical Disorders during Pregnancy Medical Disorders during Pregnancy: Introduction Approximately 4 million births occur in the United States each year. A significant proportion of these are complicated by one or more medical disorders. Three decades ago, many medical disorders were contraindications to pregnancy. Advances in obstetrics, neonatology, obstetric anesthesiology, and medicine have increased the expectation that pregnancy will result in an excellent outcome for both mother and fetus despite most of these conditions. Successful pregnancy requires important physiologic adaptations, such as a marked increase in cardiac output. . | Chapter 007. Medical Disorders during Pregnancy Part 1 Harrison s Internal Medicine Part 1. Introduction to Clinical Medicine Chapter 7. Medical Disorders during Pregnancy Medical Disorders during Pregnancy Introduction Approximately 4 million births occur in the United States each year. A significant proportion of these are complicated by one or more medical disorders. Three decades ago many medical disorders were contraindications to pregnancy. Advances in obstetrics neonatology obstetric anesthesiology and medicine have increased the expectation that pregnancy will result in an excellent outcome for both mother and fetus despite most of these conditions. Successful pregnancy requires important physiologic adaptations such as a marked increase in cardiac output. Medical problems that interfere with the physiologic adaptations of pregnancy increase the risk for poor pregnancy outcome conversely in some instances pregnancy may adversely impact an underlying medical disorder. Hypertension See also Chap. 241 In pregnancy cardiac output increases by 40 most of which is due to an increase in stroke volume. Heart rate increases by 10 beats min during the third trimester. In the second trimester of pregnancy systemic vascular resistance decreases and this is associated with a fall in blood pressure. During pregnancy a blood pressure of 140 90 mmHg is considered to be abnormally elevated and is associated with an increase in perinatal morbidity and mortality. In all pregnant women the measurement of blood pressure should be performed in the sitting position because for many the lateral recumbent position is associated with a blood pressure lower than that recorded in the sitting position. The diagnosis of hypertension requires the measurement of two elevated blood pressures at least 6 h apart. Hypertension during pregnancy is usually caused by preeclampsia chronic hypertension gestational hypertension or renal disease. Preeclampsia Approximately 5-7 of all pregnant women
