Table 2.

Effectiveness of aspirin on superimposed preeclampsia in regard to gestation age at initiation

Author	Year	Population	Purpose	Design	Main findings	Risk of bias
Sinha, Singh et al [68]	2023	113 pregnant women at high risk	To compare the efficacy of aspirin 150 mg versus 75 mg in the prevention of PE if initiated between 12 and 16 weeks of gestation	Parallel, open-label, randomized control trial	There were five times greater odds of preeclampsia in those who received aspirin 75 mg compared to those who received 150 mg (cOR = 5.341, CI = 1.829–15.594)	Moderate
Ashraf, Ali et al [3]	2024	156 pregnant women with moderate to high risk of PE	To determine the efficacy of aspirin 75 mg vs. 150 mg in moderate and high-risk women if initiated between 11 and 14 weeks	Parallel arm randomized control open-label study	Aspirin 150 mg in moderate and high-risk pregnancies starting at 11–14 weeks was more effective and safer than 75 mg in reducing the incidence of Preeclampsia	Low
Richards, Giorgione et al [58]	2023	2150 pregnant women with chronic hypertension	To determine the efficacy of aspirin 60 mg, 75 mg, 100 mg, 150 mg in the prevention of SIP among women with stage 1 hypertension if initiated before 20 weeks	Systematic review and meta-analysis of nine (three retrospective cohort studies and six randomized trials) studies	Low-dose aspirin prophylaxis did not reduce the odds of pre-eclampsia (OR 0.91, 95% CI 0.64–1.29)	Moderate
Chaemsaithong, Cuenca-Gomez et al [14]	2020	1426 pregnant women at high risk of PE	To determine whether aspirin initiated before 11 weeks’ gestation reduces the rate of preeclampsia	Systematic Review and meta-analysis of 8 randomized controlled trials	Low-dose aspirin initiated at < 11 weeks’ gestation was associated with a no significant reduction in the risk of preeclampsia (relative risk, 0.52; 95% confidence interval, 0.23–1.17, P =.115), gestational hypertension (relative risk, 0.49; 95% confidence interval, 0.20–1.21; P =.121)	Moderate
Shen, Martinez‐Portilla et al [66]	2021	1592 women at risk of PE	To examine the efficacy of aspirin 150 mg in reducing the risk of PE initiated between 11 and 13 weeks	Secondary analysis of data from the ASPRE trial	The use of 150 mg aspirin in women with chronic hypertension did not have a significant effect compared to those without chronic hypertension	Moderate
Banala, Moreno et al. [6]	2020	457 women with chronic hypertension	To assess the impact of the ACOG guideline regarding low-dose aspirin initiated between 12 and 16 weeks of gestation for prevention of SIP In Women With Chronic Hypertension	Retrospective cohort study	No significant decrease in SIP was noted after the implementation of aspirin 81 mg initiated between 12 to 16 weeks of gestation	Moderate
Huai, Lin et al [33]	2021	397 women with stage 1 hypertension	To evaluate the preventive effect of aspirin 100 mg in women with stage 1 hypertension initiated before 16 weeks of gestation	Secondary analysis of data from a randomized controlled trial	The incidence of PE was not significantly reduced in the aspirin group compared to the control group	Moderate
Xiao, Ling et al [77]	2023	266 women at high risk	To assess the efficacy of aspirin 75 mg in preventing PE in high-risk pregnancies	Retrospective chart review	A lower incidence of preeclampsia was observed among women who started taking aspirin before 16 weeks than those who started after 16 weeks (4.69%) vs (17.65%, p = 0.0239). Chronic hypertension was associated with a higher incidence of PE despite taking aspirin (p = 0.0001)	Low