title: Amniotic fluid fetal hemoglobin in normal pregnancies and pregnancies complicated with preterm labor or prelabor rupture of membranes.
abstract: OBJECTIVE
  Hemoglobin and its catabolic products have been associated with amniotic fluid (AF) discoloration and intra-amniotic infection/inflammation (IAI). However, the origin of AF hemoglobin (maternal or fetal) has not been determined. The aims of this study were to determine if fetal hemoglobin can be detected in AF obtained from normal pregnancies, and whether there is an association between AF fetal hemoglobin concentrations and gestational age, spontaneous labor (term and preterm), preterm prelabor rupture of membranes (PPROM) and IAI.
  
  
  METHODS
  This cross-sectional study included pregnant women in the following groups: (1) mid-trimester (n = 60); (2) term not in labor (n = 21); (3) term in labor (n = 47); (4) spontaneous preterm labor with intact membranes (PTL) without IAI who delivered at term (n = 89); (5) PTL without IAI who delivered preterm (n = 74); (6) PTL with IAI (n = 78); (7) PPROM with (n = 48) and (8) without IAI (n = 48). AF fetal hemoglobin concentrations were determined by ELISA. Non-parametric statistics were used for analyses.
  
  
  RESULTS
  (1) Fetal hemoglobin was detected in 80.4% of all AF samples; (2) women at term not in labor had a higher median AF fetal hemoglobin concentration than those at mid-trimester (p = 0.008); (3) labor at term was not associated with a significant difference in the median AF fetal hemoglobin concentration; (4) the median AF fetal hemoglobin concentration was not significantly different among the three PTL groups or between the PPROM groups; (5) women with PTL and IAI had a lower AF fetal hemoglobin percentage of the total hemoglobin than those without IAI who delivered preterm (p = 0.03) or at term (p < 0.001); (6) The median AF fetal hemoglobin concentration was higher in pregnancies complicated with PTL or PPROM than in women at term (p < 0.001 for all comparison).
  
  
  CONCLUSIONS
  (1) The concentration of immunoreactive AF fetal hemoglobin increases with gestational age; (2) the median AF fetal hemoglobin concentration is higher in pregnancies complicated with PTL or PPROM than in term pregnancies; (3) among women with PTL or PPROM, the AF fetal hemoglobin concentrations were not associated with IAI; (4) however, women with PTL and IAI had a lower percentage of AF fetal hemoglobin of the total hemoglobin than those without IAI, suggesting different mechanisms of disease.
authors.affiliation: Perinatology Research Branch, NICHD, NIH, DHHS, Wayne State University, Hutzel Women's Hospital, 3990 John R, Box 4, Detroit, MI 48201, USA. evaisbuch@med.wayne.edu
authors.forename: Edi
authors.initials: E
authors.lastname: Vaisbuch
authors.forename: Juan Pedro
authors.initials: JP
authors.lastname: Kusanovic
authors.forename: Offer
authors.initials: O
authors.lastname: Erez
authors.forename: Shali
authors.initials: S
authors.lastname: Mazaki-Tovi
authors.forename: Francesca
authors.initials: F
authors.lastname: Gotsch
authors.forename: Chong Jai
authors.initials: CJ
authors.lastname: Kim
authors.forename: Jung-Sun
authors.initials: JS
authors.lastname: Kim
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
authors.forename: Sam
authors.initials: S
authors.lastname: Edwin
authors.forename: Nandor Gabor
authors.initials: NG
authors.lastname: Than
authors.forename: Chia-Ling
authors.initials: CL
authors.lastname: Nhan-Chang
authors.forename: Moshe
authors.initials: M
authors.lastname: Mazor
authors.forename: Pooja
authors.initials: P
authors.lastname: Mittal
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000737:chemistry* / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis* / Q000378:metabolism; D005322:Premature Rupture of Fetal Membranes / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000378:metabolism*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000378:metabolism; D047929:Term Birth / Q000378:metabolism; D055815:Young Adult
chemical_list: D005319:Fetal Hemoglobin