Prenatal prediction of pulmonary hypoplasia: clinical, biometric, and Doppler velocity correlates.

OBJECTIVES

To determine the value of pulmonary artery Doppler velocimetry relative to fetal biometric indices and clinical correlates in the prenatal prediction of lethal lung hypoplasia (LH) in prolonged (>1 week) oligohydramnios.

METHODS

Forty-two singleton pregnancies with oligohydramnios associated with premature rupture of membranes ([PROM]; n = 31) or bilateral renal pathology (n = 11) were examined using color-coded Doppler ultrasound in a cross-sectional study design. Mean gestational age was 28.0 +/- 4.3 weeks (range: 20-36 weeks). Thoracic, cardiac, and abdominal circumference and the largest vertical amniotic fluid pocket were measured. Pulsed Doppler measurements of the arterial pulmonary branches were made at the level of the cardiac 4-chamber view. Diagnosis of LH was based on clinical, radiologic, and pathologic criteria. Clinicians were blinded to the prenatal measurements.

RESULTS

The prevalence of lethal LH was 43%. In the PROM subset, combination of onset of PROM at <or =20 weeks, duration of oligohydramnios at > or =8 weeks, and degree of oligohydramnios at < or =1 cm presented the highest clinical prediction rate for lethal LH. For both the total group and the PROM subset, the highest prediction rate for lethal LH was presented by thoracic circumference/abdominal circumference ratio, peak systolic velocity in the proximal branch, and time-averaged and end-diastolic velocity in the middle branch of the pulmonary artery. In the PROM subset, the combination of all 3 clinical, biometric, and Doppler parameters revealed the most favorable combination to predict lethal LH (positive predictive value: 100%; accuracy: 93%; and sensitivity: 71%).

CONCLUSION

Doppler velocimetry may detect changes in pulmonary artery waveforms in the presence of LH but fails to be the ultimate test for the prenatal prediction of lethal LH. The best prediction can be achieved by combining clinical, biometric, and Doppler parameters.