Maternal adaptations to pregnancy: Physiologic respiratory changes and dyspnea
- Steven E Weinberger, MD
Steven E Weinberger, MD
- Adjunct Professor of Medicine
- University of Pennsylvania School of Medicine
- Executive Vice President and CEO Emeritus
- American College of Physicians
- Section Editors
- Charles J Lockwood, MD, MHCM
Charles J Lockwood, MD, MHCM
- Section Editor — Obstetrics
- Senior Vice President, USF Health
- Dean, Morsani College of Medicine
- Professor, Obstetrics and Gynecology
- University of South Florida
- Peter J Barnes, DM, DSc, FRCP, FRS
Peter J Barnes, DM, DSc, FRCP, FRS
- Editor-in-Chief — Pulmonary and Critical Care Medicine
- Section Editor — Asthma
- Professor of Medicine
- National Heart and Lung Institute, Imperial College, London
Dyspnea, or breathing discomfort, is common during pregnancy. Dyspnea during pregnancy can represent either underlying or new cardiac or pulmonary disease, or, more commonly, be a result of the pregnancy itself.
PHYSIOLOGICAL CHANGES IN PREGNANCY POTENTIALLY AFFECTING RESPIRATION
Distinguishing physiologic dyspnea of pregnancy from other causes requires an understanding of both the cardiopulmonary changes that occur during normal pregnancy and the syndrome of dyspnea during normal pregnancy [1-4]. Both cardiovascular and respiratory changes accompany normal pregnancy.
Cardiovascular changes — The most striking cardiovascular changes during pregnancy are increases in blood volume and cardiac output [5-7].
●Blood volume – Blood volume starts to rise during the first trimester and eventually reaches a maximum that is 40 to 50 percent above the baseline, nonpregnant blood volume. Because plasma volume increases more than red cell mass, the hematocrit generally falls, resulting in the physiologic "anemia of pregnancy" (figure 1). (See "Maternal adaptations to pregnancy: Hematologic changes".)
●Cardiac output – Cardiac output also starts to rise in the first trimester, reaching a peak at 20 to 32 weeks of gestation that is 30 to 50 percent above baseline (figure 2) [7,8]. Although the increase in cardiac output is initially due to a rise in stroke volume, the increase is maintained later in pregnancy by an increase in heart rate, as stroke volume falls during the third trimester. Decreases in systemic vascular resistance and pulmonary vascular resistance accompany the increase in cardiac output . Blood pressure during pregnancy is often notable for a rise in pulse pressure due to an unchanged systolic pressure accompanied by a decrease in diastolic pressure. (See "Maternal cardiovascular and hemodynamic adaptations to pregnancy".)
- Pereira A, Krieger BP. Pulmonary complications of pregnancy. Clin Chest Med 2004; 25:299.
- Graves CR. Acute pulmonary complications during pregnancy. Clin Obstet Gynecol 2002; 45:369.
- Ie S, Rubio ER, Alper B, Szerlip HM. Respiratory complications of pregnancy. Obstet Gynecol Surv 2002; 57:39.
- Burdon J. Breathlessness and pregnancy. Aust Fam Physician 2000; 29:451.
- Zeldis SM. Dyspnea during pregnancy. Distinguishing cardiac from pulmonary causes. Clin Chest Med 1992; 13:567.
- Longo LD. Maternal blood volume and cardiac output during pregnancy: a hypothesis of endocrinologic control. Am J Physiol 1983; 245:R720.
- Setaro JF, Caulin-Glaser T. Pregnancy and cardiovascular disease. In: Medical Complications During Pregnancy, 6th ed, Burrow GN, Duffy TP, Copel JA (Eds), Elsevier Saunders, Philadelphia 2004.
- Robson SC, Hunter S, Boys RJ, Dunlop W. Serial study of factors influencing changes in cardiac output during human pregnancy. Am J Physiol 1989; 256:H1060.
- Sharma R, Kumar A, Aneja GK. Serial Changes in Pulmonary Hemodynamics During Pregnancy: A Non-Invasive Study Using Doppler Echocardiography. Cardiol Res 2016; 7:25.
- Turner AF. The chest radiograph in pregnancy. Clin Obstet Gynecol 1975; 18:65.
- Thomson, K, Cohen, M. Studies on the circulation in normal pregnancy: II. Vital capacity observations in normal pregnant women. Surg Gynecol Obstet 1938; 66:591.
- Weinberger SE, Weiss ST, Cohen WR, et al. Pregnancy and the lung. Am Rev Respir Dis 1980; 121:559.
- Gilroy RJ, Mangura BT, Lavietes MH. Rib cage and abdominal volume displacements during breathing in pregnancy. Am Rev Respir Dis 1988; 137:668.
- Mandel J, Weinberger SE. Pulmonary diseases. In: Medical Complications During Pregnancy, 6th ed, Burrow GN, Duffy TP, Copel JA (Eds), Elsevier Saunders, Philadelphia 2004.
- Hegewald MJ, Crapo RO. Respiratory physiology in pregnancy. Clin Chest Med 2011; 32:1.
- CUGELL DW, FRANK NR, GAENSLER EA, BADGER TL. Pulmonary function in pregnancy. I. Serial observations in normal women. Am Rev Tuberc 1953; 67:568.
- PROWSE CM, GAENSLER EA. RESPIRATORY AND ACID-BASE CHANGES DURING PREGNANCY. Anesthesiology 1965; 26:381.
- Milne JA, Mills RJ, Coutts JR, et al. The effect of human pregnancy on the pulmonary transfer factor for carbon monoxide as measured by the single-breath method. Clin Sci Mol Med 1977; 53:271.
- McAuliffe F, Kametas N, Costello J, et al. Respiratory function in singleton and twin pregnancy. BJOG 2002; 109:765.
