Pregnancy-Induced Physiologic Alterations
50 Laird-Meeter K, van de Ley G, Bom TH, et al. Cardiocirculatory adjustments during pregnancy – an echocardiographic study. Clin Cardiol 1979; 2: 328–332.
51 Mashini IS, Albazzaz SJ, Fadel HE, et al. Serial noninvasive evalua-tion of cardiovascular hemodynamics during pregnancy. Am J Obstet Gynecol 1987; 156: 1208–1214.
52 Easterling TR , Benedetti TJ, Schmucker BC , Millard SP. Maternal hemodynamics in normal and preeclamptic pregnancies: a longitu-dinal study. Obstet Gynecol 1990; 76: 1061–1069.
53 Van Oppen ACC, van der Tweel I, Alsbach GPJ, et al. A longitudinal study of maternal hemodynamics during normal pregnancy. Obstet Gynecol 1996; 88: 40–46.
54 Mabie WC, DiSessa TG, Crocker LG, et al. A longitudinal study of cardiac output in normal human pregnancy. Am J Obstet Gynecol 1994; 170: 849–856.
55 Pombo JF, Troy BL , Russell RO. Left ventricular volumes and ejec-tion fraction by echocardiography. Circulation 1971; 43: 480–490.
56 Murray JA, Johnston W, Reid JM. Echocardiographic determination of left ventricular dimensions, volumes, and performance. Am J Cardiol 1972; 30: 252–257.
57 Easterling TR, Watts DH, Schmucker BC, Benedetti TJ. Measurement of cardiac output during pregnancy: validation of Doppler tech-nique and clinical observations in preeclampsia. Obstet Gynecol 1987; 69: 845–850.
58 Robson SC, Dunlop W, Boys RJ, Hunter S. Cardiac output during labor. BMJ 1987; 295: 1169–1172.
59 Robson SC, Dunlop W, Moore M, Hunter S. Combined Doppler and echocardiographic measurement of cardiac output: theory and appli-cation in pregnancy.Br J Obstet Gynaecol 1987; 94: 1014–1027.
60 Robson SC, Hunter S, Moore M, Dunlop W. Haemodynamic changes during the puerperium: a Doppler and M-mode echocar-diographic study. Br J Obstet Gynaecol 1987; 94: 1028–1039.
61 Lee W, Rokey R, Cotton DB. Noninvasive maternal stroke volume and cardiac output determinations by pulsed Doppler echocardiog-raphy. Am J Obstet Gynecol 1988; 158: 505–510.
62 Capeless EL, Clapp JF. When do cardiovascular parameters return
70 Schrier RW. Pathogenesis of sodium and water retention in high-output and low - output cardiac failure, nephrotic syndrome, cir-rhosis, and pregnancy. N Engl J Med 1988; 319: 1127–1134.
71 Schrier RW. Body ﬂuid volume regulation in health and disease: a unifying hypothesis . Ann Intern Med 1990; 113: 155–159.
72 Seligman SP, Kadner SS, Finlay TH. Relationship between pre-eclampsia, hypoxia, and production of nitric oxide by the placenta. Am J Obstet Gynecol 1996 ; 174 : abstract.
73 Brenner BM, Ballermann BJ, Gunning ME, Zeidel ML. Diverse bio-logical actions of atrial natriuretic peptide . Physiol Rev 1990; 70: 665–669.
74 Cusson JR, Gutkowska, J, Rey E, et al. Plasma concentration of atrial natriuretic factor in normal pregnancy. N Engl J Med 1985; 313: 1230–1231.
75 Thomsen JK, Storm TL, Thamsborg G, et al. Increased concentra-tion of circulating atrial natriuretic peptide during normal preg-nancy. Eur J Obstet Gynecol Reprod Biol 1988; 27: 197–201.
76 Thomsen JK, Fogh-Anderson N, Jaszczak P, Giese J. Atrial natri-uretic peptide (ANP) decrease during normal pregnancy as related to hemodynamic changes and volume regulation. Acta Obstet Gynecol Scand 1993; 72: 103–110.
