title: [Placental weight percentiles and its relationship with fetal weight according to gestational age in an urban area of Buenos Aires].
abstract: BACKGROUND
  The placental weight (PW) and the rates of their relationship with birth weight (BW) (BW / PW, PW / BW) predict perinatal morbidity and mortality and future health outcomes.
  
  
  OBJECTIVE
  Estimate percentiles of PW and indices by sex and gestational age (GA) corresponding to 867 live born from Sardá Maternity of Buenos Aires and compare with international references.
  
  
  METHODS
  Stillbirth, multiple pregnancy, gestational age <22 and > 42 weeks and PW <100g and > 2500g were excluded. Maternal and fetal characteristics were: age, education, smoking, parity, diabetes, preeclampsia, chorioamnionitis, growth restriction, prematurity and congenital anomalies. Summary statistics and percentiles with the LMS method were calculated. The comparisons were performed using Student t-test, ANOVA and international references.
  
  
  RESULTS
  Average maternal age 24 years , education 10.1 years, 24.5% primiparous, 12.6% smokers, 4.9% had diabetes, 8.7% preeclampsia, 7.9% chorioamnionitis and 13.0% fetal growth restriction; 55.3% of newborns were male, 51.6% preterm, 18.9% small for gestational age and 7.1% malformed. On average BW and GA were 2581g and 35.6 weeks, respectively. High positive correlation between GA with PW and BW/PW, and negative with PW/BW was observed (p <0.001); placental weight and indices were higher in males. Percentiles of PW, BW / PW and PW / BW are depicted. Differences with references ranged from 0.46% -13%, 4.91% -12.1% and 5.81% -14% for PW, BW / PW and PW / BW, respectively.
  
  
  CONCLUSIONS
  Percentiles generated are applicable in research on the relationship of the placenta with perinatal outcomes and health throughout the life cycle.
authors.forename: Carlos
authors.initials: C
authors.lastname: Grandi
authors.forename: Estela
authors.initials: E
authors.lastname: Roman
authors.forename: Jose
authors.initials: J
authors.lastname: Dipierri
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001118:Argentina; D001724:Birth Weight; D004522:Educational Status; D005260:Female; D020567:Fetal Weight; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009929:Organ Size; D010920:Placenta / Q000033:anatomy & histology*; D011247:Pregnancy; D012016:Reference Values; D012189:Retrospective Studies; D014505:Urban Population