Abnormalities of lung volume at follow-up after antenatal rhesus iso-immunization

Rhesus iso-immunization is associated with fatal pulmonary hypoplasia. We have examined the hypothesis that abnormalities of lung volume, as an index of lung growth, may also be found in survivors. At a median age of nine months, lung volume was assessed by measurement of functional residual capacity in 23 patients affected antenatally by rhesus iso-immunization. Seventeen of the patients had required at least one intrauterine transfusion. Five patients (group A) had an FRC < 24 ml/kg (median 21 ml/kg, range 19-22 ml/kg) and the other 18 (group B) an FRC > or = 24 ml/kg (median 27 ml/kg, range 24-36 ml/kg) (p < 0.01). The only significant difference between these two groups was the timing of the first foetal blood sampling and intrauterine transfusion, being a median of 22 weeks (range 20-23 weeks) in group A and 30 weeks (range 17-36 weeks) in group B (p < 0.01).