The Vedas say that women menstruate as they took a portion of Indra's sin for killing a brahmin. Didn't women menstruate before this happened? How did they give birth before this happened?
In Rig Veda elimination of Vritra by Indra was mentioned .
According to the Rig Veda, Vritra kept the waters of the world captive until he was killed by Indra. Tvashtra fashioned the thunderbolt (Vajrayudha) for Indra. Thereafter, he defeated Danu, the mother of Vritra.
In Puranas it was narrated that Tvaṣṭā, created Vṛtra to exact his revenge. And, Indra eliminated even Vṛtra.
Rig Veda pre-dates Yajur veda and Puranas. So this episode of elimination of Viśvarūpa and Vritra of from Puranas might be an interpolated one.
There was no mention about killing of Viśvarūpa in Rig Veda. Further, in Rig Veda mention about Danu, mother of Vritra was made.
It indicates that women used to menstruate and procreate even before that episode.
Women menstruated before they partook Indra's sin.
Women were never "cursed" with menstruation according to Samhitas and Brahmana, which are the only authentic portion of the Vedas.
Even in the most quoted verses from the Taittirya Samhita, the women were not cursed. The plain meaning of the text-only leads to the fact that the women accepted the sins of Indra. This is not equivalent to getting cursed!
The Vedas have accorded a respectable position to the women.
Menstruation was not considered as a taboo.
This practices of considering women as impure has no basis in the Saṃhitā and Brāhmaṇa. It is an element of Śramaṇa that was later ingrained in lifestyles to establish superiority over Buddhism.
The Vedic rituals comprise of domestic (Gṛhya) and solemn rituals (Śrauta) which invite the Gods to receive the offerings. The presence of the wife is indispensable in these rituals because God did not accept the oblations offered by an unmarried man. The energy of the women was essential to the rituals and cannot be dispensed with even by the Vedic ritualists (see Śatapatha Brāhmaṇa 188.8.131.52).
अथ पत्नीः संयाजयन्ति । यज्ञाद्वै प्रजाः प्रजायन्ते यज्ञात्प्रजायमाना मिथुनात्प्रजायन्ते मिथुनात्प्रजायमाना अन्ततो यज्ञस्य प्रजायन्ते
तदेना एतदन्ततो यज्ञस्य मिथुनात्प्रजननात्प्रजनयति तस्मान्मिथुनात्प्रजननादन्ततो यज्ञस्येमाः प्रजाः प्रजायन्ते तस्मात्पत्नीः संयाजयन्ति - १.९.२.
Aitareya Brāhmaṇa even goes to the extent of saying that the man cannot become a spiritual entity without a wife. Taittrīya Brāhmaṇa has considered an unmarried person as irreverent (184.108.40.206)!
अयज्ञो वा एषः । योऽपत्नीकः
The hymns of Samāveda were sung by the women who were trained in the music (see Pāṇinīya Śikṣa 5.52).
मन्त्रो हीनः स्वरतो वर्णतो वा मिथ्याप्रयुक्तो न तमर्थमाह।
स वाग्वज्रो यजमानं हिनस्ति यथेन्द्रशत्रुः स्वरतोऽपराधात्।।52।।
In the absence of men, the Vedic scriptures allow the wife to assume the ritual role and she was considered on par with God (see Śatapatha Brāhmaṇa 220.127.116.11 – 4).
पुरुषो वै यज्ञः । पुरुषस्तेन यज्ञो यदेनं पुरुषस्तनुत एष वै तायमानो यावानेव पुरुषस्तावान्विधीयते तस्मात्पुरुषो यज्ञः शिर
एवास्य हविर्धानम् । वैष्णवं देवतयाथ यदस्मिन्त्सोमो भवति हविर्वै देवानां सोमस्तस्माद्धविर्धानं नाम मुखमेवास्याहवनीयः । स
यदाहवनीये जुहोति यथा मुखऽआसिञ्चेदेवं तत् स्तुप एवास्य यूपः । बाहू एवास्याग्नीध्रीयश्च मार्जालीयश्च
It is true that during the period of menstruation the woman cannot serve alone as a medium to transport the powers from the deities see Śatapatha Brāhmaṇa 18.104.22.168).
