Tests we're already doing can identify risk years before pregnancy
Years before a woman ever conceives, her blood may already be quietly signaling the risks that lie ahead. A Swedish study of more than 35,000 women has found that routine blood tests taken four to six years prior to pregnancy can identify those at two to three times greater risk of developing hypertension or pre-eclampsia — conditions that threaten both mother and child. The discovery, rooted in data already gathered by ordinary healthcare, invites medicine to reconsider where prevention truly begins: not at the first prenatal visit, but long before.
- Pre-eclampsia and pregnancy hypertension affect roughly one in twenty pregnancies and can escalate to life-threatening emergencies with little warning.
- Even modest elevations in cholesterol, triglycerides, inflammation markers, or glucose metabolism indicators years before conception were enough to double or triple a woman's risk.
- The urgency is sharpened by the fact that the predictive tools already exist — these are standard blood panels drawn during routine checkups, not specialized tests requiring new infrastructure.
- Researchers at Karolinska Institutet are now pushing further, investigating whether the same markers forecast gestational diabetes, preterm birth, and long-term cardiovascular disease in women.
- The field is moving toward a model where pregnancy is no longer treated as an isolated health event, but as one chapter in a longer metabolic story that can be read — and redirected — years in advance.
A team at Karolinska Institutet has found that standard blood tests taken four to six years before conception can predict a woman's risk of developing high blood pressure or pre-eclampsia during pregnancy. Drawing on health records from more than 35,000 first-time mothers in Stockholm, researchers cross-referenced routine pre-pregnancy screenings — measuring cholesterol, triglycerides, blood sugar, and inflammation — with outcomes recorded in national health registers.
The results were striking. Women with normal blood work developed hypertension or pre-eclampsia at a rate of four to five percent. But those with even modest elevations in markers like LDL cholesterol, triglycerides, apolipoprotein B, the inflammatory protein haptoglobin, or a glucose index called TyG saw their risk climb to between 5.5 and 12.8 percent — a doubling or tripling detectable years before pregnancy began.
Lead researcher Karin Leander stressed that no new tests are needed. The data is already being collected; it simply hasn't been used this way before. The practical implication is a shift in timing: rather than waiting until conception to assess vulnerability, clinicians could use existing checkup results to begin conversations about prevention far earlier.
The study is observational and stops short of proving causation — the biology of pregnancy-related hypertension remains only partially understood. But the consistency of findings across multiple metabolic markers points toward something real: that subtle disruptions in how the body manages glucose, lipids, and inflammation may quietly lay the groundwork for vascular complications that surface during pregnancy.
Researchers plan to investigate whether these same markers predict gestational diabetes, preterm birth, and future cardiovascular disease — potentially transforming a single blood panel into a window onto a woman's long-term health trajectory, with opportunities for intervention at every stage.
A Swedish research team has discovered that ordinary blood tests performed years before a woman becomes pregnant can flag her risk of developing high blood pressure or pre-eclampsia during pregnancy—conditions that affect roughly one in twenty pregnancies and can turn dangerous quickly if missed.
The study, published in JAMA Network Open and led by researchers at Karolinska Institutet, examined more than 35,000 women in Stockholm who were expecting their first child. Between four and six years before conception, these women had undergone routine health screenings that measured blood sugar, cholesterol, triglycerides, and markers of inflammation. The researchers then tracked what happened during their pregnancies using national health registers.
The numbers tell a clear story. Among women whose blood work fell within normal ranges, about 4 to 5 percent developed high blood pressure or pre-eclampsia. But among those with even modest elevations in certain markers—LDL cholesterol, triglycerides, apolipoprotein B, the inflammatory marker haptoglobin, or a glucose metabolism indicator called the TyG index—the rate climbed to between 5.5 and 12.8 percent. That's roughly a doubling or tripling of risk, detectable years in advance.
Karin Leander, who led the research, emphasized that the blood tests already exist in routine healthcare. "These are tests we're already doing," she explained in essence. "We're simply recognizing that they can serve a second purpose—identifying women at risk long before they become pregnant." The implication is straightforward: instead of waiting until a woman is already pregnant to assess her vulnerability to these complications, doctors could use existing data from regular checkups to start conversations about prevention earlier.
The researchers are careful to note the study's limits. This was observational work, meaning they tracked patterns but cannot prove that the blood abnormalities directly cause pregnancy complications. The underlying biology of pregnancy-related high blood pressure remains incompletely understood. Yet the consistency of the findings across multiple metabolic markers suggests something real is happening—that subtle disturbances in how the body handles glucose and lipids, and how it manages inflammation, may set the stage for vascular problems that emerge during pregnancy.
The next phase of research will test whether these same markers predict other pregnancy complications: gestational diabetes, preterm birth, and whether the metabolic disturbances that show up years before pregnancy also forecast cardiovascular problems later in life. If they do, the implications extend far beyond obstetrics. A single blood test could become a window into a woman's long-term health trajectory, offering opportunities for intervention at multiple points.
For now, the finding suggests a shift in how antenatal care might be organized. Rather than treating pregnancy as an isolated event—monitoring blood pressure only after conception—healthcare systems could use the blood work women already have done during routine checkups to identify those who need closer attention, earlier counseling about lifestyle, or more aggressive monitoring once pregnancy begins. It's a small change in practice that could prevent serious complications in a meaningful number of pregnancies.
Notable Quotes
Early blood tests, which are already used in healthcare in other contexts, can help identify women at risk long before they become pregnant.— Karin Leander, Karolinska Institutet
Routine blood tests could be used as an additional tool to help healthcare professionals assess risk and discuss lifestyle with women of childbearing age.— Karin Leander, Karolinska Institutet
The Hearth Conversation Another angle on the story
So these tests exist already. Doctors are already doing them. Why hasn't anyone noticed this pattern before?
The tests exist, yes, but they're typically done in isolation—a woman gets her cholesterol checked, her blood sugar measured, and that's filed away. Nobody was systematically asking: what happens to these women five years later when they're pregnant? The Swedish researchers had access to a massive database that let them connect the dots backward.
And the risk increase is real? We're not talking about a tiny statistical blip?
No. If you have elevated triglycerides or LDL cholesterol years before pregnancy, your risk of developing high blood pressure during pregnancy roughly doubles or triples. That's substantial. And it's happening at levels doctors currently consider borderline or even normal.
Why does this matter so much? High blood pressure during pregnancy—isn't that something they catch and manage?
They do catch it, usually. But pre-eclampsia can develop fast and become dangerous for both mother and baby. If you know years in advance that a woman is at higher risk, you can start preventive conversations earlier—about diet, exercise, weight, stress. You can monitor her more carefully once she's pregnant. You might prevent the condition entirely.
So this is about shifting from reactive to proactive medicine.
Exactly. Right now, pregnancy care starts when you're already pregnant. This suggests we could start much earlier, using information we already have.
What's the catch? Why isn't this already standard practice?
The researchers themselves say we need to be cautious. This is observational—they saw a pattern, but they can't prove causation. And the biology is complex. We don't fully understand why these metabolic disturbances lead to pregnancy complications. The next step is testing whether interventions actually prevent the problem.