The type of cell that must contain a mutation in order for it to be passed from a woman to her offspring is a germ cell.

Here's why:

* Germ cells are the cells that give rise to sperm and egg cells (gametes). These are the cells involved in sexual reproduction.

* Somatic cells are all the other cells in the body (like skin cells, muscle cells, etc.). Mutations in somatic cells are not passed down to offspring.

Therefore, a mutation must occur in a germ cell (egg cell in this case) for it to be passed down to the woman's offspring.