K E Y W O R D S:congenital diaphragmatic hernia; fetal lung; lung-to-head ratio; peak early-diastolic reversed flow; pulsed Doppler ABSTRACT Objectives To describe the association between the intrapulmonary circulation and the degree of lung growth in fetuses with congenital diaphragmatic hernia (CDH). Methods Thirty-six fetuses with isolated left CDH at 22-29 weeks of gestation were studied. Four groups were defined according to lung-to-head ratio (LHR), expressed as the ratio of observed to expected LHR for gestational age (O/E LHR). Pulsatility index (PI), peak systolic velocity (PSV), peak early-diastolic reversed flow (PEDRF), end-diastolic velocity (EDV), acceleration time (AT), time averaged velocity (TAV) and the ratio AT to ejection time (AT/ET) were measured in all fetuses in the proximal arterial branch of both lungs. For analysis, Doppler values were converted to Z-scores. Results It was possible to record all Doppler parameters from the contralateral lung of all CDH fetuses, and from the ipsilateral lung in 28 (77.7%). PEDRF significantly increased in relation to the decrease in O/E LHR in both lungs

Objective To assess the learning curve for the fetal lung area to head circumference ratio (LHR) calculation in fetuses with congenital diaphragmatic hernia (CDH). Methods