Maternal antibodies transported across the placenta protect the newborn. Maternal immunoglobulin G (IgG) concentrations in fetal blood increase from early in the second trimester through term, most antibodies being acquired during the third trimester. IgG1 is the most efficiently transported subclass and IgG2 the least. Transfer across the syncytiotrophoblast of the chorionic villi is mediated by the neonatal Fc receptor, FcRn. Immune complexes are absorbed in the stroma of the villi, probably by FcgammaRI, FcgammaRII, and FcgammaRIII on placental macrophages. The mechanism of IgG transport across the endothelium of fetal capillaries is not understood. Endothelial cells in terminal villi express FcgammaRIIb. However, it is not known whether this receptor transports IgG or prevents transport of immune complexes to the fetus.
Pharmacology, Toxicology and Pharmaceutical Science
13
3%
Other
38
9%
Unknown
114
26%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 37. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 01 September 2026.
All research outputs
#1,372,622
of 33,779,198 outputs
Outputs from Vaccine
#1,238
of 19,805 outputs
Outputs of similar age
#1,529
of 75,025 outputs
Outputs of similar age from Vaccine
#5
of 94 outputs
Altmetric has tracked 33,779,198 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 95th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 19,805 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 19.1. This one has done particularly well, scoring higher than 94% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 75,025 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 98% of its contemporaries.
We're also able to compare this research output to 94 others from the same source and published within six weeks on either side of this one. This one has done particularly well, scoring higher than 94% of its contemporaries.
