Increased Incidence of Hypertensive Disorders of Pregnancy in Young Americans

Hypertensive disorders of pregnancy (HDP), which include preeclampsia, eclampsia and hypertension, are the leading causes of mortality and morbidity in pregnant women. As a result, HDP has become a significant health crisis among pregnant women in the United States.

Recent data indicate that HDP is an important risk factor for cardiovascular disease. HDP has been shown to increase the risk of heart failure two to four times in pregnant women.

Study: Association of year of birth of pregnant people with trends in hypertensive disorders of pregnancy in the United States, 1995-2019. Image Credit: Compoo Suriyo /


Over the past decade, HDP levels have nearly doubled to 8% of pregnant women. The highest incidence of HDP has been reported among non-Hispanic American Indians, non-Hispanic blacks, and Alaska Natives.

Although the age of pregnant women when they first give birth is a risk factor for HDP, a recent study has shown that women of all ages are increasingly affected by this condition. This observation strongly indicates that factors other than age contribute to the incidence of HDP.

A recent Open JAMA Network The study performed an age-period-cohort analysis to investigate the independent relationship between pregnant women’s age at delivery, pregnant women’s year of birth (cohort), and delivery year (period) with the appearance of HDP in nulliparae.

About the study

A total of 38,771,194 nulliparous people aged 15-44 years were identified between 1995 and 2019. People without sufficient relevant data on PDH and pre-pregnancy hypertension were excluded from the cohort.

Finally, 38,141,561 people were included, of which 20.2% were Hispanic, 6.5% non-Hispanic Asian or Pacific Islander, 0.8% non-Hispanic Native American or Alaskan Native, 57.8% non-Hispanic white and 13.9% non-Hispanic black.

Study results

Cohort analysis revealed that the incidence of recent-onset HDP was higher in pregnant women who were older at the time of delivery, in more recent periods, and in more recent birth years of pregnant women. . Compared to nulliparous pregnant women born in the 1950s, those born in the 1990s and 2000s had a higher incidence of HDP, even after adjusting for age at delivery.

Persistent occurrence of HDP, regardless of age, birth cohort, and delivery period, has been observed in self-identified non-Hispanic American Indians or Alaska Natives and non-Blacks. hispanics. Additionally, a significant increase in the incidence of HDP in these groups has been reported from 2010 to 2019.

The study results add to previously published data by establishing an independent relationship between a birth cohort of pregnant women and the incidence of HDP in nulliparous women in the United States between 1995 and 2019.

Although the present study did not identify the factors responsible for the incidence of HDP in younger pregnant women, it did highlight some possible contributing factors.

For example, pregnant women with a history of cardiovascular disease were at increased risk of developing HDP. This factor also increased mortality and morbidity rates, as well as the risk of cardiovascular health problems for the offspring. Cohort analysis also revealed a trend for greater occurrence of new HDPs in older, non-Caucasian pregnant women during childbirth.

A previous study on high blood sugar and adverse pregnancy outcomes reported that people with a cardiovascular condition at an average gestational age of 28 weeks are nine times more likely to develop preeclampsia than those without cardiovascular disease.

Among cardiovascular health-related issues, the incidence of obesity increased significantly from 6.2% between 1976-1980 to 32.7% between 2017-2018. However, the population attributable fraction for HDP associated with obesity did not change significantly between 2011 and 2019. This suggests that obesity could partially contribute to the incidence of HDP.

Further research using pregnancy-specific cohorts with long-term follow-up is needed to better understand the association between obesity and HDP.

Study limitations

The potential misdiagnosis of recent onset of HDP from National Vital Statistics System (NVSS) records was noted. However, due to the inclusion of people with preeclampsia and gestational hypertension, the issues associated with the HDP definition change have been triaged.

As the study is ecological in nature, potential risk factors for HDP were not identified.


High levels of HDP in young pregnant women of more recent generations have increased the urgency to develop effective strategies to prevent adverse clinical outcomes. Studies such as the current one have made practitioners aware of the prevalence of HDP in younger generations to ensure that appropriate preventive measures are advised.

Early assessment of cardiovascular health and initiation of effective treatments before a person’s first pregnancy could be an effective strategy to reduce the incidence of HDP.

Multidisciplinary experts, including primary care physicians, obstetrician-gynecologists, and cardiologists, must work together to develop strategies for optimal management of HDP risk factors before, during, and after pregnancy.

Journal reference:

  • Cameron, NA, Petito, LC, Shah, NS, et al. (2022) Association of year of birth of pregnant people with trends in hypertensive disorders of pregnancy in the United States, 1995-2019. Open JAMA Network 5(8). doi:10.1001/jamanetworkopen.2022.28093

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