Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
darimi:966Abū al-Nuʿmān > Abū ʿAwānah > Abū Bishr > Mujāhid And Mā Taghīḍ al-Arḥām al-Rʿd 8 > Idhā Ḥāḍat al-Marʾah Wahī Ḥāmil

[Machine] About Mujahid, "And (the) wombs do not lessen (the value)" [Ar-Ra'd: 8], he said, "When a woman menstruates while pregnant," he said, "It will result in a decrease in the child. But when it exceeds nine months, it will complete what was decreased from her child."  

الدارمي:٩٦٦أَخْبَرَنَا أَبُو النُّعْمَانِ حَدَّثَنَا أَبُو عَوَانَةَ عَنْ أَبِي بِشْرٍ

عَنْ مُجَاهِدٍ {وَمَا تَغِيضُ الْأَرْحَامُ} [الرعد 8] قَالَ «إِذَا حَاضَتِ الْمَرْأَةُ وَهِيَ حَامِلٌ» قَالَ «يَكُونُ ذَلِكَ نُقْصَانًا مِنَ الْوَلَدِ فَإِذَا زَادَتْ عَلَى تِسْعَةِ أَشْهُرٍ كَانَ تَمَامًا لِمَا نَقَصَ مِنْ وَلَدِهَا»