Cardiovascular complications during pregnancy remain a significant concern for maternal and neonatal health. Pregnant women with high-risk cardiovascular profiles, including those with pre-existing hypertension, diabetes, obesity, or a history of preeclampsia, are at increased risk of developing hypertensive disorders and adverse cardiovascular events during pregnancy (1,2). Preeclampsia, a multisystem disorder characterized by hypertension and proteinuria after 20 weeks of gestation, is one of the leading causes of maternal and fetal morbidity and mortality worldwide (3). The etiology of preeclampsia remains poorly understood, but endothelial dysfunction, oxidative stress, and inflammation are considered key contributors to its development (4,5).

Low-dose aspirin (LDA) has been widely investigated as a potential prophylactic measure to prevent the onset of preeclampsia and other cardiovascular complications in high-risk pregnancies (6). Aspirin exerts its therapeutic effects primarily through the inhibition of platelet aggregation by irreversibly acetylating the cyclooxygenase-1 (COX-1) enzyme, thereby reducing thromboxane A2 production, which is a potent vasoconstrictor and platelet activator (7). Additionally, low-dose aspirin is thought to enhance endothelial function, reduce oxidative stress, and improve placental perfusion, making it a valuable tool in mitigating pregnancy-related cardiovascular complications (8,9).

Several studies have demonstrated the efficacy of low-dose aspirin in reducing the incidence of preeclampsia and associated adverse outcomes when administered early in pregnancy, particularly before 16 weeks of gestation (10,11). The American College of Obstetricians and Gynecologists (ACOG) recommends the use of low-dose aspirin (81 mg daily) for pregnant women at high risk of developing preeclampsia, especially those with previous adverse pregnancy outcomes or chronic hypertension (12).

Despite its widespread use, the cardioprotective effects of low-dose aspirin in pregnant women with high-risk cardiovascular profiles remain a subject of ongoing research. Understanding the precise impact of low-dose aspirin on maternal cardiovascular outcomes, particularly in populations with varying risk factors, is essential for optimizing pregnancy care. This study aims to evaluate the efficacy of low-dose aspirin in improving cardiovascular outcomes and preventing adverse events in pregnant women with high-risk cardiovascular profiles.

Study Design and Participants:

This study was designed as a randomized, double-blind, placebo-controlled clinical trial conducted at a tertiary care hospital. The study population consisted of 120 pregnant women identified as having high-risk cardiovascular profiles based on criteria such as pre-existing hypertension, diabetes mellitus, obesity (BMI ≥ 30 kg/m²), and a history of preeclampsia. Pregnant women aged between 18 and 40 years with singleton pregnancies were included. Exclusion criteria were known hypersensitivity to aspirin, bleeding disorders, and other contraindications to aspirin use.

Randomization and Intervention:

Participants were randomly assigned to one of two groups: Group A (Low-Dose Aspirin Group) and Group B (Placebo Group), with 60 patients in each group. Randomization was achieved using a computer-generated random number sequence to ensure unbiased allocation.

Group A (LDA Group): Participants received low-dose aspirin (75 mg daily) administered orally, starting from 12 weeks of gestation until delivery.

Group B (Placebo Group): Participants received identical-looking placebo tablets daily for the same duration.

Both participants and healthcare providers were blinded to the group allocation throughout the study.

Data Collection and Outcome Measures:

Data were collected through clinical assessments and patient records. The primary outcome measures included:

Incidence of Preeclampsia: Defined as new-onset hypertension (≥140/90 mmHg) and proteinuria (≥0.3 g/24 hours) after 20 weeks of gestation.

Maternal Cardiovascular Events: Including severe hypertension, myocardial infarction, or stroke during pregnancy.

Neonatal Outcomes: Including birth weight, gestational age at delivery, and Apgar scores at 1 and 5 minutes.

Secondary outcomes assessed were systolic and diastolic blood pressure levels, proteinuria levels, and gestational age at delivery. Blood pressure measurements were performed using a calibrated digital sphygmomanometer, and proteinuria was evaluated via 24-hour urine protein collection.

Statistical Analysis:

All statistical analyses were performed using SPSS software (version 25.0). Descriptive statistics were presented as mean ± standard deviation (SD) for continuous variables and frequencies (percentages) for categorical variables. Independent t-tests were used to compare continuous variables between groups, while the Chi-square test was applied for categorical variables. A p-value of less than 0.05 was considered statistically significant.

