Researchers at NYU and partners within the International Healthy Outcomes of Pregnancy for Everyone (HOPE) Consortium have developed a novel tool, the Preterm Birth Actionable Risk Index (PTB-ARIx), designed to identify pregnant individuals at high risk for having a preterm birth (PTB, or delivery before 37 weeks).
By focusing on risk factors for PTB with known, evidence-based treatments—such as using low-dose aspirin to prevent preeclampsia, a life-threatening pregnancy complication marked by high blood pressure—the tool provides a potential pathway to link risk assessment directly to timely medical interventions.
"Our goal is to move from reacting to preterm birth to preventing it by providing families and healthcare professionals with knowledge that they can act upon," said Laura Jelliffe-Pawlowski, professor and senior associate dean of research at NYU Rory Meyers College of Nursing who led the research.
The researchers present their findings on the PTB-ARIx at the annual meeting of the HOPE Consortium today, November 17, coinciding with World Prematurity Day.
The urgent need: rising rates and persistent gaps
Babies born prematurely are more likely to experience a range of health problems, and PTB is the leading cause of child mortality around the world. In the US, more than 350,000 babies are born prematurely each year, driving annual healthcare costs exceeding $25 billion.
Despite decades of research, the US PTB rate (for singleton births, not twins or other multiples) rose from 8 percent to 8.7 percent between 2016 and 2023. This crisis is compounded by two major issues:
Rising risk factors: The increase in PTB mirrors sharp upticks in maternal risk factors, including hypertension, diabetes, asthma, sexually transmitted infections, and mental health conditions. For example, a recent NYU-led study found that the rates of preexisting diabetes, sexually transmitted infections, and mental health conditions more than doubled from 2011 to 2022, and national CDC data show that rates of gestational hypertension in Black individuals rose more than 60 percent between 2016 and 2023, regardless of insurance status.
The "know-do" gap: Many maternal risk factors can be effectively treated, which can help mitigate the risk of PTB—for instance, taking aspirin to prevent preeclampsia, using an inhaler for asthma, taking iron for anemia, or treating infections with antibiotics. However, these treatments are often underutilized, with some studies finding that only 57 percent of those at high risk for preeclampsia received low-dose aspirin and just 32 percent of those with asthma receiving inhalers or medications.
Moreover, treatment is unequal across groups, with studies showing that Black individuals are less than half as likely to receive mental health treatment during pregnancy as their White counterparts (19.1 percent vs. 40.7 percent).
"The consistently low uptake of interventions known to improve maternal health and reduce preterm birth risk represents a critical missed opportunity, particularly in populations already experiencing health inequities," said Jelliffe-Pawlowski. "The PTB-ARIx is designed to bridge this 'know-do' gap by ensuring risk identification is rooted in action."
Translating risk to action
To better quantify these risks and close the treatment gap, Jelliffe-Pawlowski and her collaborators developed the PTB-ARIx using data from 1.9 million live (singleton) births in California from 2016 to 2020. The index focuses on 18 specific risk factors during the first and second trimesters that can be treated with evidence-based interventions, spanning clinical (e.g., preeclampsia, diabetes, anemia, asthma, infections), behavioral (e.g., smoking, substance use), and social (e.g., food insecurity, housing instability) factors.
By inputting and weighing these risk factors, the index calculates a score (0 to 3+) to assess the risk of each pregnancy.
In studying the PTB-ARIx, the researchers found:
Strong prediction for the most serious cases: The tool was highly accurate in flagging individuals at risk for very early preterm birth (before 32 weeks) and showed outstanding accuracy in predicting early PTB when combined with preeclampsia.
High score = high risk: For individuals that scored high (≥3) on the PTB-ARIx, more than 70 percent resulted in preterm birth or another serious adverse outcome, such as having a low-birth-weight baby. Moreover, for every increase of one point in the PTB-ARIx score, the risk of PTB rose by more than 60 percent.
Preeclampsia as a strong predictor: The single greatest risk factor linked to PTB was having preeclampsia risk factors. Individuals with this risk were 6.7 times more likely to experience PTB.
Importance of prenatal care: Regular prenatal visits appeared to play a role in mitigating PTB risk for those with higher scores.
Consistent and equitable across groups: The tool worked reliably across all racial and and ethnic groups studied, as well as across insurance coverage.
"This index offers a critical opportunity to improve patient-provider communication and increase the timely use of evidence-based, preventive care," Jelliffe-Pawlowski added.
The researchers are continuing to study the PTB-ARIx to integrate the index with treatment data and confirm its potential to reduce overall PTB rates. Jelliffe-Pawlowski and her collaborators at the University of Alabama are also working to develop a blood test to measure signals from the body's immune system during early pregnancy as another measure to screen for PTB risk in combination with the PTB-ARIx.
Ultimately, Jelliffe-Pawlowski's goal is to develop a digital platform that empowers providers and patients to work together to better identify pregnancies at risk for PTB and reduce premature births that can be prevented through proactive prenatal care.
In addition to Jelliffe-Pawlowski, the PTB-ARIx research team includes Audrey Lyndon of NYU Rory Meyers College of Nursing; Dana Gossett, Justin Brandt, and Sasha Hernandez at NYU Grossman School of Medicine; and investigators at UC San Francisco, UC San Diego, University of Michigan, UCLA, California State University Northridge, Medical College of Wisconsin, University of Iowa, Indiana University, University of Illinois Urbana-Champaign, and University of Alabama.
