The Compendium of Caraka 4.8.32_1

4.8.32_1

tatra garbhasya keśā jāyamānā māturvidāhaṃ janayantīti striyo bhāṣante; tanneti bhagavānātreyaḥ, kintu garbhotpīḍanādvātapittaśleṣmāṇa uraḥ prāpya vidāhaṃ janayanti, tataḥ kaṇḍūrupajāyate, kaṇḍūmūlā ca kikkisāvāptirbhavati/

In this matter, women say that the hair growing on the embryo causes burning sensations in the mother; the venerable Ātreya says that this is not so: rather, due to compression by the embryo, vāta, pitta, and phlegm reach the chest and produce burning sensations; from that, itching arises; and rooted in itching, the appearance of stretch marks occurs.