The Compendium of Caraka 4.8.40

4.8.40

tāścaināṃ yathoktaguṇāḥ striyo 'anuśiṣyuḥ---anāgatāvīrmā pravāhiṣṭhāḥ; yā hyanāgatāvīḥ pravāhate vyarthamevāsyāstat karma bhavati, prajā cāsyā vikṛtā vikṛtimāpannā ca, śvāsakāsaśoṣaplīhaprasaktā vā bhavati/

And those women possessing the aforementioned qualities should instruct her: 'Do not bear down in the absence of labor pains; for she who bears down in the absence of labor pains—her effort becomes entirely futile, and her offspring becomes impaired, suffers deformity, or becomes afflicted with dyspnea, cough, consumption, or splenic disorder.'