Birth control has some detail to it. Therefore, I say that this thing, which has come to be known as "birth control" is from that which the Muslims of today are being tested by in the lands of Islaam. However, there are cases from it, which must be referred back to the motive behind it. An example of this is when the motive for this birth control is based on a prescription from Muslim doctors who are advising the couple towards this so-called "birth control" to safeguard the health of the woman who has departed from her natural state due to her having delivered many children! So if a skilled Muslim doctor issues these instructions as a form of advice, then that becomes a legitimate excuse for (the allowance of) this birth control.
This is an example in which birth control is permissible. As for an example that is contrary to this one, then it is such as when the motive behind it is due to poverty (!) or because of bills, which is always on the minds of the disbelievers!! So you can see one of them say: "My wife and I are two. And I have two children!! And the fifth member of them is their dog!! So this monthly pay that we receive is just enough for us (to pay our bills), and that's all [five]!" This is not permissible in Islaam because this motive emanates from the logic of the Days of Ignorance, which we were warned to avoid and stay away from. Such is found in Allaah's saying: "And do not kill your children for fear of poverty. We will provide you with sustenance as well as them." [Surah Al-Ana’aam: 151]
This is especially the case since the Muslims believe that the child comes with his sustenance (already) with him. This is because, before it comes out into this world, its sustenance is ordained for it while it is in the womb of its mother, as has been clarified to us in the Noble Sunnah. So this example of birth control, with this motive, is not permissible at all. As for the baseless and false reasons that some people have used to justify and allow it, then they have no place in the Religion.