title: Erythropoiesis and renal transplant pregnancy.
abstract: OBJECTIVE
  To examine erythropoiesis in renal transplant pregnancies.
  
  
  METHODS
  Retrospective cohort study of 30 renal transplant cases and 30 age, smoking and parity-matched healthy controls with normal index pregnancy. Retrospective chart review and assay of frozen antenatal serum (for serum erythropoietin concentration [serum EPO]), transferrin receptor protein [TfR], ferritin, folate and B12) were performed. The linear regression equation for normal pregnancy controls was used to calculate predicted [serum EPO] and the observed/predicted (O/P) log [serum EPO] was plotted. The relationship between [serum EPO] and haemoglobin (Hb) among transplant cases was considered to be different from that among controls if the slope of the O/P log [serum EPO] versus Hb regression was significantly different from zero.
  
  
  RESULTS
  The transplant (14 cadaveric) to conception interval was (median [range]) 33.5 [4, 189] months. Immunosuppressants were azathioprine (n = 25), cyclosporine (n = 22) and/or prednisone (n = 25). Cases were more often primiparous (20 vs. 7 [controls]; p = 0.01), had pre-existent hypertension (20 vs. 0 [controls]; p < 0.001), developed new/increased hypertension or pre-eclampsia (28 vs. 0 [controls]; p < 0.001) and an antenatal rise in creatinine (14 vs. 2 [controls]; p < 0.001). In early pregnancy, cases had similar EPO (15.2 [2.6, 84.6] vs. 15.7 [6.4, 41.0] [controls] U/L) but lower Hb (101 [65, 129] vs. 116 [106, 150] g/L; p < 0.001). Twenty-two (73%) cases had Hb < 100 g/L (vs. 4 [controls]; p < 0.0001); Hb was comparable at 6 wk postpartum. With advancing gestational age (GA), Hb remained stable and serum EPO increased in both groups. The slope of the O/P log [serum EPO] versus Hb for transplant cases was significantly different from zero within both the 17-28 wk (slope +/- SEM: 0.010 +/- 0.002; p < 0.0001) and the 29-42 wk GA categories (0.006 +/- 0.003; p = 0.02). Cases showed smaller rises in serum TfR (change 481 [- 1471, 2780]) vs. 1119 [- 698, 4195] [controls] ng/mL; p = 0.005).
  
  
  CONCLUSIONS
  Anaemia frequently complicates renal transplant pregnancies, in which serum EPO is inappropriately low and the rate of erythropoiesis blunted.
authors.affiliation: Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, University of Oxford, UK. laura.magee@utoronto.ca
authors.forename: L A
authors.initials: LA
authors.lastname: Magee
authors.forename: P
authors.initials: P
authors.lastname: von Dadelszen
authors.forename: J
authors.initials: J
authors.lastname: Darley
authors.forename: Y
authors.initials: Y
authors.lastname: Beguin
mesh_terms: D000328:Adult; D000740:Anemia / Q000209:etiology; D016022:Case-Control Studies; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood; D004920:Erythropoiesis / Q000502:physiology*; D004921:Erythropoietin / Q000097:blood; D005260:Female; D005293:Ferritins / Q000097:blood; D005492:Folic Acid / Q000097:blood; D005865:Gestational Age; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D006973:Hypertension / Q000209:etiology; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000502:physiology*; D016014:Linear Models; D010298:Parity; D011225:Pre-Eclampsia / Q000209:etiology; D011247:Pregnancy / Q000097:blood*; D011249:Pregnancy Complications, Cardiovascular; D011250:Pregnancy Complications, Hematologic; D011990:Receptors, Transferrin / Q000097:blood; D012189:Retrospective Studies; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D006454:Hemoglobins; D007166:Immunosuppressive Agents; D011990:Receptors, Transferrin; D004921:Erythropoietin; D005293:Ferritins; D005492:Folic Acid; D003404:Creatinine; D014805:Vitamin B 12