Hanafi
The sources give no view for it here.
نكاح من لم يولد بعد
هل يحل نكاح من لم يولد بعد؟
Each school’s answer
In our wordsHanafi
Not stated in the sources
Maliki
Not stated in the sources
Shafi'i
Not stated in the sources
Hanbali
Not stated in the sources
The texts
١٨٧٨ - مَسْأَلَةٌ: وَلَا يَحِلُّ نِكَاحُ مَنْ لَمْ يُولَدْ بَعْدُ، فَمَنْ فَعَلَ ذَلِكَ لَمْ يَلْزَمْهُ، لِأَنَّهُ لَا يَدْرِي أَيُولَدُ لَهُ ابْنَةٌ، أَمْ ابْنٌ، أَمْ مَيْتَةٌ. [مَسْأَلَةٌ لَا يَحِلُّ نِكَاحُ غَائِبَةٍ إلَّا بِتَوْكِيلٍ مِنْهَا عَلَى ذَلِكَ]
From the schools’ own books
Maliki
The sources give no view for it here.
Shafi'i
The sources give no view for it here.
Hanbali
The sources give no view for it here.
What is «in our words» is our standard wording; the books’ texts stay as they are.