Adhyaya 89: शौचाचारलक्षणम् — सदाचार, भैक्ष्यचर्या, प्रायश्चित्त, द्रव्यशुद्धि, आशौच-निर्णय
दशाहं सूतिकाशौचं मातुरप्येवमव्ययाः अर्वाक् त्रिवर्षात्स्नानेन बान्धवानां पितुः सदा
daśāhaṃ sūtikāśaucaṃ māturapyevamavyayāḥ arvāk trivarṣātsnānena bāndhavānāṃ pituḥ sadā
Ритуальная нечистота (āśauca), возникающая при рождении ребёнка, длится десять дней; для матери — так же. Для ребёнка младше трёх лет очищение совершается омовением; и для родни по отцу это следует понимать всегда таким же образом.
Suta Goswami
It sets a dharmic boundary for resuming Shiva-puja after childbirth: observing sutika-āśauca (ten days) and using snāna as the purifier for very young children, so worship of Pati (Shiva) is done with proper niyama.
Indirectly, it implies Shiva as Pati—the ever-pure Lord—while the pashu (bound soul) follows disciplines of purity and restraint to remove pasha (ritual and mental taints) and return to ordered worship.
A purity observance (niyama) centered on āśauca and its cessation, with snāna (ritual bathing) as the key purificatory act—supporting the eligibility to perform Shiva-puja and related rites.