title: Breastfeeding, genetic, obstetric and other risk factors associated with mother-to-child transmission of HIV-1 in Sao Paulo State, Brazil. Sao Paulo Collaborative Study for Vertical Transmission of HIV-1.
abstract: OBJECTIVE
  To evaluate the effect of maternal, obstetric, neonatal and post-natal factors on the risk of vertical transmission of HIV-1.
  
  
  METHODS
  Multicentre retrospective cohort study.
  
  
  METHODS
  Obstetric and paediatric clinics in four cities in Sao Paulo State, Brazil.
  
  
  RESULTS
  Child's HIV-1 infection status.
  
  
  METHODS
  Data were collected by standardized record abstraction and interview on 553 children born to women identified as HIV-1-infected before or at delivery. Paediatric infection was determined by immunoglobulin G anti-HIV-1 tests at age 18 months or by AIDS diagnosis at any age. Multivariate logistic regression was used to assess the effect of potential risk factors on vertical transmission of HIV-1.
  
  
  RESULTS
  HIV-1 infection status was determined for 434 children (follow-up rate of 78%); 69 were classified as HIV-1-infected [transmission risk, 16%; 95% confidence interval (CI), 13-20%]. In multivariate analysis, advanced maternal HIV-1 disease [odds ratio (OR), 4.5; 95% CI, 2.1-9.5], ever breastfed (OR, 2.2; 95% CI, 1.2-4.2), child's negative Rhesus blood group (OR, 2.5; 95% CI, 1.2-5.5), third trimester amniocentesis (OR, 4.1; 95% CI, 1.2-13.5) and black racial group (OR, 0.3; 95% CI, 0.1-0.9) were independently and significantly associated with mother-to-child transmission of HIV-1. Transmission was increased marginally with prematurity, more than 10 lifetime sexual partners and prolonged duration of membrane rupture. No association was found between child's HIV-1 infection and mode of delivery or serological evidence of syphilis during pregnancy.
  
  
  CONCLUSIONS
  These findings support the importance of severity of maternal HIV-1 disease in the risk of vertical transmission of HIV-1, indicate measures to reduce transmission by avoiding amniocentesis and breastfeeding and suggest that race and Rhesus blood type may be markers for genetic susceptibility to infection.
authors.affiliation: London School of Hygiene and Tropical Medicine, UK.
authors.forename: B H
authors.initials: BH
authors.lastname: Tess
authors.forename: L C
authors.initials: LC
authors.lastname: Rodrigues
authors.forename: M L
authors.initials: ML
authors.lastname: Newell
authors.forename: D T
authors.initials: DT
authors.lastname: Dunn
authors.forename: T D
authors.initials: TD
authors.lastname: Lago
mesh_terms: D000428:Alcohol Drinking; D000649:Amniocentesis; D001938:Brazil / Q000453:epidemiology; D001942:Breast Feeding; D002585:Cesarean Section; D004198:Disease Susceptibility; D005260:Female; D005865:Gestational Age; D015658:HIV Infections / Q000517:prevention & control / Q000635:transmission*; D015497:HIV-1; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D008423:Maternal Age; D015999:Multivariate Analysis; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D044469:Racial Groups; D012204:Rh-Hr Blood-Group System; D012307:Risk Factors; D012725:Sexual Behavior
chemical_list: D012204:Rh-Hr Blood-Group System