A new study has found that some women who maintain blood pressure levels within the clinically normal range during pregnancy may still be at significantly higher risk of developing high blood pressure within five years of giving birth—especially if their blood pressure does not drop during the second trimester, as is typical in healthy pregnancies.
The research, published in the Journal of the American College of Cardiology: Advances, shows that about 12% of pregnant women fall into this overlooked risk category.
These women would not be flagged under current medical guidelines, as their blood pressure remains below the standard thresholds for concern. Yet, their risk of developing chronic hypertension after pregnancy was found to be nearly five times higher than women whose blood pressure followed the expected healthy pattern.
What the Study Found
Researchers followed 854 women from pregnancy through five years postpartum, using data from the MADRES cohort—a long-term health study involving primarily low-income Hispanic women in Los Angeles.
The team tracked blood pressure measurements, along with demographic, lifestyle, and health data collected periodically during pregnancy and annually after birth.
They identified three key blood pressure patterns:
- Low and steady blood pressure throughout pregnancy (80.2% of women)
- High early blood pressure that dipped in mid-pregnancy and then rose again (7.4%)
- Slightly elevated but stable blood pressure with no mid-pregnancy dip (12.4%)
Women in the second group—those with high early pregnancy blood pressure and a second-trimester dip—were already known to be high-risk. Many of them developed complications such as preeclampsia or gestational hypertension during pregnancy. They faced a 5.44 times higher risk of developing hypertension in the years after giving birth.
But the surprising discovery was in the third group, whose blood pressure stayed slightly elevated yet still within normal limits, and did not drop in mid-pregnancy. These women had no typical warning signs during pregnancy, but their risk of future hypertension was almost as high—4.91 times greater than the group with consistently low blood pressure.
A Missed Warning Sign?
“This group of women would not be identified as high-risk using today’s clinical criteria,” said Dr. Shohreh Farzan, senior author and associate professor at USC’s Keck School of Medicine. “Their blood pressure looked normal on paper, but the pattern of not having that expected mid-pregnancy drop was the red flag.”
This finding is important because current blood pressure guidelines during pregnancy focus mainly on identifying hypertension or dangerously high readings. They don’t account for patterns of change—particularly the normal physiological drop that typically occurs in the second trimester due to hormonal shifts and increased blood flow.
Dr. Zhongzheng (Jason) Niu, the study’s lead author, noted that this is one of the first major studies to look at blood pressure risk between pregnancy and menopause—a critical but under-researched time in women’s health.
“This period has been a blind spot in cardiovascular research,” Niu said. “Our work helps fill that gap and shows that early signs of trouble can appear much earlier than previously thought.”
Clinical and Public Health Implications
The study suggests that tracking blood pressure trends—not just single readings—during pregnancy could help doctors identify women at risk for long-term heart issues, even if their readings never cross into the “high” category. This could lead to early interventions, such as closer monitoring after birth, lifestyle counseling, or preventive treatments.
Given the growing awareness of women’s heart health, and the American Heart Association’s efforts to refine its guidelines, this research may lead to new standards for prenatal care that could help prevent chronic hypertension and related cardiovascular problems later in life.
The team is also investigating whether environmental exposures—such as air pollution or chemicals like PFAS—might contribute to these unusual blood pressure patterns. If so, it could add an important public health layer to future pregnancy care and disease prevention.
Review and Analysis
This study provides an important message: “normal” blood pressure during pregnancy isn’t always a sign of low risk. By focusing on blood pressure patterns—especially the expected mid-pregnancy dip—doctors may be able to detect a group of women who are quietly at higher risk for developing long-term hypertension.
The findings are especially significant for women of color and those from underserved communities, who are more likely to face healthcare barriers and may already be at higher risk of cardiovascular disease.
As simple tools like blood pressure tracking apps become more widely available, it may soon be possible for expectant mothers and clinicians to monitor these patterns more closely, empowering more personalized and proactive care.
In short, this research challenges the assumption that “normal” always means “safe”—and provides a powerful opportunity to detect and prevent disease earlier in women’s lives.
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The research findings can be found in JACC: Advances.
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