- Elkus R, Popovich J Jr. Respiratory physiology in pregnancy. Clin Chest Med 1992; 13:555.
- Yannone ME, McCurdy JR, Goldfien A. Plasma progesterone levels in normal pregnancy, labor, and the puerperium. II. Clinical data. Am J Obstet Gynecol 1968; 101:1058.
- Lim VS, Katz AI, Lindheimer MD. Acid-base regulation in pregnancy. Am J Physiol 1976; 231:1764.
- Andersen GJ, James GB, Mathers NP, et al. The maternal oxygen tension and acid-base status during pregnancy. J Obstet Gynaecol Br Commonw 1969; 76:16.
- Templeton A, Kelman GR. Maternal blood-gases, PAo2--Pao2), hysiological shunt and VD/VT in normal pregnancy. Br J Anaesth 1976; 48:1001.
- Mellemgaard K. The alveolar-arterial oxygen difference: its size and components in normal man. Acta Physiol Scand 1966; 67:10.
- Deutsch AB, Twitty P, Downes K, Parsons MT. Assessment of the alveolar-arterial oxygen gradient as a screening test for pulmonary embolism in pregnancy. Am J Obstet Gynecol 2010; 203:373.e1.
- Toppozada H, Michaels L, Toppozada M, et al. The human respiratory nasal mucosa in pregnancy. An electron microscopic and histochemical study. J Laryngol Otol 1982; 96:613.
- Simon PM, Schwartzstein RM, Weiss JW, et al. Distinguishable types of dyspnea in patients with shortness of breath. Am Rev Respir Dis 1990; 142:1009.
- Hytten FE, Leitch I. Respiration. In: The Physiology of Human Pregnancy, Blackwell Scientific Publications, Oxford 1971.
- Al-Damluji S. The effect of ventilatory stimulation with medroxyprogesterone on exercise performance and the sensation of dyspnoea in hypercapnic chronic bronchitis. Br J Dis Chest 1986; 80:273.
- Robertson HT, Schoene RB, Pierson DJ. Augmentation of exercise ventilation by medroxyprogesterone acetate. Clin Physiol 1982; 2:269.
- Goland S, Perelman S, Asalih N, et al. Shortness of Breath During Pregnancy: Could a Cardiac Factor Be Involved? Clin Cardiol 2015; 38:598.
- Garg J, Palaniswamy C, Lanier GM. Peripartum cardiomyopathy: definition, incidence, etiopathogenesis, diagnosis, and management. Cardiol Rev 2015; 23:69.
- Pratter MR, Hingston DM, Irwin RS. Diagnosis of bronchial asthma by clinical evaluation. An unreliable method. Chest 1983; 84:42.
- Curley FJ, Irwin RS, Pratter MR, et al. Cough and the common cold. Am Rev Respir Dis 1988; 138:305.
- Pratter MR, Curley FJ, Dubois J, Irwin RS. Cause and evaluation of chronic dyspnea in a pulmonary disease clinic. Arch Intern Med 1989; 149:2277.
- Bohadana A, Izbicki G, Kraman SS. Fundamentals of lung auscultation. N Engl J Med 2014; 370:744.
- Dieter RA Jr, Kuzycz GB, Dieter RA 3rd. Malignant and benign thoracic tumors during pregnancy. Int Surg 2006; 91:S103.
- Ersbøll AS, Damm P, Gustafsson F, et al. Peripartum cardiomyopathy: a systematic literature review. Acta Obstet Gynecol Scand 2016; 95:1205.
- Bonebrake CR, Noller KL, Loehnen CP, et al. Routine chest roentgenography in pregnancy. JAMA 1978; 240:2747.
- Leung AN, Bull TM, Jaeschke R, et al. American Thoracic Society documents: an official American Thoracic Society/Society of Thoracic Radiology Clinical Practice Guideline--Evaluation of Suspected Pulmonary Embolism in Pregnancy. Radiology 2012; 262:635.
- Resnik JL, Hong C, Resnik R, et al. Evaluation of B-type natriuretic peptide (BNP) levels in normal and preeclamptic women. Am J Obstet Gynecol 2005; 193:450.
- Graves CR. Acute pulmonary complications in pregnancy. In: Textbook of critical care, Fink MP, Abraham E, Vincent J, Kochanek PM (Eds), Elsevier Saunders, Philadelphia 2005. p.1551.
- Wolfe LA, Weissgerber TL. Clinical physiology of exercise in pregnancy: a literature review. J Obstet Gynaecol Can 2003; 25:473.
- Heenan AP, Wolfe LA, Davies GA. Maximal exercise testing in late gestation: maternal responses. Obstet Gynecol 2001; 97:127.
- Baciuk EP, Pereira RI, Cecatti JG, et al. Water aerobics in pregnancy: Cardiovascular response, labor and neonatal outcomes. Reprod Health 2008; 5:10.
- PHYSIOLOGICAL CHANGES IN PREGNANCY POTENTIALLY AFFECTING RESPIRATION
- Cardiovascular changes
- Respiratory changes
- Dyspnea of pregnancy
- EVALUATION OF PREGNANT WOMEN WITH DYSPNEA
- Initial evaluation
- - History and physical examination
- Does the patient have underlying pulmonary or cardiac disease?
- Is dyspnea of acute or gradual onset?
- Is cough present?
- Is the chest clear on auscultation?
- Are other symptoms present?
- Is onset early in gestation or near term?
- Additional clues
- - Laboratory and imaging tests
- Additional testing
- Indications for prompt referral
- WOMEN WITH RESPIRATORY INSUFFICIENCY
- INFORMATION FOR PATIENTS
- SUMMARY AND RECOMMENDATIONS