The study enrolled a total of 120 pregnant women with high-risk cardiovascular profiles, divided equally into two groups: Group A (Low-Dose Aspirin Group) and Group B (Placebo Group). All participants completed the study, and their data were analyzed.

Maternal and Neonatal Outcomes

The incidence of preeclampsia was significantly lower in the low-dose aspirin group compared to the placebo group (Table 1). The occurrence of maternal cardiovascular events was also reduced in Group A. Neonatal outcomes, including birth weight, gestational age at delivery, and Apgar scores, were notably better in the low-dose aspirin group.

Table 1 shows the comparison of maternal and neonatal outcomes between the two groups.

The use of low-dose aspirin was associated with a statistically significant reduction in the incidence of preeclampsia (15% vs. 30%; p = 0.02) and maternal cardiovascular events (3.3% vs. 10%; p = 0.04). Blood pressure control was better in Group A, with significantly lower systolic and diastolic blood pressure levels (p = 0.01 and p = 0.03, respectively).

Additionally, neonatal outcomes were improved in Group A, with higher mean birth weights (3100 ± 400 g vs. 2800 ± 450 g; p = 0.01) and longer gestational age at delivery (38.5 ± 1.2 weeks vs. 37.3 ± 1.5 weeks; p = 0.02). Apgar scores at 5 minutes were also higher in the low-dose aspirin group compared to the placebo group (8.9 ± 0.5 vs. 8.2 ± 0.6; p = 0.03) (Table 1).

The findings of this study indicate that the use of low-dose aspirin in pregnant women with high-risk cardiovascular profiles significantly reduces the incidence of preeclampsia and improves maternal and neonatal outcomes. These results are consistent with previous studies that have demonstrated the efficacy of low-dose aspirin in reducing the risk of preeclampsia and other hypertensive disorders during pregnancy (1,2).

The mechanism by which low-dose aspirin exerts its beneficial effects is primarily through the inhibition of platelet aggregation and improvement of endothelial function (3). Aspirin selectively acetylates cyclooxygenase-1 (COX-1), thereby reducing thromboxane A2 production, a potent vasoconstrictor and promoter of platelet aggregation (4,5). Additionally, aspirin enhances endothelial nitric oxide production, contributing to improved placental blood flow and reduced oxidative stress (6).

The current study demonstrated a statistically significant reduction in the incidence of preeclampsia in the low-dose aspirin group (15%) compared to the placebo group (30%). This finding is in agreement with the results of previous meta-analyses that reported a reduction in preeclampsia incidence with the use of low-dose aspirin, particularly when initiated before 16 weeks of gestation (7,8). Furthermore, maternal cardiovascular events were notably reduced in the low-dose aspirin group, indicating potential cardioprotective effects beyond the prevention of preeclampsia (9).

Improvement in neonatal outcomes, including higher mean birth weights and longer gestational ages, was observed among participants receiving low-dose aspirin. This finding is consistent with the results of previous studies suggesting that aspirin administration may reduce the risk of fetal growth restriction through improved placental perfusion (10,11). A study by Bujold et al. (12) emphasized that early initiation of low-dose aspirin significantly improved pregnancy outcomes in high-risk women, supporting the results of the present study.

Despite the observed benefits, it is important to acknowledge some limitations of this study. The sample size was relatively small, which may limit the generalizability of the findings. Additionally, the study was conducted at a single tertiary care hospital, which may introduce selection bias. Future studies involving larger, multi-centered trials are recommended to validate these findings.

The safety profile of low-dose aspirin remains favorable, with no significant adverse effects reported in the current study. This observation is consistent with previous studies demonstrating the safety of low-dose aspirin in pregnant women, particularly when used at doses between 75 mg and 150 mg per day (13,14). However, there is still ongoing debate regarding the optimal timing for initiating aspirin therapy during pregnancy. Some studies suggest that starting treatment before 16 weeks of gestation offers superior benefits, while others indicate comparable efficacy even when initiated later (15).

Overall, the findings of this study provide further evidence supporting the use of low-dose aspirin as a safe and effective intervention for reducing the incidence of preeclampsia and improving maternal and neonatal outcomes in high-risk pregnancies

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