High Rates of Preterm Birth and Small for Gestational Age in a Cohort of HIV Infected Women in Canada: Role of Ritonavir Boosted Regimens?
The rate of preterm delivery (PTD) among HIV positive women and the possible association with the use of Antiretroviral therapy (ART) during pregnancy remains a subject of debate. The primary objective of this study is to determine risk factors for PTD and Small for Gestational Age (SGA) among HIV infected pregnant women in Canada.
Mother-infant pairs were identified from the Canadian Perinatal HIV Surveillance Program, an active surveillance system that captures data on perinatal HIV exposure annually from 22 sites in Canada. PTD was defined as delivery at less than 37 weeks gestational age (GA), and SGA as weight less than 10th percentile for age. Multivariable logistic regression was used to adjust for available known risk factors for PTD, and accounted for the dependence between multiple pregnancies of the same woman.
Between 1987 and 2013, the overall incidence of PTD was 16.26% (427 out of 2626 births), compared to a PTD rate in Canada of 8% over this time period. The majority (13.52%) were late pre-term infants (32-36 weeks GA), The overall incidence of SGA was 20.48%. Significant risk factors for PTD on univariate analysis included detectable vs. undetectable viral load (VL) (OR: 1.62, p=0.008), aboriginal vs. white race (OR 1.65, p=0.002), HIV acquisition risk factor (intravenous drug use vs. heterosexual transmission, OR 2.17, p<0.001), and no ART vs. any ART (OR 1.58, p=0.004). Among ART treated women, there was an increased risk of PTD among those treated with boosted vs. unboosted PIs (OR 1.58, p=0.004), and more specifically, among women starting boosted PIs at 21-27 weeks as compared to 13-20 weeks (OR 3.17 p=0.01). In the multivariable analysis adjusting for maternal race, HIV acquisition risk factor and ART start time, the risk of PTD associated with the use of boosted PIs remained statistically significant (aOR 1.48, p=0.01). There was no association between SGA and ART exposure.
Our results show that HIV positive pregnant women have high rates of PTD and SGA. A modifiable risk factor may be the type of ART regimen used, as an increased risk of PTD was seen in association with the use of ritonavir boosted regimens. Further study is needed to identify the safest ART regimens to be used in pregnancy.
T. Lee, None
J. Singer, None
L. J. Sauve, None
L. M. Samson, None
D. Money, None