If the mother's Diyya is paid over three years, how is the fetus's Diyya paid?

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If the ruling is that the mother's Diyya is paid over three years, two possibilities exist for the fetus's Diyya. One possibility is that it is also paid over three years, corresponding to the years the mother's Diyya is paid, meaning one-third of each Diyya is due each year, as they are two distinct entitlements. The alternative possibility is that the fetus's Diyya is paid over three entirely separate years, as the death of the fetus constitutes a single injury obligation.