What is the ruling on artificial insemination using an ovum from the first wife and implanting it in the womb of the second wife?

This type of insemination is forbidden by Sharia (definition) and falls under the five categories that the Islamic Fiqh Council (Majma' al-Fiqh al-Islami) declared unlawful in its third session in 1986 CE, due to the resulting mixing of lineages and loss of motherhood. As for the permissible methods, they are those in which insemination occurs between the spouses, whether externally, where the zygote is then implanted in the wife's womb, or internally, by injecting the husband's sperm into his wife's womb.