What is the ruling regarding the sale of a pregnant mortgaged slave whose debt has matured?

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If the debt matures while the female slave is pregnant, she cannot be sold because she is pregnant with the creditor's child. After giving birth, she cannot be sold until she has nursed the child with colostrum (lab'u). If a wet nurse is found, she may be sold; otherwise, she must remain until she nurses the child, after which only enough of her value to cover the debt is sold. The remainder acquires the status of 'Umm Walad' (mother of the master's child), and upon the pledgor's death, she is freed.