77 Chesley LC. Renal functional changes in normal pregnancy. Clin Obstet Gynecol 1960; 3: 349.
78 Gabert HA, Miller JM. Renal disease during pregnancy. Obstet Gynecol Surv 1985; 40: 449–461.
79 Katz M , Sokal MM . Skin perfusion in pregnancy. Am J Obstet Gynecol 1980; 137: 30–34.
80 Burt CC. Peripheral skin temperature in normal pregnancy. Lancet 1949; 2: 787.
81 Herbert CM, Banner EA, Wakim KG. Variations in the peripheral circulation during pregnancy. Am J Obstet Gynecol 1958; 76: 742.
82 Kitabatake A, Inoue M, Asao M, et al. Noninvasive evaluation of pulmonary hypertension by a pulsed Doppler technique.Circulation 1983; 68: 302–309.
83 Robson SC, Hunter S, Boys J, Dunlop W. Serial changes in pulmo-
nary haemodynamics during human pregnancy: a non - invasive
to their preconception values? Am J Obstet Gynecol 1991; 165: study using Doppler echocardiography. Clin Sci 1991; 80:
63 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: H1060–1065.
64 Burwell CS, Strayhorn WD, Flickinger D, et al. Circulation during pregnancy. Arch Intern Med 1938; 62: 979.
65 McCalden RA. The inhibitory action of oestradiol-17b and proges-terone on venous smooth muscle . Br J Pharmacol 1975; 53: 183–192.
66 Wook JE, Goodrich SM. Dilation of the veins with pregnancy or with oral contraceptive therapy. Trans Am Clin Climatol Assoc 1964; 76: 174.
67 Slater AJ, Gude N, Clarke IJ, Walters WA. Haemodynamic changes and left ventricular performance during high - dose oestrogen admin-istration to male transsexuals. Br J Obstet Gynaecol 1986; 93: 532–538.
68 Morton M, Tsang H, Hohimer R, et al. Left ventricular size, output, and structure during guinea pig pregnancy. Am J Physiol 1984; 246: R40–48.
69 Kametas NA, McAuliffe F, Krampl E, Chambers J, Nicolaides KH. Maternal cardiac function in twin pregnancy. Obstet Gynecol 2003;
84 Werko L . Pregnancy and heart disease . Acta Obstet Gynecol Scand 1954; 33: 162.
85 Metcalfe J, Romney SL, Ramsy LH,et al. Estimation of uterine blood ﬂow in normal human pregnancy at term. J Clin Invest 1955; 34: 1632.
86 Assali NS, Rauramo L, Peltonen T. Measurement of uterine blood ﬂow and uterine metabolism.VIII. Uterine and fetal blood ﬂ ow and oxygen consumption in early human pregnancy. Am J Obstet Gynecol 1960; 79: 86–98.
87 Ueland K, Parer JT. Effects of estrogens on the cardiovascular system of the ewe. Am J Obstet Gynecol 1966; 96: 400–406.
88 Caton D, Abrams RM, Clapp JF, et al. The effect of exogenous pro-gesterone on the rate of blood ﬂow of the uterus of ovariectomized sheep. Q J Exp Physiol Cogn Med Sci 1974; 59: 225–231.
89 Bieniarz J, Maqueda E, Caldeyro-Barcia R. Compression of aorta by the uterus in late human pregnancy. I. Variations between femoral and brachial artery pressure with changes from hypertension to hypotension. Am J Obstet Gynecol 1966; 95: 795–808.
90 Bieniarz J, Crottogini JJ, Curuchet E , et al. Aortocaval compression by the uterus in late human pregnancy. II. An arteriographic study.
Am J Obstet Gynecol 1968; 100: 204.
91 Kerr MG. Cardiovascular dynamics in pregnancy and labour. Br 114 Ueland K. Maternal cardiovascular dynamics. VII. Intrapartum Med Bull 1968; 24: 19. blood volume changes . Am J Obstet Gynecol 1976; 126:
92 Howard BK, Goodson JH, Mengert WF. Supine hypotensive syn-drome in late pregnancy. Obstet Gynecol 1953; 1: 371.
93 Holmes F. Incidence of the supine hypotensive syndrome in late pregnancy. J Obstet Gynaecol Br Emp 1960; 67: 254.
94 Calvin S, Jones OW, Knieriem K, Weinstein L. Oxygen saturation in the supine hypotensive syndrome. Obstet Gynecol 1988; 71: 872–877.
