# Effect of aspirin on maternal hemodynamics in Chinese women at high risk for preterm pre‐eclampsia: longitudinal study

## TL;DR

This study finds that high-risk Chinese women for preterm pre-eclampsia have abnormal blood pressure and heart function during pregnancy, and aspirin does not significantly improve these issues.

## Contribution

The study longitudinally evaluates maternal hemodynamics in high-risk Chinese women for preterm pre-eclampsia and assesses the effect of aspirin prophylaxis.

## Key findings

- High-risk women showed higher blood pressure and vascular resistance and lower cardiac output compared to low-risk women.
- Aspirin prophylaxis did not significantly improve hemodynamic parameters in high-risk women.
- Hemodynamic differences in high-risk women were evident as early as the first trimester.

## Abstract

To compare the maternal hemodynamics of Chinese women at low and at high risk for preterm pre‐eclampsia (PE) and assess the differences in hemodynamic parameters between high‐risk women with or without prophylactic aspirin.

This was a prospective longitudinal case–control study of 857 Chinese women with a singleton pregnancy who participated in the first‐trimester screen‐and‐prevent program for PE at the Prince of Wales Hospital, Hong Kong SAR, China, between February 2020 and March 2023. The risk of developing preterm PE (delivery before 37 weeks) was determined using the Fetal Medicine Foundation combined test (maternal factors combined with mean arterial pressure (MAP), uterine artery pulsatility index and placental growth factor). The study population comprised three groups of women: (1) women at high risk (adjusted risk ≥ 1:100) for preterm PE who received 100 mg or 160 mg of aspirin according to maternal weight (< 40 kg or ≥ 40 kg, respectively), starting before 16 weeks' gestation until 36 weeks' gestation, until delivery or until PE was diagnosed if before 36 weeks; (2) women at high risk for preterm PE who did not receive aspirin; and (3) women at low risk (adjusted risk < 1:100) for preterm PE who were matched 1:1 to high‐risk women, according to maternal age, weight and date of the scan. MAP was measured using a device validated for use in pregnancy, and heart rate (HR), stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were evaluated using two‐dimensional transthoracic echocardiography at 12 + 0 to 15 + 6 weeks, 20 + 0 to 24 + 6 weeks and 30 + 0 to 37 + 6 weeks' gestation. Log10 transformation was applied to fit the data to a Gaussian distribution. An adjusted multilevel linear mixed‐effects analysis was performed to compare the longitudinal changes of maternal hemodynamics across gestation between the three study groups.

This study comprised 389 women at low risk of preterm PE, 379 women at high risk of preterm PE who received aspirin and 89 women at high risk who did not receive aspirin. There was no significant difference in the estimated marginal mean (EMmean) of log10 HR across gestation among the three study groups. Compared with the low‐risk group, both high‐risk groups (with and without aspirin) exhibited consistently higher EMmean of log10 MAP and log10 SVR, and lower EMmean of log10 CO and log10 SV throughout gestation (all P < 0.001). Although maternal hemodynamic trajectories differed across the EMmean of log10 SV, CO, MAP and SVR between high‐risk women with aspirin and those without, there were no significant differences in these parameters between the two high‐risk groups.

This study highlights the significant differences in maternal hemodynamic adaptation during pregnancy between Chinese women at high risk and those at low risk for preterm PE. Compared with low‐risk women, high‐risk women exhibited increased MAP and SVR, along with reduced SV and CO as early as the first trimester, and these alterations persisted throughout gestation. Notably, aspirin prophylaxis showed a limited effect on improving maternal hemodynamics in women at high risk for preterm PE, highlighting the need for alternative strategies to address the hemodynamic maladaptation in high‐risk women. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.