During pregnancy the womb’s network of blood vessels expands to provide extra nourishment for the growing baby. However, if the mother’s blood supply were to be in direct contact with the baby, her immune system would sense the baby as a ‘foreign invader’ and try to eliminate it. How is the growth of blood vessels controlled to keep the baby safe? Pictured is a pregnant mouse womb with maternal blood vessels (stained red) surrounding an unstained embryo (dark central region). The researchers already knew of a protein that stops blood vessel growth in other regions of the body, and they looked for it in the pregnant womb. They find the protein (stained green) concentrates around the embryo, creating a barrier that prevents the invasion of maternal blood vessels and keeps the developing offspring safe.
Written by Julie Webb
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