CVS Practice Test

When does complete closure of the ductus venosus take place?

1. Within the first week after birth

2. At 1-3 months

3. At 6 months

4. After one year

The correct answer is: At 1-3 months

The closure of the ductus venosus is a significant physiological change that occurs as part of the transition from fetal to postnatal life. After birth, the ductus venosus, which is a vessel that allows blood to bypass the liver in utero, begins to functionally close soon after the umbilical cord is cut and the newborn starts breathing air. The complete anatomical closure of the ductus venosus usually occurs within a range of 1 to 3 months after birth. This timeframe aligns with the development of the liver and the overall circulatory system as the newborn acclimates to life outside the womb. The process is facilitated by changes in blood flow dynamics and pressure changes that occur following the cessation of placental circulation. The options indicating later timeframes for closure, such as 6 months or after one year, extend beyond the typical physiological adaptation period that happens soon after birth. Therefore, choosing the option that corresponds to the 1-3 months timeframe accurately reflects the standard timing for complete closure of the ductus venosus.