title: Increased risk of HIV-1 transmission in pregnancy: a prospective study among African HIV-1-serodiscordant couples.
abstract: BACKGROUND
  Physiologic and behavioral changes during pregnancy may alter HIV-1 susceptibility and infectiousness. Prospective studies exploring pregnancy and HIV-1 acquisition risk in women have found inconsistent results. No study has explored the effect of pregnancy on HIV-1 transmission risk from HIV-1-infected women to male partners.
  
  
  METHODS
  In a prospective study of African HIV-1-serodiscordant couples, we evaluated the relationship between pregnancy and the risk of HIV-1 acquisition among women and HIV-1 transmission from women to men.
  
  
  RESULTS
  Three thousand three hundred and twenty-one HIV-1-serodiscordant couples were enrolled, 1085 (32.7%) with HIV-1 susceptible female partners and 2236 (67.3%) with susceptible male partners. HIV-1 incidence in women was 7.35 versus 3.01 per 100 person-years during pregnant and nonpregnant periods [hazard ratio 2.34, 95% confidence interval (CI) 1.33-4.09]. This effect was attenuated and not statistically significant after adjusting for sexual behavior and other confounding factors (adjusted hazard ratio 1.71, 95% CI 0.93-3.12). HIV-1 incidence in male partners of infected women was 3.46 versus 1.58 per 100 person-years when their partners were pregnant versus not pregnant (hazard ratio 2.31, 95% CI 1.22-4.39). This effect was not attenuated in adjusted analysis (adjusted hazard ratio 2.47, 95% CI 1.26-4.85).
  
  
  CONCLUSIONS
  HIV-1 risk increased two-fold during pregnancy. Elevated risk of HIV-1 acquisition in pregnant women appeared in part to be explained by behavioral and other factors. This is the first study to show that pregnancy increased the risk of female-to-male HIV-1 transmission, which may reflect biological changes of pregnancy that could increase HIV-1 infectiousness.
authors.affiliation: Department of Obstetrics and Gynaecology, Kenyatta National Hospital, Nairobi, Kenya. rwamba@u.washington.edu
authors.forename: Nelly R
authors.initials: NR
authors.lastname: Mugo
authors.forename: Renee
authors.initials: R
authors.lastname: Heffron
authors.forename: Deborah
authors.initials: D
authors.lastname: Donnell
authors.forename: Anna
authors.initials: A
authors.lastname: Wald
authors.forename: Edwin O
authors.initials: EO
authors.lastname: Were
authors.forename: Helen
authors.initials: H
authors.lastname: Rees
authors.forename: Connie
authors.initials: C
authors.lastname: Celum
authors.forename: James N
authors.initials: JN
authors.lastname: Kiarie
authors.forename: Craig R
authors.initials: CR
authors.lastname: Cohen
authors.forename: Kayitesi
authors.initials: K
authors.lastname: Kayintekore
authors.forename: Jared M
authors.initials: JM
authors.lastname: Baeten
mesh_terms: D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D000914:Antibodies, Viral / Q000097:blood*; D016001:Confidence Intervals; D005260:Female; D006679:HIV Seropositivity / Q000453:epidemiology / Q000276:immunology / Q000635:transmission*; D015497:HIV-1 / Q000276:immunology*; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D015994:Incidence; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology / Q000276:immunology* / Q000821:virology*; D011446:Prospective Studies; D012725:Sexual Behavior; D012747:Sexual Partners
chemical_list: D000914:Antibodies, Viral