95 Kinsella SM, Lohmann G. Supine hypotensive syndrome. Obstet Gynecol 1994 ; 83 ( 5 Pt 1 ): 774 – 788 .
96 Lindheimer MD, Katz AI . Renal function in pregnancy. Obstet Gynecol Annu 1972; 1: 139–176.
97 Vorys N, Ullery JC, Hanusek GE. The cardiac output changes in various positions in pregnancy. Am J Obstet Gynecol 1961; 82: 1312.
98 Easterling TR , Schmucker BC , Benedetti TJ. The hemodynamic effects of orthostatic stress during pregnancy. Obstet Gynecol 1988; 72: 550–552.
99 Barron WM , Mujais SK , Zinaman M , et al. Plasma catecholamine responses to physiologic stimuli in normal human pregnancy. Am J Obstet Gynecol 1986; 154: 80–84.
100 Nisell H , Lunell N , Linde B. Maternal hemodynamics and impaired fetal growth in pregnancy-induced hypertension. Obstet Gynecol 1988; 71: 163–166.
101 Clark SL , Cotton DB, Pivarnik JM , et al. Position change and central hemodynamic proﬁle during normal third - trimester pregnancy and postpartum . Am J Obstet Gynecol 1991; 164: 883–887.
102 Hankins GDV, Harvey CJ, Clark SL, et al. The effects of maternal position and cardiac output on intrapulmonary shunt in normal third-trimester pregnancy. Obstet Gynecol 1996; 88: 327–330.
103 Naeye RL, Peters EC. Working during pregnancy: effects on the fetus. Pediatrics 1982; 69: 724–727.
104 Henriksen TB, Hedegaard M , Secher NJ, Wilcox AJ. Standing at
115 Kjeldsen J. Hemodynamic investigations during labor and delivery. Acta Obstet Gynecol Scand 1979; 89(Suppl): 1–252.
116 Lee W, Rokey R, Cotton DB, Miller JF. Maternal hemodynamic effects of uterine contractions by M-mode and pulsed-Doppler echocardiography. Am J Obstet Gynecol 1989; 161: 974–977.
117 Robson SC, Hunter R, Boys W, et al. Changes in cardiac output during epidural anaesthesia for caesarean section. Anaesthesia 1989; 44: 475–479.
118 Pritchard JA, Baldwin RM, Dickey JC, Wiggins KM. Blood volume changes in pregnancy and the puerperium. II. Red blood cell loss and changes in apparent blood volume during and following vaginal delivery, cesarean section, and cesarean section plus total hysterec-tomy. Am J Obstet Gynecol 1962; 84: 1271.
119 Wilcox CF, Hunt AR, Owen FA. The measurement of blood lost during cesarean section . Am J Obstet Gynecol 1959; 77: 772.
120 Newton M, Mosey LM, Egli GE, et al. Blood loss during and imme-diately after delivery. Obstet Gynecol 1961; 17: 9.
121 Cunningham FG, MacDonald PC, Gant NF, Leveno KJ, Gilstrap LC III. The puerperium. In: Cunningham FG, MacDonald PC, Gant NF, Leveno KJ, Gilstrap LC III , eds. Williams’ Obstetrics, 19th edn. Norwalk, CT: Appleton and Lange, 1993: 467.
122 Chesley LC, Valenti C, Uichano L. Alterations in body ﬂuid com-partments and exchangeable sodium in early puerperium. Am J Obstet Gynecol 1959; 77: 1054.
123 Hankins GD, Wendel GD, Cunningham FG, et al. Longitudinal evaluation of hemodynamic changes in eclampsia. Am J Obstet Gynecol 1984; 150: 506–512.
124 Lee W, Cotton DB. Peripartum cardiomyopathy: current concepts and clinical management. Clin Obstet Gynecol 1989; 32: 54–67.
125 Sobol SE, Frenkiel S, Nachtigal D, Wiener D, Teblum C. Clinical
work and preterm delivery. Br J Obstet Gynaecol 1995; 102: manifestations of sinonasal pathology during pregnancy. J
105 Friedman EA, Neff RK. Hypertension-hypotension in pregnancy. Correlation with fetal outcome. JAMA 1978; 239: 2249–2251.
106 Grunberger W, Leodolter S, Parschalk O. Maternal hypotension: fetal outcome in treated and untreated cases. Gynecol Obstet Invest 1979; 10: 32–38.
