TWIN TO TWIN TRANSFUSION SYNDROME
PLACENTA ANALYSIS PROTOCOL©
The following show the steps through pictures to correctly analyze a monochorionic placenta to confirm twin to twin transfusion syndrome. Below are key points to beginning the analysis:
1. When analyzing a placenta for twin to twin transfusion syndrome, the placenta should be refrigerated before examination, never frozen or fixed. Ideally one has:
a camera to make a picture (and that is recommended) or at
least the facility to draw a picture of the placenta, cords
and blood vessels
a 10 ml syringe with several-sized needles for injection
a small amount of milk
two pairs of tweezers
formalin bottles to receive the samples for histology
(if histology is to be performed)
a board on which to lay the placenta for examination and sectioning
If the placenta cannot be examined locally and must be shipped, it could be done so by FedEx in a cooled styrofoam container. It could also be fixed in formalin, but examination is much more difficult thereafter (not recommended).
2. The report should include:
cord lengths, insertions, and number of vessels
nature of surface blood vessels by inspection and after local milk injection
location and nature (amnions only or amnions and chorions) of the “dividing membranes”
weight of the placenta and size
estimation of the size and proportion of each placental portion for each baby (that is best done after one has identified the final ends of the blood vessels from each half – it is the “vascular equator” that matters).
3. Histology is the preparation of sections and examination under the microscope. Generally it is not needed for the interpretation of twin to twin transfusion syndrome placentas, but it is a good idea anyway.
4. A velamnentous cord is also cord “membranous” insertion. It is one where the cord inserts on the placental membranes, not on the surface of the placenta; in the placental photographs that follow, it was baby “B”. It usually is the donor in twin to twin transfusion syndrome that has the velamentous cord insertion.
5. The twins from the pictured placenta did survive. The donor was 925 g and recipient 1400 g at 26 weeks. The baby girl with the more normal cord insertion was the recipient and first born, hence “A”; the one with velamentous cord thus became “B”.
6. There were some thrombi because the vessels running in the membranes (the “velamentous” vessels) are more prone to being injured, as they do not have the “protection” from Wharton’s jelly in the cord or the softer placental tissue on the fetal surface of the placenta.