- A baby is preterm if born before 37 weeks of gestational age.
- Preterm births can be caused by health conditions in the birthing parent and can lead to developmental complications in babies.
- Asian and Pacific Islander mothers saw the largest preterm birth increase. Black and Native mothers’ preterm birth rates remained highest.
- Meanwhile, southeastern states and Puerto Rico saw some of the highest rates of preterm births.
Preterm births last year reached their highest peak since 2007 – with more than 380,000 born before 37 weeks of gestational age in the United States, according to a new report.
In 2021, roughly 10.5% of U.S. babies were born premature, according to the annual March of Dimes “Report Card,” which rated the United States at D+. The score dropped from its C- rating in 2020, when the preterm birth rate saw its first decline in six years, a slight decrease to 10.1%.
The report released this week found disparities widened between white mothers and Native and Black mothers, who are already 62% more likely to have a preterm birth and nearly three times as likely as white moms to die of childbirth-related causes. In 2021, Black mothers saw a 3% increase and Native mothers a 6% increase in preterm births, according to the analysis.
Of all groups, Asian and Pacific Islander mothers saw the largest preterm birth increase – an 8% surge – even though births to Asian mothers decreased that year, and they have the lowest preterm birth rate overall.
Experts say the COVID-19 pandemic may have contributed significantly to the rising preterm birth rates, and the findings signal a need for more efforts toward ensuring equitable prenatal care access.
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What is premature birth? What causes preterm labor?
Preterm births can be caused by various health conditions in the birthing parent, like high blood pressure and diabetes, as well as stress, problems with the uterus or placenta, infection or inflammation.
Being born premature can lead to significant developmental complications in babies, including undeveloped respiratory systems causing breathing problems, and hearing, vision and behavioral issues.
Pregnant people who contract COVID-19 are 40% more likely to go into preterm labor, said Dr. Zsakeba Henderson, an obstetrician and gynecologist who is the March of Dimes’ senior vice president and interim chief medical and health officer.
Additionally, lockdowns and changes or delays in care during the pandemic may have caused gaps in prenatal care, which Black and Native mothers already suffered disproportionately, noted Henderson, who leads the nonprofit’s Office of Maternal and Child Health Impact.
Where in the US are preterm births most common?
Only four states saw a decrease in preterm births, and 45 states and Washington, D.C., saw an increase, according to the analysis by the March of Dimes, a maternal and infant health research and advocacy nonprofit.
Southeastern states, as well as Puerto Rico, saw some of the highest rates of preterm births. The report also showed states with some of the lowest maternal and infant health scores were in the South, a region plagued by structural racism where more than half of the nation’s Black population lives.
“I don’t think that’s a coincidence. Consistently, the worst rates have been seen in that region,” Henderson said. “These states have large populations of Black mothers who experienced the highest rates.”
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‘Not doing enough’
Infant mortality rates decreased slightly overall, but disparities remained, with Black babies dying at 10.8 per 1,000 births, Native babies at 8.4 per 1,000 births, and Hispanic babies at 5 per 1,000 births. White babies saw 4.6 deaths per 1,000 births.
The trends are “disturbing,” said Dr. Cynthia Gyamfi-Bannerman, who is chair and professor of obstetrics, gynecology and reproductive sciences at the University of California, San Diego.
“It shows that we are not doing enough. It suggests we are moving in the wrong direction in terms of solutions,” said the physician, who is a specialist in maternal-fetal medicine and high-risk pregnancies. “Any increase in preterm birth is concerning because of the downstream effects on the infant after a preterm delivery.”
Despite “decades of research” on preterm births, the increase “highlights that fact that we have very few reliable interventions to prevent preterm delivery,” she added.
Rise in Asian American preterm births
While the increase in Asian preterm births was stark, they remained a small percentage of the overall increase, Henderson said. Black and American Indian mothers still had the highest rates, the report found.
“We don’t know the cause for that increase (in Asian mothers),” she said. “That’s something worth looking into for further investigation and paying attention to as we continue to follow these trends.”
Still, experts say multiple factors could have contributed. Asian American mothers are having their first babies at an older age, which can increase risk of preterm labor.
“Asian American women have the oldest average age of first-time motherhood, and it is also associated with preterm birth,” said Deepa Dongarwar, a data scientist at the University of Texas Health Science Center who studies Asian American maternal and infant health. “That actually puts the infant at a very big risk.”
Additionally, Dongarwar noted Asian Americans have been found to use infertility treatments at higher rates compared to other groups. These treatments “are also associated with increased risk of multiple pregnancies, which in turn is associated with preterm birth,” she explained.
Dr. Yvonne Cheng, a maternal-fetal medicine specialist with Sutter Pacific Medical Foundation in San Francisco, called the rise “disappointing and concerning.” Asian communities suffered specific stressors during the pandemic, she noted.
“At the beginning of the pandemic, the unknown surrounding the COVID-19 virus and its effect on pregnancy created a lot of fear, stress and also anger toward and within the Asian American communities,” she said.
Asian communities are also diverse. Further analyses into different groups can help inform where needs are, experts said. One study by Dongarwar found U.S. Filipina and Vietnamese mothers had increased odds of preterm birth compared with East Asian mothers.
Cheng said COVID-19’s social isolation could have decreased access to prenatal care and contributed to preterm delivery.
“Pre-existing medical or obstetric conditions such as diabetes, hypertension and multiple births are significant contributing factors,” she said. “But we cannot ignore other factors … inadequate prenatal care, psychosocial stress, delayed child-bearing.”
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Reach Nada Hassanein at [email protected] or on Twitter @nhassanein_.