107 Ng PH, Walters WA. The effects of chronic maternal hypotension during pregnancy. Aust NZ J Obstet Gynaecol 1992; 32: 14–16.
108 Steer PJ, Little MP, Kold-Jensen T, Chapple J, Elliott P. Maternal blood pressure in pregnancy, birth weight, and perinatal mortality in ﬁ rst births: prospective study. BMJ 2004; 329: 1312–1317.
109 Easterling TR, Brateng D, Schmucker B, Brown Z, Millard SP. Prevention of preeclampsia: a randomized trial of atenolol in hyper-dynamic patients before onset of hypertension. Obstet Gynecol 1999; 93: 725–734.
110 Von Dadelszen P, Ornstein MP, Bull SB, Logan AG , Koren G , Magee LA.Fall in mean arterial pressure and fetal growth restriction in pregnancy hypertension: a meta - analysis . Lancet 2000; 355: 87–92.
111 Adams JQ, Alexander AM. Alterations in cardiovascular physiology during labor. Obstet Gynecol 1958; 12: 542.
112 Hendricks ECH, Quilligan EJ. Cardiac output during labor. Am J Obstet Gynecol 1958; 76: 969.
113 Winner W, Romney SL. Cardiovascular responses to labor and
delivery. Am J Obstet Gynecol 1966; 96: 1004.
Otolaryngol 2001; 30: 24–28.
126 Braithwaite JM, Economides DL. Severe recurrent epistaxis causing antepartum fetal distress. Int J Gynaecol Obstet 1995; 50: 197–198.
127 Howard DJ. Life-threatening epistaxis in pregnancy. J Laryngol Otol 1985; 99: 95–96.
128 MacKenzie JN. The physiological and pathological relations between the nose and the sexual apparatus of man. Alienist Neurol 1898; 19: 219.
129 Mabry RL. Rhinitis of pregnancy. South Med J 1986; 79: 965.
130 Schatz M, Zieger RS. Diagnosis and management of rhinitis during pregnancy. Allergy Proc 1988; 9: 545–554.
131 Mortimer H, Wright RP, Collip JB. The effect of the administration of oestrogenic hormones on the nasal mucosa of the monkey (Macata mulatta). Can Med Assoc J 1936; 35: 504.
132 Taylor M. An experimental study of the inﬂuence of the endocrine system on the nasal respiratory mucosa. J Laryngol Otol 1961; 75: 972.
133 Toppozada H , Michaels L , Toppozada M , et al. The human respira-tory mucosa in pregnancy. J Laryngol Otol 1982; 96: 613–626.
134 Reynolds SRM, Foster FI. Acetylcholine-equivalent content of the nasal mucosa in rabbits and cats, before and after administration of estrogen. Am J Physiol 1940; 131: 422.
135 Contreras G, Guitierrez M, Beroiza T, et al. Ventilatory drive and respiratory muscle function in pregnancy. Am Rev Respir Dis 1991;
Pregnancy-Induced Physiologic Alterations
136 Weinberger SE, Weiss ST, Cohen WR, Weiss JW, Johnson TS. Pregnancy and the lung: state of the art . Am Rev Respir Dis 1980; 121: 559–581.
137 Elkus R, Popovich J. Respiratory physiology in pregnancy.Clin Chest Med 1992; 13: 555–565.
138 Gilroy RJ, Mangura BT, Lavietes MH. Rib cage and abdominal volume displacements during breathing in pregnancy. Am Rev Respir Dis 1988; 137: 668–672.
139 Macklem PT, Gross D, Grassino GA, Roussos C. Partitioning of inspiratory pressure swings between diaphragm and intercostals/ accessory muscles. J Appl Physiol 1978; 44: 200–208.
140 Nava S , Zanotti E , Ambrosino N , Fracchia C , Scarabelli C , Rampulla C. Evidence of acute diaphragmatic fatigue in a “natural”condition. The diaphragm during labor. Am Rev Respir Dis 1992; 146: 1226–1230.
141 Milne JA, Howie AD, Pack AI. Dyspnoea during normal pregnancy. Br J Obstet Gynaecol 1978; 85: 260–264.
142 Thomson JK, Cohen ME. Studies on the circulation in pregnancy. II. Vital capacity observations in normal pregnant women . Surg Gynecol Obstet 1938; 66: 591.
