Foetal Cardiac Function in Early Labour and Intrapartum Outcomes: A Prospective Observational Study.

Objective: To assess foetal myocardial deformation in normo-oxygenated foetuses in early labour and its relationship with intrapartum outcomes.

Design: Single centre prospective study.

Setting: Referral tertiary maternity unit.

Population: Uncomplicated singleton term pregnancies in early labour.

Methods: Two-dimensional (2D) ultrasound clips of the 4-chamber view of the foetal heart were collected in labour and sent to TomTec software for the offline speckle tracking echocardiography analysis. The left (LV) and right ventricular (RV) myocardial (MyoGLS) and endocardial longitudinal (EndoGLS) strain were evaluated.

Main Outcome Measures: Operative delivery including caesarean or assisted vaginal birth due to suspected intrapartum foetal compromise (IFC) as defined by standard CTG criteria.

Results: In total, 208 cases were included. Operative delivery due to suspected IFC was recorded in 20 (9.6%) cases and was associated with higher LV ejection fraction (EF) (47.4 + 8.2 vs. 40.9 + 12.9%, p = 0.03) and increased RV MyoGLS (-15.9 + 4.0 vs. -12.5 + 4.3%, p < 0.01) and RV EndoGLS (-17.7 + 4.4 vs. -14.3 + 4.7%, p < 0.01) compared to cases not having operative delivery due to suspected IFC. Maternal age (OR 1.138, 95% CI [1.010-1.281], p = 0.03), baseline foetal heart rate at acquisition (OR 1.068, 95% CI [1.007-1.134], p = 0.03) and RV MyoGLS (OR 0.575, 95% CI [0.366-0.903], p = 0.02) were independently associated with the primary outcome.

Conclusions: Increased right ventricular myocardial deformation is associated with operative delivery due to suspected IFC, suggesting an early cardiac response to labour-related hypoxia.