Allah said,

﴿وَإِن كُنَّ أُوْلَـتِ حَمْلٍ فَأَنفِقُواْ عَلَيْهِنَّ حَتَّى يَضَعْنَ حَمْلَهُنَّ﴾

(And if they are pregnant, then spend on them till they lay down their burden.) This is about the woman who is irrevocably divorced. If she is pregnant, then she is to be spent on her until she lays down her burden. This is supported due to the fact that if she is revocably divorced, the she has then right to receive her support (maintenance) whether she is pregnant or not.