Srimad-Bhagavatam: Canto 6 - Chapter 1 - Verse 9

Sanskrit:

शश्वत्कामवरेणांहस्तुरीयं जगृहु: स्त्रिय: ।रजोरूपेण तास्वंहो मासि मासि प्रद‍ृश्यते ॥ ९ ॥

ITRANS:

śaśvat-kāma-vareṇāṁhasturīyaṁ jagṛhuḥ striyaḥrajo-rūpeṇa tāsv aṁhomāsi māsi pradṛśyate

Translation:

In return for Lord Indra’s benediction that they would be able to enjoy lusty desires continuously, even during pregnancy for as long as sex is not injurious to the embryo, women accepted one fourth of the sinful reactions. As a result of those reactions, women manifest the signs of menstruation every month.

Purport:

Women as a class are very lusty, and apparently their continuous lusty desires are never satisfied. In return for Lord Indra’s benediction that there would be no cessation to their lusty desires, women accepted one fourth of the sinful reactions for killing a brāhmaṇa.