The ductus arteriosus in the neonatal period

Doppler flow characteristics in the main pulmonary artery and the $$\overline {LA} /Ao$$ ratio before and after ductal closure in healthy newborns/Ao ratio before and after ductal closure in healthy newborns

“…The consent of the parents was obtained . The first examination was carried out within 18 hours after birth ; the second on the second day, the third on the third day, and the last In the lower half the time interval histogram [14] . In between, the electrocardiogram .…”

“…Up to now, determining the exact time of closure of the ductus arteriosus has been very difficult . So far data have been obtained from autopsy [7,14], heart catheterization [16,19], dye curve [18], and auscultation [6] . Closure times of the ductus, estimated by these techniques, vary from 10 hours to several weeks after birth .…”

Persistent Ductus Arteriosus in Ill and Premature Babies

“…Anatomical closure of the human ductus arteriosus may occur from a few days to a few months after birth, but occurs by the age of 4 weeks in the great majority of cases (Christie, 1930;Jager and Wollenman, 1942;Mitchell, 1957;Wilson, 1958) and is preceded by functional closure which occurs from a few hours to a few days after birth (Eldridge and Hultgren, 1955;Adams and Lind, 1957;Burnard, 1958Burnard, , 1959Braudo and Rowe, 1961;Moss, Emmanouilides and Duffie, 1963). The factors which precipitate closure, or which may delay it, are only partly understood, but prematurity, birth asphyxia, and the respiratory distress syndrome have been thought to delay or prevent it.…”

The Changes in the Circulation After Birth

“…In normal mature infants, the duetus is permanently closed within 2 to 3 weeks after birth. 42 W\7e hav7e previously reported delayed closure of the ductus arteriosus in several preniature infants. 43 No information is available regarding the size of the ductus arteriosus in fetuses or in infants at the time of birth in whom pulmonary or tricuspid atresia is present.…”