Background
There are few insights into the immunological predictors of pregnancy outcomes, including preterm delivery (PTD) and small-for-gestational age (SGA), in women living with HIV (WLH).
Methods
We followed ART-eligible pregnant WLH attending primary care in Cape Town from their first antenatal visit through to delivery. C-reactive protein (CRP), interferon gamma-induced protein 10 (IP10), and serum amyloid A (SAA) levels were measured at ≥3 antenatal time points: baseline (<24 weeks [visit 1]), 2 weeks post-ART initiation (if starting ART during pregnancy [visit 2]), 28w [visit 3] and 34w [visit 4]gestation. Group-based trajectory modelling (GBTM) identified distinct biomarker trajectories throughout pregnancy. Modified Poisson regression assessed associations between these trajectories and PTD (<37 weeks) and SGA (<10th percentile for gestational age [GA]), adjusting for age, BMI and ART timing (before vs during pregnancy).
Results
In 505 women (median age 30y; median GA 14w; 23% nulliparous) with a livebirth, 48% (n=241) initiated ART preconception (84% TDF+XTC+EFV, 8% PI-based regimen) and 52% (n=264) initiated during pregnancy (97% TDF+XTC+EFV, 1% PI-based regimens). Median CRP and SAA levels over time did not differ by ART status, but IP-10 levels were higher in women initiating ART during pregnancy than in preconception ART initiators (Fig1a). We identified 4 distinct IP-10 trajectories, with one group (6.5% of women) showing an atypical pattern, with IP-10 levels steadily increasing throughout pregnancy (traj 2) compared to stable (traj 1) or decreasing (traj 3 and 4) (Fig1b). Those with atypical IP-10 trajectories had significantly higher PTD risk (ARR2.08, 95% CI1.03-4.19) than other groups. No associations were observed between CRP and SAA with PTD, and none between the three biomarker trajectories and SGA.
Conclusions
Atypical increases in IP-10 during pregnancy which would indicate increasing inflammation were associated with an increased risk of PTD, but not SGA. Findings suggest IP-10 could be used as a biomarker identifying pregnant women with HIV at higher risk for PTD and inform clinical management.