before week 16 of gestation <8%: between weeks 17 and 22 of gestation 10-20%: by 26 weeks of gestation till delivery 100% % of the average normal adult concentration
||Human Homo sapiens
||Saji F, Samejima Y, Kamiura S, Koyama M. Dynamics of immunoglobulins at the feto-maternal interface. Rev Reprod. 1999 May4(2):81-9 p.81 left column bottom paragraphPubMed ID10357095
||Gitlin D (1971) Development and metabolism of the immunoglobulins. In Immunologic Incompetence pp 3–13 Eds BM Kagan and ER Stiehm. Year Book Medical Publishers, Chicago
||P.81 left column bottom paragraph: "The immunoglobulins in the fetus consist almost totally of maternal IgG and are transferred across the placenta by means of a specific receptor-mediated mechanism. IgG transport from mother to fetus begins at about week 16 of gestation and increases thereafter. Before week 16 of gestation, serum IgG concentrations of the fetus are < 8% of the average normal adult concentration. Between weeks 17 and 22 of gestation, fetal serum IgG concentrations range between approximately 10 and 20% of the adult value, and, after week 22 of gestation increase rapidly, reaching maternal serum IgG concentrations by 26
weeks of gestation and maintaining them until delivery (primary source)."