All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
According to the view that we consider to be the most preponderant at Islamweb, aborting the fetus is not permissible, even if the fetus is at the Nutfah stage (mixed drop of the male and female water).
Ad-Dardeer said in his commentary on Khaleel, “It is not permissible to remove the semen from the womb, even before forty days. If the soul is breathed into the fetus, then it is prohibited by the consensus of the scholars.”
Therefore, if you did not have a valid excuse for carrying out this abortion, then both you and your husband must hasten to repent. To learn about the conditions of repentance, please refer to fatwa 86527.
If you are the one who carried out the abortion without your husband, then you are the one obliged to pay the Diyah of the fetus, and your husband, though he is sinful for sharing in the decision, is not obliged to pay part of the Diyah as he is not the one who carried out the abortion.
The Fiqh Encyclopedia reads:
“There is no difference of opinion among the scholars that directly transgressing against others is one of the strongest causes that renders one a guarantor (i.e. responsible for paying the Diyah). They also agreed that, in general, if the one who carried out the action and the one who caused it both agreed (to take the action), then the ruling applies to the one who carried out the action, though they (the scholars) differed on some details. The rule is: If the cause and the actual undertaking are combined, or deceit and undertaking are combined, then the undertaking comes first.”
There is a difference of opinion among scholars regarding the obligation of expiation, but in order to be on the safe side, it is better to expiate, as we have already highlighted in fatwa 128722.
Your non-Muslim relatives have no share in this Diyah, as there is no inheritance between a Muslim and a non-Muslim due to the hadeeth by Usaamah ibn Zayd in which the Prophet said, “A Muslim does not inherit from a non-Muslim, and a non-Muslim does not inherit from a Muslim.” [Al-Bukhari and Muslim]
Your Muslim sister is the maternal aunt for your child, so she is one of its Thawul Arhaam (relatives who are related to it through one or more female links); and Thawul Arhaam – according to the scholars who are of the view that they inherit – do not inherit except if there is no other heir who has an allotted share or who inherits by Ta’seeb (by virtue of having a paternal relation with the deceased and not having an allotted share, so they get what is left after the allotted shares have been distributed).
For more benefit, please refer to fataawa 85558 and 102388.
Allaah knows best.