Figure 2.

Schematic overview of placenta collection at delivery. Samples from the placenta will be collected for analysis of histology, DNA, RNA, proteins, metabolomics, fatty acids, toxicants and essential elements. First four pieces, 4 cm³ of villous tissue including decidua will be collected from the basal plate from four separate places of the placenta. The decidua will be removed stored in a separate cryo-tube. The remaining villous tissue will be divided into 20 smaller pieces, 4 pieces of 3 mm Ø that will be put in RNAlater and 16 pieces that will be put 4 and 4 in separate cryo-tubes. Two different cross-sections will be then collected: one cross-section measuring approximately 2×2 cm taken within 4 cm from the cord insert will be placed in formalin. Another cross-section formed as a V taken from the cord insert to the end of the placenta will be sampled with specific metal-free ceramic knife and put into plastic bags. The cross-sections will be taken with care to avoid selecting a tissue section that has previously been sampled for villous tissues. At 1 cm from the cord insert, a 2 cm piece of the umbilical cord will be sampled and stored in formalin. From the same end of the cord, two pieces, 1 cm each in length, will be sampled and placed in a cryo-tube. Also, samples from the membrane will be collected: pieces of the amnion and chorion membranes will be placed in separate cryo-tubes, while one piece of membrane with both the membranes still attached to each other (‘double membrane’) will be placed in formalin.