Early Blood Tests Predict Pregnancy Complications

Research indicates that routine blood tests conducted years before a woman becomes pregnant may be able to identify an increased risk of developing high blood pressure and pre-eclampsia during pregnancy.

A study from Karolinska Institutet, published in JAMA Network Open, found that small abnormalities in inflammation, blood lipids, and blood sugar several years prior to pregnancy are linked to these complications. The findings suggest that health markers already utilized in standard healthcare could be repurposed to identify at-risk women long before they conceive, potentially allowing for earlier preventive measures in antenatal care.

Predicting Risks Years Before Conception

The research utilized the AMORIS database, tracking just over 35,000 women in Stockholm, Sweden, who were expecting their first child. The researchers analyzed health examinations and blood tests performed approximately four to six years before the women became pregnant.

These early examinations measured specific markers, including blood lipids, blood sugar, and indicators of low-grade inflammation. By following these women through national registers, researchers were able to correlate these early metabolic markers with pregnancy outcomes.

The study found that 5.5 per cent of the women in the group developed pre-eclampsia or high blood pressure during their pregnancy. The risk varied significantly based on the woman’s metabolic health years earlier.

Among women who exhibited metabolic disturbances prior to pregnancy, between 5.5 per cent and 12.8 per cent developed the complications, depending on which specific marker was elevated. In contrast, only 4.1 per cent to 5.3 per cent of women with levels within the normal range were affected.

Our study shows that early blood tests, which are already used in healthcare in other contexts, can help identify women at risk long before they become pregnant. In the long term, this could open up new opportunities to prevent pregnancy complications.

Karin Leander, senior lecturer and associate professor at the Institute of Environmental Medicine, Karolinska Institutet

Currently, risk assessments for pregnancy complications are primarily based on data collected after a woman has already become pregnant. The Karolinska Institutet research suggests a shift toward identifying vulnerabilities years in advance.

The Impact of Pre-eclampsia

High blood pressure during pregnancy is a relatively common occurrence and often serves as an early warning sign of pre-eclampsia. This condition can be fatal and affects up to 1 in 12 pregnancies.

Beyond the immediate risks to the pregnancy, women who experience pre-eclampsia face a higher lifetime risk of death and cardiovascular disease.

Alternative Early Detection Methods

While the Karolinska study focuses on markers years before pregnancy, other research has focused on identifying the condition during the first and second trimesters. An international research team detailed in Nature developed a blood test designed to predict pre-eclampsia risk before clinical signs appear by analyzing cell-free (cf) RNA molecules in the maternal bloodstream.

This study analyzed cfRNA signatures from more than 1,800 women of various body masses, ethnicities, and ages. Blood samples were collected while the women were between 16 and 27 weeks of gestation.

By comparing the plasma of 72 women who developed pre-eclampsia against 452 women who did not, the team identified seven genes with expression levels that consistently differentiated the disease from a normal pregnancy. Four of these genes had already been linked to placental development or pre-eclampsia.

The researchers used a mathematical model to estimate the probability of the condition, which demonstrated a sensitivity of 75 per cent, meaning it successfully identified three-quarters of the eventual pre-eclampsia cases.

Together, these two different research approaches—one focusing on long-term metabolic health before conception and the other on genetic markers during early gestation—point toward a future of more precise, early-warning systems for pregnancy complications.