Table 2.
Associations between HbAS and delivery outcomes
| HbAS (N = 32) | HbAA (N = 814) | OR* (95% CI) | P value† | |
|---|---|---|---|---|
| Real-time PCR testing | ||||
| Plasmodium falciparum positive, n (%) | ||||
| Peripheral blood | 6 (18.8) | 65 (7.7) | 2.53 (1.08–5.94) | 0.03 |
| Placental blood | 5 (15.6) | 103 (12.6) | 1.27 (0.50–3.23) | 0.61 |
| P. falciparum density (N = 76), parasites/μL, median (IQR)‡ | ||||
| Peripheral blood | 2,467 (552–7,736) | 6,118 (2,195–34,241) | NA | 0.14 |
| Placental blood | 5,683 (5,492–10,850) | 7,008 (1,863–22,133) | NA | 0.85 |
| Placental sequestration index§ | 1.21 | 0.99 | NA | 0.37 |
| Histology, n (%) (N = 753) | ||||
| Any evidence of infection | 7 (26.9) | 200 (27.5) | 0.97 (0.40–2.34) | 0.95 |
| Past infection | 3 (11.5) | 90 (12.4) | ||
| Chronic infection | 4 (15.4) | 58 (8) | ||
| Acute infection | 0 | 52 (7.15) | ||
| No infection | 19 (73.1) | 527 (72.5) | ||
| Birth outcomes | ||||
| Low birth weight, n (%) | 3 (9.4) | 92 (11.3) | 0.82 (0.24–2.73) | 0.74 |
| Birth weight, g, mean (SD) | 2,947 (563) | 2,991 (465) | NA | 0.67 |
CI = confidence interval; HbAA = homozygous hemoglobin A; HbAS = heterozygous hemoglobin S; IQR = interquartile range; NA = not applicable; OR = odds ratio; PCR = polymerase chain reaction; SD = standard deviation.
*
Unadjusted OR; reference group for each comparison was women with HbAA.
†
Computed using the Student's t test or Mann–Whitney test for continuous outcomes and χ2 test for categorical outcomes.
‡
Estimated using real-time PCR on only women with concurrent peripheral and placental infection.
§
Defined as the ratio of the density of parasites in placental blood to that in peripheral blood.