Pulmonary hypoplasia in fetuses with congenital conotruncal defects.

CTD is associated with hypoplastic main and branch pulmonary arteries as well as PH. Risk factors for PH included defect types (DORV and TOF but not TGA) and RVOTO. It is plausible that pulmonary blood flow, rather than the type of CTD, RVOTO, or pulmonary artery dimensions, plays a key role in PH.