Preterm preeclampsia screen-and-prevent strategy to launch across HK’s public hospitals after initial success

A screen-and-prevent strategy for preterm preeclampsia (PE), which involves screening in the first trimester and low-dose aspirin prophylaxis for high-risk women in <16–36 weeks of gestation, will be launched in obstetric units of public hospitals across Hong Kong following promising results from a multicentre Asian trial led by the Chinese University of Hong Kong (CUHK) and a pilot programme at the Prince of Wales Hospital (PWH).

The FORECAST trial, conducted between August 2019 and February 2022 in China, Hong Kong, India, Japan, Taiwan, Thailand and Singapore, included 42,897 women with a viable singleton pregnancy at 11–13 weeks of gestation. Results showed that low-dose aspirin prophylaxis significantly reduced adverse outcomes of pregnancy in women at high risk of preterm PE. [Circulation 2024;doi:10.1161/CIRCULATIONAHA.124.06990]

Among high-risk women, low-dose aspirin prophylaxis significantly reduced the incidence of preterm PE by 41 percent (adjusted odds ratio [aOR], 0.59; 95 percent confidence interval [CI], 0.37–0.92), PE with delivery at <34 weeks by 54 percent (aOR, 0.46; 95 percent CI, 0.23–0.93), spontaneous preterm birth at <34 weeks by 55 percent (aOR, 0.45; 95 percent CI, 0.22–0.92), and perinatal death by 64 percent (aOR, 0.34; 95 percent CI, 0.12–0.91) vs no aspirin treatment.

However, the intervention did not significantly reduce the incidence of preterm PE vs no intervention (aOR, 1.59; 95 percent CI, 0.91–2.77).

The stepped wedge cluster randomized trial started with routine antenatal care with no study-related intervention. Subsequently, at regular 6-week intervals, one cluster of participants was randomized to transit from a nonintervention phase to an intervention phase, in which first-trimester screening for preterm PE was performed with the Fetal Medicine Foundation (FMF) triple test comprising maternal characteristics and history, mean arterial pressure, uterine artery pulsatility index, and placental growth factor measurement. Women at high risk of preterm PE (ie, adjusted risk ≥1:100; n=3,543) were given low-dose aspirin (100 mg for body weight ≤40 kg; 160 mg for body weight >40 kg) in <16–36 weeks of gestation, or until delivery or onset of PE before 36 weeks.

“The screen-and-prevent strategy for preterm PE showed a high acceptance rate of 88.04 percent in the study’s diverse group of Asian participants from various ethnic backgrounds,” said Professor Liona Poon of the Department of Obstetrics and Gynaecology, CUHK.

Among high-risk women who took low-dose aspirin, 92.63 percent demonstrated good adherence. The incidence of severe adverse events did not differ between high-risk women who took vs did not take aspirin.

“These findings suggest that the screen-and-prevent strategy for preterm PE can be implemented on a global scale,” commented Poon.

At PWH, a pilot service for PE screening and prevention was launched in April 2022 in collaboration with CUHK. The FMF triple test is combined with Down’s syndrome screening conducted in 11–13 weeks of gestation.

“To date, more than 10,000 pregnant women have been screened, and 1,350 high-risk women have been identified and provided with preventive measures, including low-dose aspirin. The rate of preterm PE has been reduced by 40 percent,” said Dr Isabella Wah of the Department of Obstetrics and Gynaecology, PWH.

The screen-and-prevent service for preterm PE will be expanded to obstetrics units of all public hospitals in Hong Kong in 2025/2026.