Time to HIV Suppression with HAART in Pregnancy
J van Schalkwyk1,2, J van Schalkwyk1,2, T Chaworth-Musters1,2, T Chaworth-Musters1,2, E Maan1,2, E Maan1,2, S Gilgoff1,2, S Gilgoff1,2, S Tatum1,2, S Tatum1,2, D Burdge1,2, D Burdge1,2, J Forbes1,2, J Forbes1,2, A Alimenti1,2, A Alimenti1,2, Deborah Money*1,2, and Deborah Money*1,2
1Children's and Women's Hlth Ctr of BC, Vancouver, Canada and 2Univ of British Columbia, Vancouver, Canada
Background: The goal of using HAART in pregnancy is to achieve undetectable
viral load before delivery to reduce the risk of vertical transmission. The
length of treatment required to achieve HIV suppression is critical, but
variable. The physiologic changes in pregnancy do not allow for application of
non-pregnant adult HAART data. Concerns regarding drug toxicity, resistance
development, and ART pharmacokinetics in pregnancy require that the optimal
treatment duration be defined in this special population and time to HIV
suppression be explored.
Methods: A retrospective cohort analysis of HAART-exposed pregnancies
at a tertiary referral center in British Columbia,
was assessed from 1997 to 2005. Demographic data, gestational age at treatment
initiation, and viral suppression (<50 copies/mL
by RNA polymerase chain reaction), prior ART exposure, mean duration to viral
suppression, ART adherence, and type of HAART (non-nucleoside reverse
transcriptase inhibitor [NNRTI- vs protease inhibitor
[PI] -based) in pregnancy were collected.
Results: We evaluated 114 mother-infant pairs (3 sets of twins, each
evaluated as 1 pair): 80% (92 of 114)
achieved viral suppression at delivery, and mother-to-child transmission rate
was 0%. Mean gestational age at treatment initiation was 20.8 weeks (3 to 34 weeks),
and mean gestational age at delivery was 38.5 weeks (range 34 to 41). Median
pre-treatment viral load was 13,400 copies/mL. The mean duration to viral suppression was 58
days (range 3 to 167). Time to suppression did not differ between those treated
with PI (n = 57) vs
NNRTI (n = 34); 58 days (7 to 161) vs 58 days (3 to 167). Time to suppression was 20 days longer in
women previously exposed to ART (51 days (n
= 58) vs 71 days (n
= 34)). By delivery, 22 did not achieve viral suppression. Adherence was good
to excellent in 90.2% who suppressed virus and only 54.5% in those who did not.
Conclusions: HIV suppression was obtained in 80% of HAART-treated women
within a mean of 58 days. The mean duration to suppression did not differ
between women treated with PI- or NNRTI-based HAART. A mean of 20 more days of
therapy was required to achieve suppression in women previously exposed to ART.
This suggests a need for resistance testing in previously ART-exposed pregnant
women. Adherence appeared to contribute to achieving viral suppression. Further
evaluation is required to investigate the factors that lead to suppression
failure in pregnancy.