Diaphragmatic Function in Late-Onset FGR Insights From Ultrasound-Based Quantification: Insights from Ultrasound-Based Quantification.

Objectives: We aimed to investigate diaphragm functions via ultrasonography in fetuses with late-onset fetal growth restriction (LO-FGR) and to examine the relationship of these parameters with composite adverse perinatal outcomes (CAPO).

Methods: This prospective cohort study included 40 fetuses with LO-FGR and 40 healthy controls matched for gestational age. Diaphragmatic functions were evaluated using ultrasonography by measuring diaphragm thickness (DT) during inspiration and expiration, diaphragm thickness fraction (DTF), diaphragm excursion (DE), and costophrenic angle (CPA). CAPO was defined as a 5-minute Apgar score of less than 7 and/or infant respiratory complications or admission to the neonatal intensive care unit (NICU). The LO-FGR group was categorized into 2 subgroups: those with CAPO and those without. Statistical analyses evaluated the association between sonographic measurements of the diaphragm and CAPO.

Results: In the LO-FGR group, DT (both inspiratory and expiratory), DTF, DE, and expiratory CPA were markedly reduced (P < .001). In LO-FGR cases that developed CAPO, DT (both inspiratory and expiratory), DTF, and DE were significantly lower (P < .001). Inspiratory DT exhibited the best predictive value for CAPO (area under the curve [AUC]: 0.923), followed by expiratory DT (AUC: 0.865) and DE (AUC: 0.786). Additionally, DUS parameters exhibited better predictive capability relative to Doppler measurements.

Conclusion: Diaphragmatic ultrasonography-derived functional parameters serve as clinically relevant biomarkers for predicting unfavorable perinatal outcomes in LO-FGR. The incorporation of DUS into standard prenatal assessment procedures may enhance the monitoring and management of LO-FGR cases.