Early blood tests could help identify women at risk long before pregnancy
Long before a woman carries a child, her blood may already be telling a story about the risks ahead. A Swedish research team has found that routine metabolic measurements taken four to six years before conception — glucose, lipids, inflammation — carry quiet signals of who will later face dangerously elevated blood pressure in pregnancy. The discovery, drawn from more than 35,000 first-time mothers in Stockholm, does not introduce new tests but invites medicine to listen more carefully to ones it already performs.
- Preeclampsia strikes roughly one in eighteen pregnant women in this cohort and can escalate to life-threatening crisis with little warning — the urgency to predict it earlier is real.
- Women with even modest metabolic abnormalities years before conception faced nearly double the complication rate of those with normal readings, a gap that demands clinical attention.
- The current system waits until after conception to assess risk, leaving a years-long window of potential intervention completely unused.
- Researchers at Karolinska Institutet argue that existing routine bloodwork — already drawn for other purposes — could be repurposed to counsel at-risk women on lifestyle changes before pregnancy begins.
- The study is observational and cannot yet prove causation, but its scale and consistency are pushing the field toward rethinking what 'borderline normal' results actually mean for women of childbearing age.
A research team at Karolinska Institutet has uncovered something quietly significant in ordinary blood tests: drawn four to six years before pregnancy, routine measurements of glucose, lipids, and inflammation can predict which women will later develop high blood pressure or preeclampsia. The finding, published in JAMA Network Open, draws on health records from more than 35,000 first-time mothers in Stockholm whose pre-pregnancy bloodwork was compared against their eventual pregnancy outcomes.
The numbers are modest but meaningful. Among women whose early results showed metabolic irregularities, between 5.5 and 12.8 percent went on to develop pregnancy-related hypertension or preeclampsia — compared to just 4.1 to 5.3 percent among those with normal readings. The markers in question — LDL cholesterol, triglycerides, apolipoprotein B, the inflammatory protein haptoglobin, and a glucose-metabolism index — are already standard in routine healthcare. The insight is not that new tests are needed, but that existing ones are being underread.
Lead researcher Karin Leander is direct about the practical implication: women of childbearing age could be identified as higher-risk years before conception, giving clinicians and patients time to act — through dietary change, exercise, weight management, or closer future monitoring. This stands in contrast to current practice, where risk assessment begins only after conception, leaving little runway for prevention.
The team is careful to note the study's observational limits — correlation is established, causation is not yet proven. But the findings open a wider question: if these metabolic signals appear years before pregnancy, they may also speak to a woman's long-term cardiovascular health, independent of whether she ever develops preeclampsia. The next phase of research will explore whether the same markers predict gestational diabetes and preterm birth, and what they mean for women's health across decades — not just trimesters.
A Swedish research team has found that ordinary blood tests taken years before a woman becomes pregnant can signal who will later develop dangerously high blood pressure during pregnancy or preeclampsia. The discovery, published in JAMA Network Open, rests on data from more than 35,000 first-time mothers in Stockholm whose health was tracked from routine examinations four to six years before conception through their pregnancies.
The researchers measured three things in those early blood samples: glucose levels, blood lipids, and markers of low-grade inflammation. What they found was straightforward but consequential: women whose results showed even modest abnormalities in these measures faced a substantially higher risk of complications later. Among women with elevated metabolic markers, between 5.5 and 12.8 percent developed high blood pressure or preeclampsia during pregnancy. By contrast, only 4.1 to 5.3 percent of women with normal readings experienced these conditions. Overall, 5.5 percent of the entire cohort developed one of these complications.
Karin Leander, who led the work at Karolinska Institutet's Institute of Environmental Medicine, emphasizes that the blood tests used in this study are already routine in healthcare—they measure LDL cholesterol, triglycerides, apolipoprotein B, the inflammatory marker haptoglobin, and what researchers call the TyG index, which reflects glucose metabolism. The insight is not that these tests are new, but that they can be repurposed. "Early blood tests, which are already used in health care in other contexts, can help identify women at risk long before they become pregnant," Leander says. The implication is practical: doctors could use these existing measurements to counsel women of childbearing age about lifestyle changes or closer monitoring, potentially preventing or reducing the severity of pregnancy complications.
Currently, pregnancy risk assessment happens after conception. Obstetricians monitor blood pressure at every antenatal visit, watching for the sudden elevation that signals preeclampsia—a condition that can turn dangerous quickly if left unchecked. This study suggests that window could open much wider. By identifying at-risk women years in advance, there may be time for intervention: dietary changes, exercise, weight management, or other preventive strategies that could alter the trajectory.
The researchers are careful about what their findings do and do not prove. This was an observational study, meaning they tracked what happened but cannot definitively say that the metabolic abnormalities caused the pregnancy complications. The biology of pregnancy-related high blood pressure remains incompletely understood. Leander notes that the increased risk may begin at levels currently considered normal—a finding that could reshape how clinicians interpret borderline results.
The next phase of research will test whether these same markers predict other pregnancy complications like gestational diabetes and preterm birth. The team also plans to examine whether women with these early abnormalities face elevated cardiovascular risk later in life, independent of pregnancy. That question points toward a larger possibility: that the blood tests reveal something about a woman's metabolic health that matters not just for one pregnancy, but for decades to come.
Citas Notables
Our study shows that early blood tests, which are already used in health care in other contexts, can help identify women at risk long before they become pregnant.— Karin Leander, Karolinska Institutet
Our results suggest that the increased risk may begin even at levels currently considered normal.— Karin Leander
La Conversación del Hearth Otra perspectiva de la historia
So these blood tests existed already. What's actually new here?
The novelty is the connection. Nobody was systematically looking at old bloodwork from years before pregnancy and asking whether it predicted complications. This study did that with 35,000 women. It's a pattern recognition finding.
And the risk increase is real? Five and a half percent to twelve percent is significant?
It depends on how you frame it. If you're a woman with elevated markers, your risk roughly doubles or triples. That's meaningful enough that a doctor would want to know about it. But it's not destiny—most women with abnormal markers still have uncomplicated pregnancies.
Why does this matter now, if doctors are already monitoring blood pressure during pregnancy?
Because you can't prevent what you don't see coming. If you know years in advance that a woman is at higher risk, you have time to address the underlying metabolic issues—diet, exercise, weight. Once you're pregnant and your blood pressure spikes, you're managing a crisis, not preventing one.
Are they saying women should get tested before they plan to get pregnant?
Not quite. They're saying the tests women already get—for their own health, not for pregnancy—could be interpreted differently. A borderline cholesterol or glucose result that seems fine now might actually be a signal worth taking seriously if you're thinking about having children.
What's the catch? Why isn't this already standard practice?
Partly because nobody had made the connection before. But also because this is observational data. They can't prove cause and effect. And the biology is still murky. They don't fully understand why these metabolic markers predict pregnancy complications. That's what they're investigating next.