Low-Dose Aspirin for the Prevention of Preeclampsia

The effectiveness of low-dose aspirin for the prevention of hypertensive disorders of pregnancy in a sub-Saharan Africa Country: A randomized clinical trial

OBJECTIVE

To evaluate whether a daily dose of low-dose aspirin (LDA) can prevent hypertensive disorders of pregnancy (HDP), including preeclampsia, among pregnant women in a South African cohort, and to assess its impact on related maternal and fetal outcomes, such as preterm birth and neonatal complications.

STUDY DESIGN

This single-center, open-label, parallel-group randomized controlled trial (RCT) was conducted at a regional hospital in Durban, KwaZulu-Natal, South Africa, from May 2021 to March 2024. A total of 423 pregnant women, aged 18 years or older with singleton pregnancies between 12 and 20 weeks of gestation, were randomized to receive either 162 mg of LDA daily or standard care. The primary outcome was the incidence of HDP, while secondary outcomes included early-onset preeclampsia (EOPE), preterm birth, low birth weight (LBW), and neonatal death. Data analysis used relative risk (RR) and 95 % confidence intervals (CIs).

RESULTS

Of the 423 women, 209 were in the LDA group and 214 in the control group. The incidence of HDP was significantly lower in the LDA group (6.2 % vs. 25.2 %; RR = 0.25, 95 % CI [0.14-0.44], p < 0.001), corresponding to a 75 % reduction in HDP risk, with an absolute risk reduction (ARR) of 19 % and a number needed to treat (NNT) of 5.3. EOPE was reduced (2.4 % vs. 14.0 %; RR = 0.17, 95 % CI [0.07-0.41], p < 0.001), as was preterm birth (6.7 % vs. 26.2 %; RR = 0.26, 95 % CI [0.15-0.45], p < 0.001). There were no significant differences for LBW or neonatal death. Sensitivity analysis confirmed the importance of initiating LDA before 16 weeks, showing continued reductions in HDP incidence with early initiation.

CONCLUSION

LDA significantly reduces the risk of HDP, EOPE, and preterm birth, particularly when initiated before 16 weeks of gestation. These findings support the use of LDA for preventing hypertensive disorders of pregnancy in low-resource settings and underscore the value of early intervention for improved maternal and fetal outcomes.

An Examination of the Effect of Aspirin and Salicylic Acid on Soluble Fms-like Tyrosine Kinase-1 Release from Human Placental Trophoblasts

Low-dose aspirin (LDA) is efficacious in preventing preeclampsia, but its mechanism of action is unclear. Conflicting evidence suggests that it may inhibit placental trophoblast release of soluble fms-like tyrosine kinase-1 (sFlt1), a key mediator of preeclampsia. We examined whether, and at what concentrations, aspirin and its principal metabolite, salicylic acid, modulate sFlt1 release and/or expression in trophoblasts. Human trophoblast lines BeWo and HTR-8/SVneo were cultured; BeWo cells were also treated with 1% oxygen vs. normoxia to mimic hypoxia in preeclamptic placentas. Cells were treated with aspirin or salicylic acid vs. vehicle for 24 h at concentrations relevant to LDA and at higher concentrations. Protein concentrations (ELISA) and mRNA expression (RT-PCR) of sFlt1 were determined. Under normoxia, LDA-relevant concentrations of aspirin (10-50 µmol/L) or salicylic acid (20-100 µmol/L) had no significant effect on sFlt1 protein release or mRNA expression in BeWo cells. However, inhibition was observed at higher concentrations (1 mmol/L for aspirin and ≥200 μmol/L for salicylic acid). Hypoxia enhanced sFlt1 protein release and mRNA expression in BeWo cells, but these responses were not significantly affected by either aspirin or salicylic acid at LDA concentrations. Similarly, neither drug altered sFlt1 protein secretion or mRNA expression in normoxic HTR-8/SVneo cells at LDA concentrations. We suggest that direct modulation of trophoblast release or expression of sFlt1 is unlikely to be a mechanism underlying the clinical efficacy of LDA in preeclampsia.

A cross-sectional examination of the early-onset hypertensive disorders of pregnancy and industrial emissions of toxic metals using Kentucky birth records, 2008-2017

This cross-sectional study assessed geospatial patterns of early-onset hypertensive disorders of pregnancy (eHDP) in primiparous mothers and exposure to industrial emissions using geocoded residential information from Kentucky live (N = 210,804) and still (N = 1,247) birth records (2008-2017) and census block group estimates of aerosol concentrations of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), selenium (Se), and zinc (Zi) from the Risk Screening Environmental Indicators (RSEI) model. A latent class analysis allowed for the identification of four district exposure classes-As, Cd, and Pb (12.6%); Se and Zi (21.4%); Pb and Cr (8%); and low or no exposures (57.9%). Women classified as having a high probability of exposure to both Pb and Cr had a statistically significantly greater prevalence of eHDP after adjusting for demographic factors (aPR = 1.22, 95% CI: 1.04, 1.44) relative to those with low or no exposure. Our findings contribute to the emerging literature on the association of metal exposures with pregnancy outcomes.