Labor Status at Delivery and Lung Function in Extremely Prematurely Born Young Adults

There has been conflicting evidence regarding the impact of mode of delivery on respiratory outcomes in later childhood and adulthood. It is possible labor status, rather than mode of delivery, influences later respiratory morbidity. We hypothesized that extremely premature infants born to mothers in labor would have better lung function at follow-up than those born to mothers not in labor.

We reviewed data from the United Kingdom High-Frequency Oscillation Study. Lung function testing was performed on young people aged 16-18 years born before 29 weeks of gestation. Linear mixed models were used to adjust lung function for maternal and neonatal factors and for the clustering due to multiple births.

One hundred and fifty subjects underwent lung function testing. Young adults born to mothers in labor had better mean Forced Expiratory Flow₇₅ (FEF₇₅) compared to those born to mothers not in labor (adjusted difference 0.50 [95% CI: 0.02, 0.99]). Similar significant differences were noted in FEF₅₀ (0.45 [-0.05, 0.85]), and FEF_25-75 (0.53 [0.05, 1.01]).

Our study demonstrates that amongst individuals born very prematurely, those whose mothers were in labor before delivery had better small airway function at 16-19 years of age.