title: Association of maternal serum alpha-fetoprotein with persistent placenta previa.
abstract: OBJECTIVE
  To evaluate the relationship between maternal serum alpha-fetoprotein (MSAFP) and the risk of persistent placenta previa.
  
  
  METHODS
  We conducted a retrospective cohort study of singleton pregnancies with sonographic evidence of placenta previa at 15-20 weeks' gestation, between October 1991 and August 2000. Only pregnancies with MSAFP determination at 15-20 weeks' gestation and non-anomalous live-born infants > or =24 weeks' gestation were included. Pregnancies in which Cesarean delivery was performed for placenta previa were considered persistent; this was the primary outcome.
  
  
  RESULTS
  Of 275 women with previa at 15-20 weeks' gestation, 33 (12%) had previa at delivery. Trend analysis revealed a greater likelihood of persistent previa with increasing MSAFP values (p=0.01). Mid-trimester MSAFP <1 multiple of the median (MoM) was associated with a decreased incidence of persistence of 4%, significantly less than the risk at > or =1 MoM (16%; p=0.01).
  
  
  CONCLUSIONS
  There is an association between increasing MSAFP values and greater likelihood of persistent placenta previa. An MSAFP value <1 MoM is associated with a reduction in the risk of persistence of previa to delivery.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center at Dallas, TX 75390-9032, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Koster
authors.forename: J S
authors.initials: JS
authors.lastname: Dashe
authors.forename: D D
authors.initials: DD
authors.lastname: McIntire
authors.forename: R M
authors.initials: RM
authors.lastname: Ramus
mesh_terms: D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D010923:Placenta Previa / Q000097:blood* / Q000000981:diagnostic imaging; D011247:Pregnancy; D011256:Pregnancy Outcome; D014463:Ultrasonography; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D000509:alpha-Fetoproteins