Matsyapurana 68.14

68.14

saptamīsnapanaṃ vakṣye sarvalokahitāya vai
jātasya mṛtavatsāyāḥ saptame māsi nārada
athavā śuklasaptamyām etatsarvaṃ praśasyate //

I shall now explain to you about the rituals of ablution on the seventh day of a lunar fortnight, in order that all men may be benefited by it. The woman, whose offspring does not survive, ought to bathe on the seventh day of the lunar fortnight, or on the seventh month after the birth of the child.—14.