143 Cugell DW, Frank NR , Gaensler EA , Badger TL . Pulmonary function in pregnancy. I. Serial observations in normal women. Am Rev Tuberc 1953; 67: 598.
144 Rubin A, Russo N, Goucher D. The effect of pregnancy upon pul-monary function in normal women . Am J Obstet Gynecol 1956; 72:
159 Hertzberg BS, Carroll BA, Bowie JD, et al. Doppler US assessment of maternal kidneys: analysis of intrarenal resistivity indexes in normal pregnancy and physiologic pelvicaliectasis. Radiology 1993; 186: 689–692.
160 Fried A, Woodring JH, Thompson TJ. Hydronephrosis of preg-nancy. J Ultrasound Med 1983; 2: 255–259.
161 Davison JM, Hytten FE. The effect of pregnancy on the renal han-dling of glucose. Br J Obstet Gynaecol 1975; 82: 374–381.
162 Lindheimer MD, Barron WM. Renal function and volume homeo-stasis . In: Gleicher N , Buttino L , Elkayam U, et al, eds. Principles and Practice of Medical Therapy in Pregnancy , 3rd edn. Stanford, CT: Appleton and Lange, 1998: 1043–1052.
163 Higby K, Suiter CR, Phelps JY, Siler-Khodr T, Langer O. Normal values of urinary albumin and fetal protein excretions during preg-nancy. Am J Obstet Gynecol 1994; 171: 984–989.
164 Barron WM, Lindheimer MD. Renal sodium and water handling in pregnancy. Obstet Gynecol Annu 1984; 13: 35–69.
165 Davison JM, Vallotton MB, Lindheimer MD. Plasma osmolality and urinary concentration and dilution during and after pregnancy. Br J Obstet Gynaecol 1981; 88: 472–479.
166 Baer JL, Reis RA, Artens RA. Appendicitis in pregnancy with changes in position and axis of the normal appendix in pregnancy. JAMA 1932; 98: 1359.
167 Van Thiel DH , Gavaler JS , Joshi SN , Sara RK , Stremple J. Heartburn of pregnancy. Gastroenterology 1977; 72: 666–668.
168 Parry E , Shields R , Turnbull AC . Transit time in the small intestine
145 Gee JB, Packer BS, Millen JE, Robin ED. Pulmonary mechanics in pregnancy. J Obstet Gynaecol Br Commonw 1970; 77:
during pregnancy. J Clin Invest 1967; 46: 945–952.
146 Baldwin GR, Moorthi DS, Whelton JA, MacDonnell KF. New lung functions in pregnancy. Am J Obstet Gynecol 1977; 127: 235–239.
147 Crapo RO. Normal cardiopulmonary physiology during pregnancy. Clin Obstet Gynecol 1996; 39: 3–16.
148 Alaily AB, Carrol KB. Pulmonary ventilation in pregnancy. Br J Obstet Gynaecol 1978; 85: 518–524.
149 Norregard O, Shultz P, Ostergaard A , Dahl R . Lung function and postural changes during pregnancy. Respir Med 1989; 83: 467.
150 Pernoll ML , Metcalfe J, Kovach PA , Wachtel R , Dunham MJ. Ventilation during rest and exercise in pregnancy and postpartum . Respir Physiol 1975; 25: 295–310.
151 Milne JA. The respiratory response to pregnancy. Postgrad Med J 1979; 55: 318–324.
152 Zwillich CW, Natalino MR, Sutton FD, Weil JV. Effects of proges-terone on chemosensitivity in normal men. J Lab Clin Med 1978; 92: 262–269.
153 Bayliss DA, Millhorn DE. Central neural mechanisms of progester-one action: application to the respiratory system.J Appl Physiol 1992; 73: 393–404.
154 Awe RJ, Nicotra MB, Newsom TD, et al. Arterial oxygenation and alveolar – arterial gradients in term pregnancy. Obstet Gynecol 1979; 53: 182–186.
155 Ang CK, Tan TH, Walters WA, et al. Postural inﬂ uence on maternal capillary oxygen and carbon dioxide tension . BMJ 1969; 4: 201–204.
156 Cietak KA, Newton JR. Serial quantitative maternal nephrosonogra-phy in pregnancy. Br J Radiol 1985; 58: 405–414.
157 Shulman A , Herlinger H . Urinary tract dilatation in pregnancy. Br J Radiol 1975; 48: 638–645.
158 Dure - Smith P. Pregnancy dilatation of the urinary tract: the iliac
sign and its signiﬁ cance. Radiology 1970; 96: 545–550.
