Srimad-Bhagavatam: Canto 6 - Chapter 1 - Verse 53

Sanskrit:

स्त्रियो वीरवतीश्चार्चेत्स्रग्गन्धबलिमण्डनै: ।पतिं चार्च्योपतिष्ठेत ध्यायेत्कोष्ठगतं च तम् ॥ ५३ ॥

ITRANS:

striyo vīravatīś cārcetsrag-gandha-bali-maṇḍanaiḥpatiṁ cārcyopatiṣṭhetadhyāyet koṣṭha-gataṁ ca tam

Translation:

With flower garlands, sandalwood pulp, ornaments and other paraphernalia, a woman following this vow should worship women who have sons and whose husbands are living. The pregnant wife should worship her husband and offer him prayers. She should meditate upon him, thinking that he is situated in her womb.

Purport:

The child in the womb is a part of the husband’s body. Therefore the husband, through his representative, indirectly remains within the womb of his pregnant wife.