Pregnancy Complication Rates Doubled in U.S. In Recent Years: Study

High blood pressure and heart disease are seen as possible contributors to increasing pregnancy complication rates in the U.S.

A new study warns that one in five pregnancies in the United States will result in a preterm delivery or a baby with low birth weight, as pregnancy complications have continued to rise nationwide in recent years.

In findings published this month in the Journal of the American Heart Association, researchers warn that heart disease and high blood pressure may be contributing to rising infant and maternal morbidity and mortality rates in the United States, but does not answer why the country ranks virtually last among all modern nations for maternal death rates.

Researchers from Northwestern University in Chicago examined data on 51.6 million live births over the 12-year period between 2007 and 2019, to understand the trends and causes of adverse pregnancy outcomes (APOs), such as pre-term delivery, hypertensive disorders of pregnancy, and low birth weight, which have been steadily increasing across the nation.

Many of the health problems pregnant mothers and their newborns suffer are due to APOs which cause short and long-term physical adversity due to the link between pregnancy complications and an increased risk of heart disease. Cardiovascular disease has been ranked as the leading cause of postpartum maternal mortality and accounts for 26.5% of maternal deaths in the United States.

The study reveals a surge in two types of hypertensive birth disorders: preeclampsia and gestational hypertension. Over the research period, the rates of these illnesses nearly doubled; rising from 38 per every 1000 live U.S. births in 2007 to nearly 78 in every 1000 in 2019.

During the later years of the study, the rate of these complications increased greatly, rising an average of 9.1% a year from 2014 to 2019, compared to 4.1% a year from 2007 to 2014.

Hypertensive birth disorders were cited as one of the leading causes of the recent increases in preterm birth and low birth weight. Mothers suffering from preeclampsia may require early induction, resulting in preterm delivery. Infants delivered early are far more likely to have a low birth weight.

The study also examined the effect of maternal age on the prevalence of APOs and found that, though the average age of women giving birth had risen by roughly 2 years, the increase in maternal age was not having as much of an impact on the rise of APOs as expected. The acceleration of problematic pregnancies proved to be higher among younger women.

Since 1999, the cardiovascular health, rates of obesity, prediabetes, and diabetes of young adults of reproductive age have worsened in the United States and may be a contributing factor to the increased risk of APOs, researchers determined.

The increases in APOs were similar across all age, racial, and ethnic groups, indicating that the historic disparities between black and white mothers have not narrowed. To combat these disparities, the authors of the study suggest that focus be placed on the social determinants of health: the conditions in the environments where people are born, live, learn, work, play, worship, and age that affect a wide range of health, functioning, and quality-of-life outcomes and risks. They also suggested this includes targeting structural and systemic racism and improving access to quality health care following pregnancy.

U.S. maternal mortality rates still exceed every other high‐income country in the world. This fact raises the importance of targeted surveillance and earlier interventions to reduce cardiovascular risk among those who experienced an APO. This all requires access to quality and affordable health care which previous studies on the subject indicate is severely lacking in the United States.