title: Twin pregnancy as a risk factor for mother-to-child transmission of HIV-1: trends over 20 years.
abstract: OBJECTIVE
  We investigated whether twin pregnancies were at increased risk of mother-to-child HIV-1 transmission (MTCT), in comparison with singletons.
  
  
  METHODS
  Among HIV-1 infected women enrolled in the French Perinatal HIV Cohort (n = 9262), we studied the association between twin deliveries and MTCT rate according to three time periods (pre-1994, 1994-1996, 1997-2004) and the effect of birth order. The mother was considered to have transmitted if at least one of the twins was infected. Univariate and multivariate analyses of risk factors for MTCT were performed for deliveries in the periods up to 1996.
  
  
  RESULTS
  Overall, 2.1% (192/9262) of all the deliveries were twins. The rate of prematurity was greater in twins than in singletons (54% and 13%, respectively). Up to 1996 the rate of MTCT of HIV-1 was 28.3% (15/53) in twin pregnancies, versus 13.5% (414/3077) in singletons [odds ratio (OR), 2.5; 95% confidence interval (CI), 1.4-4.7; P = 0.002; adjusted OR, 2.3: 95% CI, 1.1-2.3; P = 0.03). In the period from 1997 to 2003, MTCT was low and did not differ between twins (1.0%) and singletons (1.8%; P = 1.0). Overall, the transmission rate for the first-born child was threefold that for the second-born child (14/164, 8.5% versus 4/164, 2.4%; P = 0.008).
  
  
  CONCLUSIONS
  Twin pregnancies were at increased risk of transmission, but in the era of HAART this risk was reduced for twins, as well as singletons. Management of multiple pregnancies should take into account the risks of premature rupture of the membranes and preterm delivery.
authors: Inserm, U822, IFR69, Le Kremlin-Bicêtre, France.
authors: Claudia Palladino Sili
authors: CP
authors: Scavalli
authors: Laurent
authors: L
authors: Mandelbrot
authors: Alain
authors: A
authors: Berrebi
authors: Agnès
authors: A
authors: Batallan
authors: Ludovic
authors: L
authors: Cravello
authors: Emmanuelle
authors: E
authors: Pannier
authors: Karima
authors: K
authors: Hamrene
authors: Nicole
authors: N
authors: Ciraru-Vigneron
authors: Albert
authors: A
authors: Faye
authors: Josiane
authors: J
authors: Warszawski
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use; D001722:Birth Order; D004200:Diseases in Twins / Q000453:epidemiology*; D005260:Female; D005602:France / Q000453:epidemiology; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D018445:Infectious Disease Transmission, Vertical; D007752:Obstetric Labor, Premature; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy / Q000821:virology; D011272:Pregnancy, Multiple; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood; D012307:Risk Factors
chemical_list: D019380:Anti-HIV Agents; D012367:RNA, Viral