title: Resistance to antiretrovirals in HIV-infected pregnant women.
abstract: BACKGROUND
  Antiretrovirals suppress HIV replication and prevent mother-to-child-transmission of HIV (PMTCT). Resistance to antiretrovirals may reduce the efficacy of PMTCT and/or complicate treatment of maternal or infant infection.
  
  
  OBJECTIVE
  To assess resistance to antiretrovirals during pregnancy.
  
  
  METHODS
  Retrospective chart review of 44 pregnancies.
  
  
  RESULTS
  Twenty-two patients were antiretroviral treatment-naïve, 8 were on therapy, and 14 had prior therapy, but were off medication when the genotyping was performed. Major mutations were found in 10 antiretroviral-experienced women, including 5 women with major mutations to 2 classes of drugs (none to 3 classes). Major mutations were most common for lamivudine, nevirapine, zidovudine, stavudine, and abacavir. Three women had significant resistance to zidovudine/lamivudine, a combination recommended in PMTCT guidelines. Despite significant antiretroviral resistance, 6 of 8 women with plasma HIV RNA measured within 4 weeks of delivery achieved <50 copies/mL. All neonates were uninfected. Among 6 women who received antiretrovirals exclusively for PMTCT, there were no remarkable changes of the HIV genotype before and after pregnancy.
  
  
  CONCLUSIONS
  Resistance to antiretrovirals was common in antiretroviral-experienced pregnant women, but not in naïve women. The 14% prevalence of resistance to zidovudine and lamivudine in antiretroviral-experienced women suggests that alternative NRTI are desirable for this group of patients.
authors.affiliation: University of Colorado Denver School of Medicine, Aurora, CO 80045, USA. Adriana.Weinberg@ucdenver.edu
authors.forename: Adriana
authors.initials: A
authors.lastname: Weinberg
authors.forename: Jeri
authors.initials: J
authors.lastname: Forster-Harwood
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: McFarland
authors.forename: Jennifer
authors.initials: J
authors.lastname: Pappas
authors.forename: Jill K
authors.initials: JK
authors.lastname: Davies
authors.forename: Kay
authors.initials: K
authors.lastname: Kinzie
authors.forename: Emily A
authors.initials: EA
authors.lastname: Barr
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Paul
authors.forename: Carol R
authors.initials: CR
authors.lastname: Salbenblatt
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Soda
authors.forename: Anna
authors.initials: A
authors.lastname: Vazquez
authors.forename: Myron J
authors.initials: MJ
authors.lastname: Levin