Transplacental nutrient transfer in the human in vivo determined by 4 vessel sampling.

BACKGROUND: The intrauterine environment and especially the fetal nutritional conditions affect lifelong health. There are few human in vivo studies on fetal nutrition. The importance to test experimentally based concepts of fetal nutrition in a human in vivo setting is becoming increasingly apparent. A way of testing nutrient transfer in human is 4-vessel sampling, which implies blood sampling from artery and vein on both sides of the placenta. Here we give a brief review of the studies using the 4-vessel sampling method.

METHOD: We performed systematic searches in Ovid MEDLINE and EMBASE (Ovid) from 1946 to May 2016. The following search terms were used to identify eligible articles: [placenta] AND [glucose/blood glucose] OR [amino acids] OR [lipids] OR [cholesterol] OR [nutrient] AND [blood sample] OR [biological transport] OR [transport/transfer/exchange] OR [maternal-fetal exchange] AND [humans].

RESULTS: The search retrieved 623 studies. After abstract scanning 25 full text articles were evaluated and seven articles describing 4-vessel sampling were identified. The studies had from 14 to 77 participants and reported placental transfer of different nutrients (glucose, lactate, amino acids and arachidonic acid).

CONCLUSION: Few studies have used 4 vessel sampling to study placental nutrient transfer in human pregnancies. Overall these studies indicate that the transfer of nutrients between the mother and the fetus is highly "dynamic," i.e. most nutrients may pass either way on both the maternal and fetal sides of the placenta. Furthermore, the concept that the placenta is a metabolically highly active organ affecting transfer of glucose, amino acids and lipids, fits the human in vivo data. The 4-vessel method can provide essential information on the transfer between the mother, placenta and fetus of virtually any compound.