Highpreterm delivery rates associated with initiation of HAART during pregnancy at a London clinic
Polly Clayden, HIV i-Base
HAART use in pregnancy has been associated with preterm delivery (PTD) in some studies but not others.
Graham Taylor and colleagues performed an analysis of pregnancies prospectively recorded at a London clinic between 1995 and 2010.
This review included data for 331 deliveries. The majority of women were black African (78%) and infected through heterosexual intercourse (94%). Their median age was 32 years and median CD4 count 380 cells/mm3. They attended their first antenatal appointment at a median of 13 weeks gestation. Of the group, only eight women took no antiretrovirals prior to delivery and seven took dual NNRTIs.
The remaining women received HAART or prophylaxis, and are described in Table 1.
The investigators reported 45/331 PTD (13.6%) before 37 weeks gestation. Of these, 60% of deliveries were before 34 weeks. They observed no significant difference between women starting new continuous HAART (17.2%) and those already receiving HAART pre-conception (12.6%).
They found a lower rate of PTD among women receiving nevirapine-based HAART to those receiving protease inhibitor-based HAART, which occurred in 16/143 (11.2%) and 23/103 (22.3%) respectively, p=0.02.
They noted that 32 women receiving a short-course of HAART (START) during pregnancy to prevent mother- to-child HIV transmission would have been eligible, if they were willing to deliver by pre-labour caesarean section (PLCS), to receive AZT monotherapy, according to the 2008 BHIVA guidelines. Of these, 23 received PI based START and 39% (9/23) had PTD events compared to 6.2% receiving AZT monotherapy, p=0.0005.
The investigators acknowledged, The role of HAART and PI-based HAART in PTD has been controversial and even in this single centre study confounders abound, despite all women being managed by one team in accordance with BHIVA guidelines.
There was significant variation in CD4 counts and viral loads between women starting HAART in pregnancy and those taking AZT monotherapy or already receiving HAART at conception.
They concluded that their data suggest that PI-based HAART initiated during pregnancy is associated with a significantly increased rate of PTD and that this is influenced by maternal immune status.
They added that further investigation of the mechanism and impact of timing of antiretrovirals to optimise the safe use of this important intervention is overdue.
Table 1. Rates of preterm delivery by treatment/prophylaxis strategy
|Treatment / prophylaxis||N||Median CD4 (Baseline ANC)||Median viral load c/mL||PTD Number (%, 95% CI)|
|AZT monotherapy||65||460||2648||4 (6.2; 2.4-14.8)|
|START||64||360||8930||15 (23.4; 14.7-35.1)|
|New continuous HAART||58||150||23430||11 (19.6; 11.3-31.8)|
|Pre-conception HAART||127||385||49||13 (9.6; 5.9-16.2)|
The association between HAART and PTD continues to be demonstrated, particularly in European cohorts.
The investigators rightly stress that confounders abound and that further investigation into the mechanism and how best to optimise strategies islong overdue.
Taylor G et al. High preterm delivery rates associated with initiation of HAART during pregnancy. 10th International Congress on Drug Therapy in HIV Infection, November 7-11. Glasgow. Poster 158. Published in Journal of the International AIDS Society 2010 13(Suppl 4):P158. http://www.jiasociety.org/content/13/S4/P158