title: Unexplained first trimester recurrent pregnancy loss and low venous reserves.
abstract: BACKGROUND
  More than half of recurrent pregnancy loss (RPL) remains unexplained. We hypothesized that women with a history of unexplained RPL (URPL) have low venous reserve.
  
  
  METHODS
  Case-control study in 12 women with a history of URPL, 11 healthy nulliparous controls and 12 primiparous controls with a history of uncomplicated pregnancy. To quantify venous reserve, we measured plasma volume (PV, ml/m(2)) and venous compliance in forearm and calf (VC(arm), VC(calf), (ml/dl)/mmHg) during the follicular phase of the menstrual cycle. Mean arterial blood pressure (mmHg) was measured by oscillometry. Arterial demand was evaluated by cardiac index (CI, (l/min)/m(2)).
  
  
  RESULTS
  Baseline characteristics were comparable between groups. All groups had similar CI. Women with a history of RPL had 14% and 9% lower mean PV compared with nulliparous and primiparous controls (P < 0.01 and P = 0.04, respectively). In women with URPL, the mean VC(arm) was 25% and 32% lower compared with nulliparous and primiparous controls (P = 0.04 and P < 0.01, respectively), while the mean VC(calf) was 29 and 22% lower compared with the two control groups (P < 0.01 and P = 0.03, respectively).
  
  
  CONCLUSIONS
  Women with URPL have lower venous reserves when compared with controls at comparable arterial demand. Interventions that increase venous reserve may improve pregnancy outcome.
authors: Department of Obstetrics and Gynecology, Radboud University Nijmegen Medical Centre, PO Box 9101, Nijmegen 6500 HB, The Netherlands. j.donckers@obgyn.umcn.nl
authors: Janneke
authors: J
authors: Donckers
authors: Ralph R
authors: RR
authors: Scholten
authors: Wim J G
authors: WJ
authors: Oyen
authors: Maria T E
authors: MT
authors: Hopman
authors: Fred K
authors: FK
authors: Lotgering
authors: Marc E A
authors: ME
authors: Spaanderman
mesh_terms: D000026:Abortion, Habitual / Q000097:blood* / Q000175:diagnosis*; D000328:Adult; D062186:Arterial Pressure; D001794:Blood Pressure; D015992:Body Mass Index; D016022:Case-Control Studies; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008597:Menstrual Cycle; D009991:Oscillometry / Q000379:methods; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D013997:Time Factors; D014680:Veins / Q000503:physiopathology