Author Question: Which one of the following weeks of gestation would most interest a health care provider who is ... (Read 27 times)

mp14 · **on:** Jul 23, 2018

Which one of the following weeks of gestation would most interest a health care provider who is concerned about heightened drug transfer via the placenta?

a. 36
b. 24
c. 18
d. 8

Question 2

Which of the following tissues is capable of causing the greatest biotransformation of drugs that cross the placenta and affect the fetus?

a. Liver of the fetus
b. Maternal organs
c. Placenta
d. Umbilical cord

frre432 · **Reply #1 on:** Jul 23, 2018

Answer to Question 1

ANS: A
Drug transfer via the placenta is greatest late in gestation. As pregnancy progresses, chorionic villi become more numerous, providing a greater surface area across which diffusion between the two circulations can occur. Near term, the membrane separating maternal and fetal circulation thins considerably, so that fetal capillary endothelium is separated from maternal circulation by a single layer of fetal chorionic tissue. Inflammation, hypoxia, vascular degeneration, or partial separation of the placenta affects drug transfer just as it affects transfer of oxygen and nutrients to the fe-tus.

Answer to Question 2

ANS: B
Fetal biotransformation of drugs is believed to be minimal. The fetus relies on maternal plasma levels of a drug to clear the drug from the fetal circulation.