title: Pregnancy Associated Plasma Protein-A and Placental Growth Factor in a Sub-Saharan African Population: A Nested Cross-Sectional Study.
abstract: BACKGROUND
  Baseline distributions of pregnancy disorders' biomarkers PlGF and PAPP-A levels are primarily based on Western European populations of Caucasian ethnicity. Differences in PAPP-A and PlGF concentrations by ethnicity have been observed, with increased levels in Afro-Caribbean, East Asian, and South Asian women. Baseline concentrations of sub-Saharan African women have not been evaluated.
  
  
  OBJECTIVE
  To investigate PlGF and PAPP-A in a sub-Saharan African population and assess the performance of existing reference values of PAPP-A and PlGF.
  
  
  METHODS
  A nested cross-sectional study was conducted in two public hospitals in Accra, Ghana. Out of the original 1010 women enrolled in the cohort, 398 participants were eligible for inclusion with a normotensive singleton gestation and serum samples taken between 56-97 days of pregnancy. PAPP-A and PlGF concentrations were measured with an automated immunoassay. Multiple of the median (MoM) values corrected for gestation and maternal weight for PAPP-A and PlGF were calculated using reference values of a Dutch perinatal screening laboratory based on over 10.000 samples, and PlGF manufacturer reference values, respectively.
  
  
  RESULTS
  The PAPP-A median MoM was 2.34 (interquartile range (IQR) 1.24-3.97). Median PlGF MoM was 1.25 (IQR 0.95-1.80). Median MoM values for PAPP-A and PlGF tended to be slightly different for various Ghanaian ethnic subgroups.
  
  
  CONCLUSIONS
  PAPP-A and PlGF MoM values appear to be substantially higher in a sub-Saharan African population compared to the Caucasian or Afro-Caribbean MoM values previously reported. The difference suggests the need for a specific correction factor for this population to avoid underestimation of risk for fetal aneuploidies or placental disorders when using PAPP-A and PlGF MoM for screening purposes.
authors.affiliation: Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Joyce L
authors.identifier: http://orcid.org/0000-0001-7048-3245
authors.initials: JL
authors.lastname: Browne
authors.affiliation: Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.|Division of Epidemiology & Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Klipstein-Grobusch
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center Utrecht, The Netherlands.
authors.forename: Maria P H
authors.initials: MP
authors.lastname: Koster
authors.affiliation: Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Dhivya
authors.initials: D
authors.lastname: Ramamoorthy
authors.affiliation: Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.|Ghana Health Service, Greater Accra Regional Health Directorate, Accra, Ghana.
authors.forename: Edward
authors.initials: E
authors.lastname: Antwi
authors.affiliation: Center for Infectious Diseases Research, Diagnostics and Screening (IDS), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Idder
authors.initials: I
authors.lastname: Belmouden
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center Utrecht, The Netherlands.
authors.forename: Arie
authors.initials: A
authors.lastname: Franx
authors.affiliation: Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Diederick E
authors.initials: DE
authors.lastname: Grobbee
authors.affiliation: Center for Infectious Diseases Research, Diagnostics and Screening (IDS), National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
authors.forename: Peter C J I
authors.initials: PC
authors.lastname: Schielen
mesh_terms: D000293:Adolescent; D000328:Adult; D017954:Africa South of the Sahara; D015415:Biomarkers / Q000097:blood; D044383:Black People; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007118:Immunoassay; D010920:Placenta / Q000502:physiology; D000072483:Placenta Growth Factor / Q000097:blood*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis*; D011261:Pregnancy Trimester, First / Q000097:blood*; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011296:Prenatal Diagnosis / Q000379:methods*; D012016:Reference Values; D055815:Young Adult
chemical_list: D015415:Biomarkers; D000072483:Placenta Growth Factor; D011266:Pregnancy-Associated Plasma Protein-A