Maternal Sociodemographic Factors, Adiposity, and Pregnancy Outcomes Among Preterm Deliveries Admitted to the Neonatal Intensive Care Unit.

Introduction: Preterm birth represents about 10% of all births in the United States and is known to be influenced by maternal factors, including pre-pregnancy adiposity, measured using BMI. Pre-pregnancy adiposity is influenced by environmental and sociodemographic factors. This exploratory analysis aimed to explore the complex relationship between pre-pregnancy adiposity, sociodemographic factors, and delivery outcomes among preterm deliveries.

Methods: In this retrospective record review study, participants were mothers of infants born before 34 weeks and 6 days gestational age (GA) and admitted to the NICU at Loyola University Medical Center between 2018 and 2020. Maternal data were extracted using EPIC electronic medical record review. We used Chi-square test/Fisher's exact test for categorical variables and Kruskal-Wallis or Mann-Whitney U tests for continuous variables to test for significance across BMI categories. An exploratory multiple linear regression analysis to test the association between gestational age at delivery, obesity/overweight, socioeconomic status, and ethnicity/race was performed and supplemented with permutation testing. Statistical significance was set at p < 0.05.

Results: Among the 27 included participants, the median maternal age was 34 years. The prevalence of pre-pregnancy obesity was 42.9%. Women with obesity/overweight tended to have a lower GA at delivery than women with a normal pre-pregnancy BMI (29.5 weeks vs. 31 weeks, p = 0.073). GA at delivery trended positively with higher socioeconomic status (B = 4.2, 95%CI 1.4-7.0, p = 0.007), and inversely with having overweight/obesity (B=-3.6, 95%CI -5.7- -1.6, p = 0.002), and identifying as non-Hispanic Asian or non-Hispanic Black race/ethnicity (B=-6.3, 95%CI -10.3- -2.4, p = 0.005 and B=-0.50, 95%CI -7.8- -2.2, p = 0.002, respectively).

Discussion: In addition to adiposity, race, ethnicity, and socioeconomic status may be associated with more severe preterm delivery (lower GA). While this exploratory study is limited by the small sample size, our findings highlight the impact of sociodemographic factors on maternal obesity and severity of pregnancy complications in the context of preterm birth with NICU admission.