title: Adverse perinatal outcomes are more frequent in pregnancies with a low fetal fraction result on noninvasive prenatal testing.
abstract: OBJECTIVE
  This study aimed to assess risk of an adverse perinatal outcome for women with a low fetal fraction (LFF) result on noninvasive prenatal testing (NIPT).
  
  
  METHODS
  A retrospective cohort study whereby women with an LFF result were compared with women who had a sufficient fetal fraction (SFF) result on NIPT. Inclusion criteria were singleton pregnancies with quantification of fetal fraction and pregnancy outcome information. Primary outcome was a composite of any of the following: miscarriage, fetal demise, neonatal death, preterm birth, pregnancy-associated hypertensive disorder, placental abruption, and low birth weight.
  
  
  RESULTS
  Three hundred forty-eight (94%) women had an SFF result, and 22 (6%) women had an LFF result. The mean gestational age at the time of NIPT was comparable for both groups. Women with an LFF result were more likely to be African American (86% vs 52%; p = 0.007) and have a higher body mass index (BMI) (mean BMI = 37 kg/m(2) vs BMI = 29 kg/m(2) ; p ≤ 0.001) than women with an SFF result. The composite outcome was significantly more common in the LFF group (59.1% vs 29%; p = 0.003). After adjusting for race and BMI, LFF remained independently associated with adverse perinatal outcome with adjusted odds ratio = 2.5 (95% confidence interval 1.01-6.2; p = 0.049).
  
  
  CONCLUSIONS
  Women with an LFF result have an increased likelihood of an adverse pregnancy outcome.
authors.affiliation: Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Iris
authors.initials: I
authors.lastname: Krishna
authors.affiliation: Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Martina
authors.initials: M
authors.lastname: Badell
authors.affiliation: Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Tammy L
authors.initials: TL
authors.lastname: Loucks
authors.affiliation: Department of Gynecology and Obstetrics, Division of Maternal-Fetal Medicine, Emory University School of Medicine, Atlanta, GA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lindsay
authors.affiliation: Maternal-Fetal Medicine, Obstetrix Medical Group of Houston, The Woodlands, TX, USA.
authors.forename: Amber
authors.initials: A
authors.lastname: Samuel
mesh_terms: D000293:Adolescent; D000328:Adult; D002474:Cell-Free System / Q000737:chemistry / Q000378:metabolism; D004247:DNA / Q000302:isolation & purification* / Q000378:metabolism; D005260:Female; D005333:Fetus / Q000737:chemistry* / Q000378:metabolism; D005821:Genetic Techniques / Q000592:standards; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011296:Prenatal Diagnosis / Q000379:methods*; D012189:Retrospective Studies; D013048:Specimen Handling / Q000592:standards; D055815:Young Adult
chemical_list: D004247:DNA