अथ नेष्टा पत्नीमुदानेष्यन् । कौशं वासः परिधापयति कौशं वा चण्डातकमन्तरं दीक्षितवसनाज्जघनार्धो वा एष यज्ञस्य यत्पत्नी
तामेतत्प्राचीं यज्ञं प्रसादयिष्यन्भवत्यस्ति वै पत्न्या अमेध्यं यदवाचीनं नाभेर्मेध्या वै दर्भास्तद्यदेवास्या अमेध्यं तदेवास्या
एतद्दर्भैर्मेध्यं कृत्वाथैनां प्राचीं यज्ञं प्रसादयति तस्मान्नेष्टा पत्नीमुदानेस्यन्कौशं वासः परिधापयति कौशं वा चण्डातकमन्तरं
दीक्षितवसनात् - ५.२.१.
However, there is no stigma attached to entering the kitchen or the cooking area. This is a later invention to subjugate the women!
Even the performers of the yajñá did not exclude the wife during the period of menstruation from the rituals that were to be performed at the time of the new moon and full moon. The waist of the wife was circumferentially tied with the rope explicitly identified as the noose of Varuṇa (see Śatapatha Brāhmaṇa 22.214.171.124 and 126.96.36.199) and she took part in the rituals even during menstruation.
अथाज्यमादाय प्राङुदाहरति । तदाहवनीयेऽधिश्रयति यस्याहवनीये हवींषि श्रपयन्ति सर्वो मे यज्ञ आहवनीये शृतोऽसदित्यथ
यदमुत्राग्रेऽधिश्रयति पत्नीं ह्यवकाशयिष्यन्भवति न हि तदवकल्पते यत्सामि प्रत्यग्घरेत्पत्नीमवकाशयिष्यामीत्यथ यत्पत्नीं
नावकाशयेदन्तरियाद्ध यज्ञात्पत्नीं तथो ह यज्ञात्पत्नीं नान्तरेति तस्मादु सार्धमेव विलाप्य प्रागुदाहरत्यवकाश्य पत्नीं यस्यो पत्नी न
भवत्यग्र एव तस्याहवनीयेऽधिश्रयति तत्तत आदत्ते तदन्तर्वेद्यासादयति
It is due to these elements of the Vedic religion and probably to stop the high jacking of Śramaṇism on the Vedic way of life, the authors of the Smṛtis of were forced to pronounce that women are always pure (Yājñavalkya Smṛti 1.71, Vaśiṣṭha Smṛti 28.6).
सोमः शौचं ददावासां गन्धर्वश्च शुभां गिरम् ।
पावकः सर्वमेध्यत्वं मेध्या वै योषितो ह्यतः । । १.७१ । ।
Women, Child and old are never impure (Āpastamba Smṛti 2.1 –3). Vaśiṣṭha eulogizing the women even went to compare the acts of women to that of an innocent child and therefore, always pure (see Vaśiṣṭha Smṛti 3.66).
Shankha in his Smṛti has gone proclaimed that as menstruation clears all the sins of the women and she is again purified. (see Sankha Smriti 16-17). Even the most popular Smṛti of Manava (Manu) has said that the mouth of the women and of a bird are pure (see M. Sm. 5.130).
नित्यं आस्यं शुचि स्त्रीणां शकुनिः फलपातने ।
प्रस्रवे च शुचिर्वत्सः श्वा मृगग्रहणे शुचिः ।
Parāśara asks us to do undoable when he exhorts that women are always pure whether they speak pleasantly or unpleasantly. Somā, Gandharva and Agni have purified the women (see Parāśara Smṛti 6.61-63).
कुर्याद्वाक्यं द्विजानां तु अन्यथा भ्रूणहा भवेत् । ब्राह्मणा जङ्गमं तीर्थं तीर्थभूता हि साधवः ।। ६.६१ ।।
तेदां वाक्योदकेनैव शुध्यन्ति मलिना जनाः ।ब्राह्मणा यानि भाषन्ते मन्यन्ते तानि देवताः ।। ६.६२ ।।
सर्वदेवमयो विप्रो न तद्वचनं अन्यथा ।उपवासो व्रतं चैव स्नानं तीर्थं जपस्तपः ।। ६.६३ ।।
Atrī in his Smṛti has even dealt the theme of rape of women and has said without mincing any words that if a woman is raped then such a woman should not be considered fallen and she should not be abandoned.
In conclusion, a woman has been accorded a highly respectable position in the Vedic religion of Samhitā and Brāhmaṇa. It is the moral duty of any sane minded believer in Vedas to emancipate from the mythology of Purāṇa and metamorphize to put claim to the true religion of the Vedas.
There is no permission from the Vedas for nonsensical acts of sending one’s own wife to a forest (because of unfounded suspicion) or stealing the cloths of maidens (for fun or alibis like to fulfil their desires from previous lives).