title: Prognostic significance of unexplained elevated amniotic fluid alpha-fetoprotein.
abstract: OBJECTIVE
  To compare the prognostic values of unexplained elevated amniotic fluid alpha-fetoprotein (AF AFP > or = 2.0 multiples of the median [MoM]) and unexplained elevated maternal serum alpha-fetoprotein (MSAFP > or = 2.5 MoM).
  
  
  METHODS
  We accessed a data base containing the results of MSAFP screening tests, genetic amniocenteses, and pregnancy outcome data on all women undergoing second-trimester genetic amniocentesis from October 1988 through August 1994. After excluding all patients whose elevated AFP levels had any identifiable cause (positive AF acetylcholinesterase, AF blood contamination, fetal malformation or aneuploidy, multiple gestation, etc), 5743 cases were analyzed. Relative risks (RR) for selected pregnancy complications were determined.
  
  
  RESULTS
  Elevated MSAFP, with any AF AFP, was associated with fetal growth restriction (RR 2.5, 95% confidence interval [CI] 1.4-4.4), stillbirth (RR 3.5, 95% CI 1.4-8.3), preeclampsia (RR 2.8, 95% CI 1.1-7.0), and preterm delivery (RR 2.8, 95% CI 2.3-3.4). Elevated AF AFP, with any MSAFP, was associated with preeclampsia (RR 4.4, 95% CI 2.0-10.0) and preterm delivery (RR 1.7, 95% CI 1.3-2.4). Elevation of both AF AFP and MSAFP was associated with preterm delivery (RR 4.0, 95% CI 2.8-5.7). When elevated AF AFP was found in association with a normal MSAFP, the RR to develop preeclampsia was 4.6 (95% CI 1.9-11.2).
  
  
  CONCLUSIONS
  Maternal serum alpha-fetoprotein is a better predictor of late pregnancy complications than AF AFP. However, unexplained elevated AF AFP appears to be especially predictive of preeclampsia.
authors.affiliation: Department of Obstetrics and Gynecology, University of Alabama at Birmingham, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Wenstrom
authors.forename: J
authors.initials: J
authors.lastname: Owen
authors.forename: R O
authors.initials: RO
authors.lastname: Davis
authors.forename: C G
authors.initials: CG
authors.lastname: Brumfield
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry*; D005260:Female; D006801:Humans; D015994:Incidence; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000378:metabolism; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011379:Prognosis; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D000509:alpha-Fetoproteins