169 Radberg G, Asztely M, Cantor P, Rehfeld JF, Jarnfeldt-Samsioe A, Svanvik J. Gastric and gall bladder emptying in relation to the secre-tion of cholecystokinin after a meal in late pregnancy. Digestion 1989; 42: 174–180.
170 Vasicka A, Lin TJ, Bright RH. Peptic ulcer and pregnancy: review of hormonal relationships and a report of one case of massive hemor-rhage. Obstet Gynecol Surv 1957; 12: 1.
171 Waldum HL, Straume BK, Lundgren R. Serum group I pepsinogens during pregnancy. Scand J Gastroenterol 1980; 15: 61–64.
172 Braverman DZ, Johnson ML, Kern F. Effects of pregnancy and con-traceptive steroids on gallbladder function . N Engl J Med 1980; 302: 262–264.
173 Girling JC , Dow E , Smith JH . Liver function tests in preeclampsia: importance of comparison with a reference range derived for normal pregnancy. Br J Obstet Gynaecol 1997; 104: 246–250.
174 Pirani BBK , Campbell DM , MacGillivray I . Plasma volume in normal ﬁrst pregnancy. J Obstet Gynaecol Br Commonw 1973; 80: 884–887.
175 Peck TM, Arias F. Hematologic changes associated with pregnancy. Clin Obstet Gynecol 1979; 22: 785–798.
176 Jepson JH, Lowenstein L. Role of erythropoietin and placental lac-togen in the control of erythropoiesis during pregnancy. Can J Physiol Pharmacol 1968; 46: 573–576.
177 Scott DE, Pritchard JA. Iron deﬁciency in healthy young college women. JAMA 1967; 199: 897–900.
178 Pitkin R , Witte D. Platelet and leukocyte counts in pregnancy. JAMA 1979; 242: 2696–2698.
179 Sejeny SA , Eastham RD, Baker SR . Platelet counts during normal pregnancy. J Clin Pathol 1975; 28: 812–814.
180 O’Brien JR. Platelet counts in normal pregnancy. J Clin Pathol 1976;
181 Fenton V, Saunders K, Cavill I. The platelet count in pregnancy. J Clin Pathol 1977; 30: 68–69.
182 Wallenburg HC, van Kessel PH. Platelet lifespan in normal preg-nancy as determined by a nonradioisotopic technique. Br J Obstet Gynaecol 1978; 85: 33–36.
183 Fay RA , Bromham DR , Brooks JA , et al. Platelets and uric acid in the prediction of pre-eclampsia. Am J Obstet Gynecol 1985; 152: 1038–1039.
184 Rakoczi I , Tallian F, Bagdany S , Gati I . Platelet lifespan in normal pregnancy and pre-eclampsia as determined by a non-radioisotope technique. Thromb Res 1979; 15: 553–556.
185 Burrows RF, Kelton JG. Thrombocytopenia at delivery: a prospec-tive survey of 6,715 deliveries. Am J Obstet Gynecol 1990; 162: 731–734.
186 Hellgren M. Hemostasis during pregnancy and puerperium. Hemostasis 1996; 26(Suppl 4): 244–247.
187 Davis GL. Hemostatic changes associated with normal and abnormal pregnancies . Clin Lab Sci 2000; 13: 223–228.
188 Lindqvist P, Dahlback B, Marsal K. Thrombotic risk during
200 Kovats S, Main EK, Librach C, Stubblebine M, Fisher SJ, DeMars R. A class I antigen, HLA-G, expressed in human trophoblasts. Science 1990; 248: 220–224.
201 Bainbridge DR, Ellis SA, Sargent IL. Little evidence of HLA-G mRNA polymorphism in Caucasian or Afro-Caribbean populations. J Immunol 1999; 163: 2023–2027.
202 Allan DS, Colonna M, Lanier LL, et al. Tetrameric complexes of human histocompatibility leukocyte antigen (HLA)-G bind to peripheral blood myelomonocytic cells. J Exp Med 1999; 189: 1149–1156.
