Difference in the Iddat of Talaaq and demise

In a period of 4 months 10 days (which is the Iddat of a widow who lost her husband), life enters the fetus (which the widow may be carrying in her womb), hence in this period one is able to ascertain (with a great degree of certainty) whether the widow is pregnant or not.

Secondly, the wife experiences a great deal of grief on losing her husband. Therefore, the Iddat being 4 months and 10 days seems more appropriate for mourning the loss of the husband, whereas the aspect of mourning to this extent is not applicable to a divorced woman.

Thirdly, the Iddat period of a widow that lost her husband is fixed and stipulated in the Quraan Sharif. Therefore, even if we are unaware of the reasoning and wisdom behind the lengthier Iddat for her, we should accept it and not raise objections.