✅Answer: Please pay attention to the following verse and narrations:

وَيَسْأَلُونَكَ عَنِ الْمَحِيضِ قُلْ هُوَ أَذًى فَاعْتَزِلُوا النِّسَاءَ فِي الْمَحِيضِ وَلَا تَقْرَبُوهُنَّ حَتَّى يَطْهُرْنَ

And they ask you about menstruation. Say: It is a harm and discomfort. So, keep away from (sexual intercourse with) women during their menstruation and do not approach them until they are purified!

1 قال أَبُوعَبْداللَّه الْمَرْأَةُ تَحِيضُ يَحْرُمُ عَلَى زَوْجِهَا أَنْ يَأْتِيَهَا في فَرجها لِقَوْلِ اللَّهِ تَعَالَى وَ لا تَقْرَبُوهُنَّ حَتَّى يَطْهُرْنَ فَيَسْتَقِيمُ لِلرَّجُلِ أَنْ يَأْتِيَ امْرَأَتَهُ وَ هِيَ حَائِضٌ فِيمَا دُونَ الْفَرْج

📚 Tafsir Ayyashi, Vol. 1, p. 110

Imam Sadiq (prayers of Allah be upon him) said: When a woman is menstruating, it is forbidden for her husband to have intercourse with her in her private part because of the saying of Allah the Most High (Surah Al-Baqarah, verse 222) where He says: 'do not approach them until they are purified.' And it is permissible for a man to approach his menstruating wife in other than her private part!

2 عبداللَّه بْنِ سنانٍ عَنْ أَبِي عَبْداللَّه فِي الْمُسْتَحَاضَةِ إِلَى أَنْ قَالَ وَ لَا بَأْسَ أَنْ يَأْتِيَهَا بَعْلُهَا إِذَا شَاءَ إِلَّا أَيَّامَ حَيْضِهَا فَيَعْتَزِلُهَا زَوْجُهَا

📚 Al-Kafi, Vol. 3, p. 90

Imam Sadiq (prayers of Allah be upon him) said about a woman with irregular bleeding: There is no problem if her husband wants to have intercourse with her, except during her menstruation, when her husband keeps away from (intercourse in her private part) with her!

3 قال الصَّادِقُ لَا يُبْغِضُنَا إِلَّا مَنْ خَبُثَتْ وِلَادَتُهُ أَوْ حَمَلَتْ بِهِ أُمُّهُ فِي حَيْضِهَا

📚 Al-Faqih, Vol. 1, p. 96

Imam Sadiq (prayers of Allah be upon him) said: No one hates us except for one whose birth is impure or whose mother conceived him during her menstruation!

4 معاوية بن عمار عن أبي عبداللَّه قال: سَأَلْتُهُ عَنِ الْحَائِضِ مَا يَحِلُّ لِزَوْجِهَا مِنْهَا قَالَ مَا دُونَ الْفَرْج

📚 Al-Kafi, Vol. 5, p. 538

Muawiyah ibn Ammar said: I asked Imam Sadiq (prayers of Allah be upon him) about a menstruating woman, what is permissible for her husband from her? He said: Whatever is other than the private part!

4 علي بن يقطین عن أَبي الحسن موسى بْنِ جَعْفَر قَالَ: سَأَلْتُهُ عَنِ الْحَائِضِ تَرَى الطُّهْرَ أَ يَقَعُ بِهَا زَوْجُهَا قَبْلَ أَنْ تَغْتَسِلَ قَالَ لَا بَأْسَ وَ بَعْدَ الْغُسْلِ أَحَبُّ إِلَيَّ

📚 Al-Tahdhib, Vol. 1, p. 167

Ali ibn Yaqtin said: I asked Imam Kadhim (prayers of Allah be upon him) about a menstruating woman who becomes pure, should her husband have intercourse with her before she performs ghusl (ritual bath)? He said: There is no problem, and after ghusl is more beloved to me!

6 داود بن فرقد عن أَبِي عَبْداللَّه فِي كَفَّارَةِ الطَّمْثِ أَنَّهُ يَتَصَدَّقُ إذَا كَانَ في أَوَّلِهِ بِدِينَارٍ و فِي وَسَطِهِ نِصْفِ دِينَارٍ وَ فِي آخِرِهِ رُبُعِ دِينَارٍ قُلْتُ فَإِنْ لَمْ يَكُنْ عِنْدَهُ مَا يُكَفِّرُ قَالَ فَلْيَتَصَدَّقْ عَلَى مِسْكِينٍ وَاحِدٍ وَ إِلَّا اسْتَغْفَرَ اللَّهَ و لَا يَعُودُ فَإِنَّ الِاسْتِغْفَارَ تَوْبَةٌ و كَفَّارَةٌ لِكُلِّ مَنْ لَمْ يَجِدِ السَّبِيلَ إِلَى شَيْءٍ مِنَ الْكَفَّارَة

📚 Al-Tahdhib, Vol. 1, p. 164

Imam Sadiq (prayers of Allah be upon him) said about the expiation for (intercourse) during menstruation: If it is in the beginning of the menstruation, he gives one dinar in charity, in the middle of it half a dinar, and at the end of it one-fourth of a dinar. I said: What if he has nothing for expiation? He said: He should give charity to a needy person, and if not, he should ask for forgiveness and not return to this act again, and indeed, asking for forgiveness is repentance and expiation for anyone who has no way to a form of expiation!

✅ Based on verse 222 of Surah Al-Baqarah and numerous narrations, intercourse in the private part during menstruation is forbidden. However, the use of other than the private part is permissible according to the narrations. If a man, God forbid, commits this forbidden act, in addition to various dangers such as becoming an enemy of the Ahl al-Bayt (peace be upon them) and the resulting child having a repulsive appearance, leprosy, or being afflicted with vitiligo, which are mentioned in the narrations, he is obligated to give an expiation. If this act occurs in the first third of menstruation, he must give one gold dinar (a gold coin equivalent to about 4.265 grams) as charity to the poor and needy; if in the second third, half a gold dinar; and if in the last third, one-fourth of a dinar. If he cannot, he should give some charity to a needy person, and if not, he should seek forgiveness and repent.

✅ However, when the woman becomes pure from menstruation, permission for intercourse before the ghusl of menstruation has been mentioned, but it is recommended to be after the ghusl.

✅ The few hadiths that indicate there is no need for expiation in the case of intercourse during menstruation, in addition to being against precaution, are also in agreement with Abu Hanifa, Malik, and Shafi'i, and they are not to be acted upon due to their agreement with the majority of the public and being against precaution.