203 Starkey PM, Sargent IL, Redman CW. Cell populations in human early pregnancy decidua: characterization and isolation of large granular lymphocytes by ﬂow cytometry. Immunology 1988; 65: 129–134.
204 King A, Burrows T, Verma S, Hiby S, Loke YW. Human uterine lymphocytes. Hum Reprod Update 1998; 4: 480–485.
205 Deniz G, Christmas SE, Brew R, Johnson PM. Phenotypic and func-tional cellular differences between human CD3 - decidual and
peripheral blood leukocytes. J Immunol 1994; 152: 4255–4261.
pregnancy: a population study. Obstet Gynecol 1999; 94:
206 Drake PM, Gunn MD, Charo IF, et al. Human placental cytotropho-
blasts attract monocytes and CD56 (bright) natural killer cells via
189 Gonzalez JG, Elizondo G, Saldivar D, Nanez H, Todd LE, Villarreal JZ . Pituitary gland growth during normal pregnancy: an in vivo study using magnetic resonance imaging. Am J Med 1988; 85: 217–220.
190 Kletzky OA , Rossman F, Bertolli SI , Platt LD, Mischel DR Jr. Dynamics of human chorionic gonadotropin, prolactin, and growth hormone in serum and amniotic ﬂuid throughout normal human pregnancy. Am J Obstet Gynecol 1985; 151: 878–884.
191 Anderson JR . Prolactin in amniotic ﬂuid and maternal serum during uncomplicated human pregnancy. Dan Med Bull 1982; 29: 266.
192 Ballabio M , Poshyachinda M , Ekins RP. Pregnancy - induced changes in thyroid function: role of human chorionic gonadotropin as puta-tive regulator of maternal thyroid. J Clin Endocrinol Metab 1991; 73: 824–831.
193 Nolten WE, Rueckert PA. Elevated free cortisol index in pregnancy: possible regulatory mechanisms. Am J Obstet Gynecol 1981; 139: 492–498.
194 Watanabe M , Meeker CI , Gray MJ, Sims EA , Solomon S . Secretion rate of aldosterone in normal pregnancy. J Clin Invest 1963; 42: 1619.
195 Phelps RL, Metzger BE, Freinkel N. Carbohydrate metabolism in pregnancy. XVII. Diurnal proﬁles of plasma glucose, insulin, free fatty acids, triglycerides, cholesterol, and individual amino acids in late normal pregnancy. Am J Obstet Gynecol 1981; 140: 730–736.
196 Medawar PB. Some immunological and endocrinological problems raised by the evolution of viviparity in vertebrates. Symp Soc Exper Biol 1953; 7: 320.
197 Norwitz ER, Schust DJ, Fisher SJ. Implantation and the survival of early pregnancy. N Engl J Med 2001; 345: 1400–1408.
198 Wilder R. Hormones,pregnancy,and autoimmune diseases.Ann NY Acad Sci 1998; 840: 45–50.
199 Redman CW. HLA-DR antigen on human trophoblast: a review.Am
J Reprod Immunol 1983; 3: 175–177.
the actions of monocyte inﬂammatory protein 1-alpha. J Exp Med 2001; 193: 1199–1212.
207 Roth I, Corry DB, Locksley RM, Abrams JS, Litton MJ, Fisher SJ. Human placental cytotrophoblasts produce the immunosuppressive cytokine interleukin 10. J Exp Med 1996; 184: 539–548.
208 Pavia C, Siiteri PK, Perlman JD, Stites DP. Suppression of murine allogeneic cell interactions by sex hormones . J Reprod Immunol 1979; 1: 33–38.
209 Xu C, Mao D, Holers VM, Palanca B, Cheng AM, Molina H. A criti-cal role for murine complement regulator crry in fetomaternal toler-ance. Science 2000; 287: 498–501.
210 Munn DH, Zhou M, Attwood JT, et al. Prevention of allogeneic fetal rejection by tryptophan catabolism . Science 1998; 281: 1191–1194.
211 Kamimura S, Eguchi K, Yonezawa M, Sekiba K. Localization and developmental change of indoleamine 2,3-dioxygenase activity in the human placenta . Acta Med Okayama 1991; 45: 135–139.
212 Schrocksnadel H, Baier-Bitterlich G, Dapunt O, Wachter H, Fuchs D. Decreased plasma tryptophan in pregnancy. Obstet Gynecol 1996 ; 88: 47–50.
