Pregnancy and pre-eclampsia: is aspirin the answer for everyone?

A new study has ignited the debate over whether every pregnant woman should take low-dose aspirin.

For years, it has been recommended for women at high risk of pre-eclampsia. This dangerous condition can cause high blood pressure and organ damage. The argument for giving it to all pregnant women is straightforward: current screening isn’t perfect, and pre-eclampsia can be hard to predict.

Aspirin is cheap, widely available and generally safe, which makes it tempting to give it to everyone. But medicine rarely works well as a one-size-fits-all solution. The reality is that we still lack tools to identify early in pregnancy when placentas might struggle to support a baby.

Aspirin works by making platelets, the tiny blood cells that form clots, less likely to stick together. In pre-eclampsia, the placenta can trigger inflammation and overactive platelets, reducing blood flow to the baby. By reducing the stickiness of platelets, aspirin helps maintain healthy blood flow between the mother and the baby.

If aspirin is so effective, why not give it to everyone? In heart medicine, healthy older adults were once routinely advised to take daily low-dose aspirin, but several studies have showed that long-term bleeding risks outweigh the benefits and guidance has recently changed. Pregnancy is a much shorter window with treatment lasting only a few months, so the risk of serious bleeding in an otherwise healthy young woman is very low, and the consequences of pre-eclampsia can be severe.

Even so, aspirin doesn’t work the same way for everyone. Standard doses may be too low for women with a higher body mass index or increased blood volume. Absorption can be unpredictable, especially with enteric-coated tablets (which protect the stomach lining) or changes in digestion during pregnancy. And if tablets aren’t taken consistently, the drug can’t do its job.

Right now, doctors decide who should take aspirin mostly based on a woman’s medical history and known risk factors. This simple approach works, but it can miss some women who go on to develop pre-eclampsia, while others are treated just to be safe.

More advanced testing – combining a woman’s medical history with blood pressure checks, blood tests that show how well the placenta is working, and ultrasound scans – can spot more cases. The downside is that these tests need specialist training, extra equipment, and more time, which aren’t always available in everyday care.

The future: better biomarkers

My research looks at platelets and the tiny particles they release, called extracellular vesicles. These microscopic signals reflect how the placenta and maternal environment are interacting, and could identify problems months before symptoms appear. One day, such tests could guide personalised treatment, helping doctors know who really needs aspirin and who may not.

For now, if your doctor has prescribed aspirin in pregnancy, it’s important to continue taking it. It is a safe, effective and evidence-based treatment for women at higher risk of pre-eclampsia. But as science progresses, there’s real potential to move from broad guidelines to personalised care, giving every mother and baby the best chance of a healthy pregnancy.

This article was commissioned in conjunction with Prototypes for Humanity, a global initiative that showcases and accelerates academic innovation to solve social and environmental challenges. The Conversation is the media partner of Prototypes for Humanity 2025.

This article was commissioned in conjunction with Prototypes for Humanity, a global initiative that showcases and accelerates academic innovation to solve social and environmental challenges. The Conversation is the media partner of Prototypes for Humanity 2025. Patricia Maguire works for University College Dublin, Ireland, researching platelets and their role in pre-eclampsia. She receives funding from Enterprise Ireland and Research Ireland.