Śrīmad-Bhāgavatam · Text 3.31.5
Who is speaking and story frame
मातुर्जग्धान्नपानाद्यैरेधद्धातुरसम्मते ।
शेते विण्मूत्रयोर्गर्ते स जन्तुर्जन्तुसम्भवे ॥ ५ ॥
mātur jagdhānna-pānādyair
edhad-dhātur asammate
śete viṇ-mūtrayor garte
sa jantur jantu-sambhave
Deriving its nutrition from the food and drink taken by the mother, the fetus grows and remains in that abominable residence of stools and urine, which is the breeding place of all kinds of worms.
Read Śrīla Prabhupāda's purport on Vedabase.io