Small abnormalities in blood sugar, blood lipids and inflammation several years before pregnancy are linked to an increased risk of high blood pressure during pregnancy and pre-eclampsia, according to a new study from Karolinska Institutet published in JAMA Network Open. The findings may contribute to earlier risk assessment and preventive measures in antenatal care.
High blood pressure during pregnancy is relatively common and can be an early sign of pre-eclampsia or develop into the condition. Blood pressure is therefore closely monitored at every antenatal appointment to detect changes in good time. Currently, risk assessment is based primarily on data collected after the woman becomes pregnant.
"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," says Karin Leander, senior lecturer and associate professor at the Institute of Environmental Medicine, Karolinska Institutet, who led the research. "In the long term, this could open up new opportunities to prevent pregnancy complications."
Health examinations years earlier
The study is based on the AMORIS database and covers just over 35,000 women in Stockholm, Sweden, who were expecting their first child. About four to six years before pregnancy, the women underwent health examinations and had blood tests that measured, among other things, blood sugar, blood lipids and markers of low-grade inflammation. The women were then followed up in national registers.
In total, 5.5 per cent of the women developed high blood pressure or pre-eclampsia during pregnancy. Depending on which marker was elevated, between 5.5 and 12.8 per cent of women with metabolic disturbances prior to pregnancy were affected, compared with 4.1 to 5.3 per cent among women with levels within the normal range.
Even moderately elevated levels of certain blood lipids (LDL cholesterol, triglycerides and apolipoprotein B), the inflammatory marker haptoglobin, and the so-called TyG index (a marker indicating impaired glucose metabolism) were associated with an increased risk.
"Our results suggest that the increased risk may begin even at levels currently considered normal," explains Karin Leander. "This means that routine blood tests could be used as an additional tool to help healthcare professionals assess risk and discuss lifestyle with women of childbearing age, both before and early in pregnancy."
Monitoring long-term health
The researchers emphasise that the causes behind pregnancy-related high blood pressure are complex and not fully understood. As this was an observational study, the results should be interpreted with caution, and no causal links can be established.
The next step is to investigate whether early abnormalities in blood sugar, blood lipids and inflammation can also predict other complications such as gestational diabetes and preterm birth.
"We will also investigate the association between these markers and women's long-term cardiovascular health," concludes Karin Leander.
