Is Rural Residence an Independent Risk Factor for Spontaneous Preterm Birth at a Midwestern Tertiary Care Center? A Cross-Sectional Study.

OBJECTIVE

Assess whether maternal rural residence was an independent risk factor (RF) for spontaneous preterm birth (sPTB) at a Midwest tertiary care center.

METHODS

After excluding deliveries complicated by indications for induced preterm birth, there were 16 974 deliveries among 13 339 women between May 1, 2009, and May 31, 2023. Standard descriptive statistics and Generalized Linear Mixed Models were used to identify RFs for sPTB.

RESULTS

Of the 16 974 deliveries, 89.1% were full term, 28.8% were of rural mothers, and the mean maternal age was 29.6 years (y). 15.5% of rural deliveries were sPTBs versus only 9.1% of urban deliveries (P<.001). Significant independent RFs for sPTB included the extremes of maternal age (aOR, 2.14 for age 14 to <20 y and aOR, 3.37 for age ≥40 y) compared to age 20-<30 y, rural vs. urban residence (aOR, 1.56), maternal smoking (aOR, 2.47), transfer from an outside hospital (aOR, 671.3), and female sex of the baby (aOR, 0.79). With the transferred deliveries excluded these factors remained significant with similar aORs and Asian race was an additional significant protective factor (aOR, 0.57). Body mass index, race, ethnicity, type of medical insurance, and primigravidity were not significant RFs.

CONCLUSION

Rural residence, extremes of maternal age, maternal smoking, female newborn sex, and transfer from an outside hospital were significant and independent RFs for sPTB.