We had explored whether Tfap2b was involved in the known prostaglandin pathway by treating pregnant mice at E18.5 with indomethacin, but observed premature closure of the DA in all wild-type and Tfap2b−/− fetuses, suggesting that the PDA in Tfap2b−/− mice was a primary event independent of the prostaglandin pathway. This evidence concerns the gene TFAP2B and Patent ductus arteriosus.