Treasure Adenusi , 2025-07-17 14:00:00
Doctors can predict a woman’s risk of hypertension later in life using her blood pressure readings during pregnancy-even if she has ‘normal’ numbers.
In April 2025, a study published in the journal Hypertension found that subtle changes in blood pressure during the first 20 weeks of pregnancy may serve as early warning signs for developing chronic hypertension up to 14 years later.
This enormous observational study, funded by the US federal government’s National Institutes of Health, followed over 170,000 women from their first visit to Kaiser Permanente Northern California prenatal clinic between 2009 and 2024. Researchers used insurance records to track how each woman’s blood pressure and risk of cardiovascular disease changed over time.
It’s well established that pregnancy complications raise a woman’s long-term risk of cardiovascular disease. Doctors know well that conditions like preeclampsia– gestational hypertension, and gestational diabetes can contribute to cardiovascular illness later in life. The researchers had intended to investigate how soon gestational hypertension affects blood pressure. In a surprising twist, they discovered that the physiological adjustments that take place during pregnancy can help doctors to spot signs of trouble to come. Signs that would otherwise go unnoticed.
The study found that even women with no history of these pregnancy-related conditions could face elevated risks. Researchers uncovered a subset of women who showed a distinctive pattern of blood pressure changes during the first 20 weeks of pregnancy. These women were significantly more likely to develop hypertension years after giving birth.
An Early Warning System for Hypertension
Using data from over 170,000 women, the team identified six distinct blood pressure trajectories. Some women had low blood pressure that stayed steady or dropped slightly, while others had blood pressure that started high and stayed high, or rose quickly.
Even though all readings fell within what’s considered a normal range during pregnancy, these patterns told a bigger story.
As the researchers followed the women over time, they found that those with higher or rising blood pressure patterns early in pregnancy were far more likely to develop chronic hypertension years later.
Follow the Numbers
The team tracked each woman’s blood pressure measurements from the first half of pregnancy (up to 20 weeks). They followed each woman’s records for up to 14 years after giving birth, to see who went on to develop chronic hypertension. They also looked at whether the women had experienced any hypertensive disorders during pregnancy like preeclampsia or gestational hypertension. The researchers minimised the chances that other factors could interfere with their observations by ensuring that all of the women entered care before 14 weeks of pregnancy and had no history of high blood pressure or major health conditions like kidney or heart disease.
Researchers grouped women based on how their systolic blood pressure (the top number in a BP reading) changed during the first 20 weeks of pregnancy. This early window is important because it happens before the body naturally lowers blood pressure in the second trimester. By observing this period, the researchers hoped to catch early cardiovascular signals that might not otherwise be detected.
Putting on their data science hats, the researchers used high-powered statistical software to spot patterns in how each woman’s blood pressure changed during her pregnancy and how often that pattern appeared in other women. They grouped the women into six blood pressure pattern groups based on how similar their blood pressure trajectories were. Some had low and stable blood pressure, while others showed a rise early on. They then tested whether the women in each group had similar cardiovascular outcomes – would her blood pressure trajectory in the first 20 weeks predict her risk of hypertension?
Predicting hypertension risk during pregnancy
The higher and steeper the woman’s blood pressure rose during early pregnancy, the greater the risk of developing high blood pressure later in life, no matter if she had pregnancy complications or not.
Women with a history of preeclampsia or gestational hypertension had the highest future risk. Surprisingly, the researchers found that women whose blood pressure rose sharply in the first 20 weeks had an increased risk of hypertension later, even if they didn’t develop high blood pressure during their pregnancy. It turned out that the rate of change in blood pressure was as important as the actual blood pressure reached. This means even among women who had no pregnancy-related blood pressure issues, those with a sharp rise in blood pressure during the first 20 weeks was a sign of future cardiovascular concerns.
Women with high or rising blood pressure trajectories patterns were up to 11 times more likely to develop hypertension later on compared to those with the most stable, low readings. In fact, the risk ranged from nearly three times to over 27 times higher, depending on both the blood pressure pattern and whether the woman had complications during pregnancy.
Looking Ahead: A New Role for Prenatal Care
This study adds a new layer to how we understand pregnancy and long-term heart health. It shows that blood pressure patterns during just the first 20 weeks of pregnancy long before labor or delivery can quietly reveal a woman’s future risk of chronic hypertension. This risk exists even in women who never develop conditions like preeclampsia or gestational hypertension.
With this knowledge, early blood pressure checks during pregnancy could do more than protect mothers and babies in the short term, they could also offer a window into future heart health. By identifying women at higher risk early on, doctors may one day offer more targeted follow-up care, helping to prevent or delay the onset of chronic hypertension later in life. Pregnancy may only last nine months, but the clues it offers could last a lifetime
References
Roberts JM, Alexeeff SE, Sun B, et al. Early Pregnancy Blood Pressure Trajectories and Hypertension Years After Pregnancy. Hypertension. 0(0). doi:10.1161/HYPERTENSIONAHA.125.24649