213 Baboonian C , Grifﬁths P. Is pregnancy immunosuppressive? Humoral immunity against viruses. Br J Obstet Gynaecol 1983; 90: 1168–1175.
214 Gitlin D, Kumate J, Morales C , Noriega C , Arevalo N . The turnover of amniotic ﬂuid protein in the human conceptus. Am J Obstet Gynecol 1972; 113: 632–645.
215 Cunningham FG, MacDonald PC, Gant NF, Leveno KJ, Gilstrap LC III . The morphological and functional development of the fetus . In: Cunningham FG, MacDonald PC, Gant NF, Leveno KJ, Gilstrap LC III , eds. Williams’ Obstetrics, 19th edn. Norwalk, CT: Appleton and Lange, 1993: 165–207.
216 Gitlin D. Development and metabolism of the immune globulins. In: Kagan BM , Stiehm ER , eds. Immunologic Incompetence. Chicago:
Year Book , 1971 .
Maternal–Fetal Blood Gas Physiology
Renee A. Bobrowski
Department of Obstetrics and Gynecology, Saint Alphonsus Regional Medical Center, Boise, ID, USA
dioxide (CO 2) gas. Breakdown of proteins and other substances results in 1–1.5 mEq/kg/day of non-volatile or ﬁxed acids (pre-
dominantly phosphoric and sulfuric acids), which are removed
Abnormalities in acid–base and respiratory homeostasis are common among patients requiring intensive medical support, but many clinicians ﬁnd the physiology cumbersome. As a result of both their illness and our therapeutic interventions, critically ill patients frequently require assessment of metabolic and respi-ratory status. An understanding and clinical application of basic physiologic principles is therefore essential to the care of these patients. It is also important that clinicians involved in the care of critically ill gravidas be familiar with the metabolic and respira-tory changes of pregnancy as well as their effect on arterial blood gas interpretation.
The arterial blood gas provides information regarding acid– base balance, oxygenation, and ventilation. A blood gas should be considered when a patient has signiﬁcant respiratory symp-toms or experiences oxygen desaturation, or as a baseline in the evaluation of pre-existing cardiopulmonary disease. In this chapter we focus on fundamental physiology, analytic consider-ations, effective interpretation of an arterial blood gas, and acid –
by the kidneys.
Buffers are substances that can absorb or donate protons and thereby resist or reduce changes in H + ion concentration. Acids produced by cellular metabolism move out of cells and into the extracellular space where buffers absorb the protons. These protons are then transported to the kidney and excreted in urine. The intra - and extracellular buffer systems that maintain homeo-stasis in the human include the carbonic acid–bicarbonate system, plasma proteins, hemoglobin, and bone.
The carbonic acid – bicarbonate system is the principal extracel-lular buffer. Its effectiveness is predominantly due to the ability of the lungs to excrete carbon dioxide. In this system, bicarbon-ate, carbonic acid and carbon dioxide are related by the equation:
CO2 ↔ H2O+CO2 ↔ H2CO3 ↔ H+ +HCO− Gaseous Dissolved Carbonic anhydrase Bicarbonate
Normal acid–base balance depends on production, buffering, and excretion of acid. The delicate balance that is crucial for survival is maintained by buffer systems, the lungs and kidneys. Each day, approximately 15 000 mEq of volatile acids (e.g. carbonic acid) are produced by the metabolism of carbohydrates and fats. These acids are transported to and removed via the lungs as carbon
Critical Care Obstetrics, 5th edition. Edited by M. Belfort, G. Saade,
M. Foley, J. Phelan and G. Dildy. © 2010 Blackwell Publishing Ltd.
Carbon dioxide is produced as an end-product of aerobic metabolism and physically dissolves in body ﬂuids. A portion of dissolved CO 2 reacts with water to form carbonic acid, which dissociates into bicarbonate and hydrogen ions. The concentra-tion of carbonic acid is normally very low relative to that of dis-solved CO2 and HCO3. If the H + ion concentration increases, however, the acid load is buffered by bicarbonate, and additional carbonic acid is formed. The equilibrium of the equation is then driven to the left, and excess acid can be excreted as carbon dioxide gas.
The Henderson–Hasselbalch equation expresses the relation-ship between the reactants of the carbonic acid – bicarbonate
system under conditions of equilibrium: