New study reveals growing disparities in preterm birth rates

Preterm births have increased by more than 10 percent in the past decade, with racial and socioeconomic disparities remaining over time, according to a new study analyzing more than five million births.

The study, published in the journal JAMA Network Openalso found that some factors that increase the risk of preterm birth—such as diabetes, sexually transmitted infections, and mental health conditions—have become much more common over the past decade, while other factors that protect against preterm birth have declined.

“Our findings not only show that preterm births are increasing, they provide clues Why that may be happening,” said Laura Jelliffe-Pawlowski, the study’s lead author, an epidemiologist and professor at NYU Rory Meyers College of Nursing and emeritus professor of epidemiology, biostatistics and global health sciences at the University of California, San Francisco. (UCSF) School of Medicine “Understanding the patterns and factors associated with preterm birth is important for informing clinical care and developing public health programs to address this critical need.”

Babies born preterm or preterm—before the 37th week of pregnancy—are more likely to experience a range of short- and long-term problems, including a higher risk of illness, mental and emotional difficulties, and death. Certain factors are known to increase the risk of preterm birth, including mothers with high blood pressure, diabetes, infection, or smoking. In addition, black, Native American, and Hawaiian and Pacific Islander expectant mothers are at higher risk for preterm birth, which is believed to be due to a long history of structural racism experienced by these groups.

To understand recent trends around preterm births, Jelliffe-Pawlowski and her colleagues looked at more than 5.4 million singleton births (not twins or other multiples) from 2011 to 2022 in the state of California. They examined how preterm birth rates changed over time and explored patterns of risk and protective factors within racial/ethnic and socioeconomic groups. Type of health insurance was used as a proxy for socioeconomic status, comparing public insurance (MediCal, California’s Medicaid program) with nonpublic insurance (including private insurance and coverage through the military and the Indian Health Service).

A growing danger and “alarm bells”

The researchers found that preterm births increased 10.6 percent over the decade studied, from 6.8 percent in 2011 to 7.5 percent in 2022—mirroring a report from the Centers for Disease Control and Prevention ( CDC) released earlier this year, which also found an increase in preterm birth across the country from 2014 to 2022.

Preterm birth rates increased in almost all groups, but varied by race/ethnicity and socioeconomic group. The highest rates of preterm birth were among black mothers with public insurance (11.3 percent), while the lowest rates were among white mothers who had no public insurance (5.8 percent). Preterm birth rates declined slightly over time among black mothers with no public insurance, from 9.1 percent in 2011 to 8.8 percent in 2022, but were still significantly higher than rates among white mothers. In contrast, preterm birth rates increased from 6.4% to 9.5% among Native American mothers with no public insurance.

“We found stark differences in what it looks like to be a pregnant black or Native American compared to a middle- or higher-income white person.”

Laura Jelliffe-Pawlowski, lead author of the study

Extending the findings of the CDC report by examining risk and protective factors over time, the researchers found that several factors were associated with an increased risk of preterm birth, including diabetes, high blood pressure, prior preterm birth, fewer than three prenatal visits care and housing insecurity. Specifically, rates of pre-existing diabetes, sexually transmitted infections and mental health conditions more than doubled during the decade studied.

“These patterns and changes in risk factors should raise alarm bells,” Jelliffe-Pawlowski said.

Several factors were found to protect against preterm birth in low-income expectant mothers, including prenatal care and participation in WIC, the supplemental nutrition program that supports women and children. Unfortunately, the researchers observed a decline in WIC participation in most low-income racial/ethnic groups during the period studied.

What can be done to improve birth outcomes?

The researchers note that their findings highlight the need to improve pregnancy care and promote treatments that address risk factors associated with preterm birth, which are often underutilized during pregnancy, especially in mothers of color.

“We need to do a better job of sharing information with pregnant women about risk factors for preterm birth and interventions that may help them address that risk. Some providers report that they don’t want to scare or overwhelm pregnant women, but pregnant women tend to to report who wants to have that information,” Jelliffe-Pawlowski said. “For those at increased risk due to factors such as hypertension or previous prematurity delivery, for example, providers should discuss how taking low-dose aspirin can be helpful for them and their growing baby.This extends to topics such as screening for sexually transmitted infections and providing mental health care health in a non-judgmental, supportive way”.

“There is also significant work to be done to improve structural issues and respectful care in WIC to increase participation,” Jelliffe-Pawlowski added.

Jelliffe-Pawlowski and her colleagues are also working to develop a digital platform called Hello Egg to help expectant mothers better understand their risk of preterm birth, identify interventions that may help them, and create a healthy pregnancy program that co-developed with prenatal providers. . Jelliffe-Pawlowski and her start-up team, EGG Healthy Pregnancy, aim to conduct a large study to see if using the platform enhances a pregnant woman’s knowledge. A key outcome will be to see if this sharing of information leads to increased use of interventions and, ultimately, reduced risk of preterm birth and other adverse outcomes.

The research was supported by the University of California, San Francisco California, Preterm Birth Initiative. Additional authors of the study include Audrey Lyndon of NYU Meyers and colleagues from the University of California, San Francisco. University of California San Diego; Stanford University? UCLA Medical Center; California State University, Northridge; San Francisco State University? Indiana University Bloomington; University of Alabama at Birmingham? and the University of Illinois Urbana-Champaign.