The secretion of PAPP-A, ADAM12, and PP13 correlates with the size of the placenta for the first month of pregnancy

ObjectivesPregnancy Associated Protein A (PAPP-A), A Disintegrin and Metalloproteinase 12 (ADAM12) and Placental Protein 13 (PP13) are secreted from the placental trophoblastic tissue and are involved in normal implantation and placental development. The aim of the study was to assess the connection between the secretion of these proteins and the growth of the gestational sac and the placenta.Study designIn an observational longitudinal study at Oulu University Hospital, women with naturally conceived pregnancies were followed-up weekly to pregnancy week 11.Main outcome measuresPAPP-A, ADAM12 and PP13 serum concentrations and their correlation with the volumes of the gestational sac and the placenta were assessed using three-dimensional ultrasonography.ResultsThe study group consisted of 41 women. The PAPP-A, ADAM12 and PP13 serum concentrations increased continuously from pregnancy week 4 to week 11 and correlated closely with each other. The serum concentrations of PAPP-A, ADAM12 and PP13 also correlated with the volumes of the gestational sac and the placenta up to pregnancy week 8.ConclusionsThe secretion of PAPP-A, ADAM12 and PP13 is closely related to the size of the placenta in the beginning of pregnancy. After 8 weeks of pregnancy, which is the time for luteoplacental shift, the correlation disappears, possibly reflecting the morphologic transformation in the placenta.