The following is a summary of “Examining recent trends in spontaneous and iatrogenic preterm birth across race and ethnicity in a large managed care population,” published in the JUNE 2023 issue of Obstetrics and Gynecology by Mensah, et al.

For a study, researchers sought to analyze recent trends in preterm birth (PTB) and its subtypes among singleton births, considering maternal race and ethnicity, using data from electronic health records. Despite various interventions to reduce PTB rates, it remained a significant cause of infant morbidity and mortality in the United States and worldwide. PTB rates have shown an upward trend in epidemiological studies from the United States over several decades.

The study utilized Kaiser Permanente Southern California electronic health records for all singleton births between 2009 and 2020 (n=427,698). PTB trends and subtypes (spontaneous and iatrogenic PTBs) were examined using data on preterm labor triage extracted through natural language processing. Maternal race and ethnicity were categorized as non-Hispanic White, non-Hispanic Black, Hispanic, and non-Hispanic Asian or Pacific Islander. Multiple logistic regression assessed linear trends for PTB and its subtypes, further examining racial and ethnic trends through statistical interactions and stratifications.

Between 2009 and 2020, the overall preterm birth rate in the study decreased by 9.12%, from 8.04% to 7.31% (P<.001). Notably, the rates of preterm birth declined by 19.29% among non-Hispanic Whites, from 7.23% to 5.83% (P<.001), and by 6.15% among Hispanics, from 7.82% to 7.34% (P=.036). Similarly, preterm birth rates decreased by 12.60% among non-Hispanic Asian or Pacific Islanders, from 8.90% to 7.78% (P<.001). However, a non-significant increase of 8.45% in the preterm birth rate was observed among non-Hispanic Blacks, from 9.91% to 10.75% (P=.103). Over the same period, spontaneous preterm birth rates showed a significant decrease of 28.85% across all participants, from 5.75% to 4.09% (P<.001). Among specific racial and ethnic groups, the rates of spontaneous preterm birth also decreased significantly. For instance, non-Hispanic Whites experienced a decline of 34.73%, from 5.44% to 3.55% (P<.001), while non-Hispanic Blacks saw a reduction of 19.75%, from 6.82% to 5.47% (P<.001). Hispanics showed a decrease of 22.96%, from 5.55% to 4.28% (P<.001), and non-Hispanic Asian or Pacific Islanders had a decline of 28.19%, from 6.50% to 4.67% (P<.001). In contrast, iatrogenic preterm birth rates increased significantly by 40.45% overall, from 2.29% to 3.22% (P<.001). This upward trend was observed within each racial and ethnic group, with non-Hispanic Whites experiencing a 52.42% increase, from 1.88% to 2.61% (P<.001). The iatrogenic preterm birth rate for non-Hispanic Blacks surged by 107.89%, from 3.18% to 6.13% (P<.001). Similarly, Hispanics had an increase of 46.88%, from 2.29% to 3.26% (P<.001), and non-Hispanic Asian or Pacific Islanders saw a rise of 42.21%, from 2.45% to 3.44% (P<.001).

The overall PTB rate decreased over time, driven by a decrease in spontaneous PTB rates. Racial and ethnic variations were observed in both spontaneous and iatrogenic PTB rates. The notable increase in iatrogenic PTB, especially among non-Hispanic Blacks, warranted further investigation.

Source: ajog.org/article/S0002-9378(22)02176-7/fulltext