ABC | Volume 114, Nº5, May 2020

Statement Brazilian Cardiology Society Statement for Management of Pregnancy and Family Planning in Women with Heart Disease – 2020 Arq Bras Cardiol. 2020; 114(5):849-942 Table 1 – Hemodynamic alterations during gestation Parameter Alteration Cardiac output Increased 30% to 50% (2l/min) Heart rate Increased 15% to 20% (15 bpm) Blood volume Increased 20% to 30% (1.8 l) Average arterial pressure Reduced at least 5% Systemic vascular resistance Reduced 20% to 30% (320 dynes-s/cm5) Pulmonary vascular resistance Reduced 30% (40 dynes-s/cm5) Central venous pressure Unaltered Lower limb venous pressure Increased 15% Medicine is increasingly individualizing the approach to diverse diseases, especially in relation to gender, given that the female organism differs greatly from the male one, especially during the pregnancy-postpartum cycle. The updating of this document fulfills the universal responsibility regarding improving maternal-fetal prognosis. It is, thus, undeniable that the DCM’s accumulated experience contributes to the establishment of protocols that guide therapeutic practice during pregnancy, to the counseling of future pregnancies, to improvements in life expectancy with quality, and to the reduction in maternal mortality due to heart disease. In consonance with the international literature, this document discusses new concepts of heart disease versus pregnancy, including the following: maternal risk stratification based on the recommendations of the World Health Organization (WHO); aspects of arterial hypertension; reinforcing interdisciplinary approaches, with the participation of a heart team; therapeutic proposals for complications; changes in the classification of maternal-fetal risks with respect to drugs used during pregnancy and breastfeeding; and contraception. The objectives of this publication are to standardize routine and to divulge yet another tool that will be useful in daily clinical practice. The DCM hopes that the recommendations included in this document will have positive impact throughout Brazil and that they will contribute to better treatment and consequent reduction of cardiovascular risks in childbearing women with heart disease. 2. General Considerations 2.1. Physiological Adaptation to Pregnancy, Labor and Delivery Interaction between the embryo and the maternal uterus provokes intrinsic hormonal stimulation in the organism and alterations in the physiology of the cardiovascular system, which are fundamental to the adequate development of pregnancy. 1 These changes, however, lead to a hemodynamic overload that may reveal previously unrecognized heart diseases or aggravate the functional state of underlying heart diseases. For this reason, it is fundamental to comprehend the hemodynamic, blood coagulation, and respiratory modifications that occur during the pregnancy, labor and delivery in order to understand the maternal clinical condition, to predict risks of gestation, and to evaluate fetal health. 2.1.1. Hemodynamic Modifications (Table 1) Cardiac output, which is calculated by the product of systolic volume and heart rate, progressively increases, on average, 40% higher than preconception values, beginning of the first trimester of gestation, reaching the greatest increasing in onset of third trimester and tending to reduce at the term of pregnancy 2 (Figure 1). The magnitude of the increase in cardiac output varies individually, and it is 15% greater in multiple pregnancies. Plasma volume is principal responsible for the increase in cardiac output during the first half of gestation. From that moment onwards, heart rate, which does not usually exceed 100 beats per minute (bpm), plays an important role in this increase until the term of pregnancy. The disproportion between increased plasma volume and the production of red blood cells results in haemoglobin dilution or physiological anemia of pregnancy. This is most evident during the end of the second trimester, when plasma volume reaches its peak in relation to the volume of blood cells. When the renal function is normal, blood volume and others elements return to preconception values on account of diuresis, eight weeks after delivery, while hemoglobin begins to increase on the third postpartum day. 2,3 At the term of pregnancy, blood volume is estimated at 100 ml/kg, almost two times higher than the value of 65 to 70 ml/kg found in women who are not pregnant. Erythrocyte mass begins to increase between the eighth and tenth week of pregnancy, induced by the elevation of plasma erythropoietin. The hormonal mechanisms of the hypervolemia during pregnancy include increasing levels of estrogen and progesterone, which increases renin levels, causing retention of sodium and total body water; prolactin; placental lactogen; prostaglandins; and the growth hormone. After the second half of pregnancy, variations may be observed in resting cardiac output consequential to the position adopted by pregnant women. The change from dorsal decubitus to left lateral, for instance, produces an approximately 22% increase in cardiac output, an 854