Nasa'i 4099 records the canonical framework for fetal blood-money. The framework treats a fetus as having legal-financial value but at a reduced level compared to a born person. Joseph Schacht, An Introduction to Islamic Law (Clarendon Press, 1964), the standard Western reference for classical fiqh, notes that the law of compensation (diyya) is among the most elaborately developed areas of Islamic criminal doctrine, with graduated rules covering not only adults but the unborn. The compensation varies by:

1. Gestational age. Earlier-stage miscarriages receive less compensation than later-stage. 2. Gender. Some classical schools distinguish male and female fetuses, with female fetuses valued less. 3. Viability. After ensoulment (typically at 120 days per the angel-writes-four-things hadith), the fetus is treated as a person and may receive full diyya.

The theological problems:

1. Tiered fetal personhood. The framework establishes that fetuses have graded legal-financial value depending on developmental stage. This is itself an ethical claim about when human life begins to matter morally — and the answer is 'gradually,' not 'at conception.'

2. The 120-day ensoulment. The standard Sunni position is that ensoulment occurs at 120 days (per the angel-writes-four-things hadith — Bukhari 3208; parallel: Muslim 2643). The hadith records that after three forty-day stages (nutfa, 'alaqa, mudgha), the angel is sent to breathe the soul into the embryo and write four things: provision, deeds, lifespan, and fate. Ibn Hajar al-'Asqalani, in his commentary Fath al-Bari (the canonical Arabic commentary on Sahih al-Bukhari), draws on this hadith to establish that voluntary movement and perception — the markers of full moral status — are acquired only after ensoulment. Before ensoulment, the fetus has reduced moral status. This affects abortion ethics in Islamic legal tradition: pre-120-day abortions are often permitted under specific circumstances, post-120-day abortions are generally forbidden.

3. Gender differential. Some classical schools (especially Maliki) value male fetuses higher than female fetuses for diyya purposes. This extends the gender halving (entry d05) to the fetal stage, creating the most extreme intersectional reduction: female fetuses at the lowest legal-financial value. Rudolph Peters, Crime and Punishment in Islamic Law: Theory and Practice from the Sixteenth to the Twenty-First Century (Cambridge University Press, 2005), the leading modern survey of Islamic criminal law in practice, documents how diyya rules — including differentiated compensation rates — remained operative in Ottoman courts and modern Muslim-majority states well into the contemporary period.

4. The ghurra payment. The classical compensation is a 'ghurra' — typically a slave girl or boy of specified value. Malik ibn Anas preserves the earliest systematic ruling in the Muwatta, Book 43, Hadith 6 (Blood-Money), where the Prophet's judgment in a case involving a woman of the Hudhayl tribe is recorded: a stone thrown at a pregnant woman caused a miscarriage, and the ruling was that the diyya for the fetus is a ghurra — a slave or slave-girl of fair complexion and excellence. This ruling is preserved through Abu Hurayra via Ibn Shihab. This is itself problematic: the compensation for human life lost is paid in the form of another human (slave). The framework treats some humans (slaves) as currency for compensating for the loss of other humans (fetuses).

5. Modern application. Modern Saudi Arabia, Iran, and other Muslim-majority states have applied versions of fetal-diyya rules. Peters (2005) documents that the frameworks have been adapted — typically converting ghurra into monetary equivalents — but generally preserve the principle of tiered fetal personhood.

6. Comparison with modern medical ethics. Modern bioethics generally treats personhood as developing through gestation (with various positions on when full moral status applies). The Islamic framework's specifics — 120-day ensoulment, gender differential, ghurra-payment — are pre-modern and reflect 7th-century legal-medical understanding.

7. The internal Muslim divergence. Sunni and Shia jurisprudence vary on fetal diyya specifics. The fragmentation reflects the framework's contested nature.