expression, godan verb (-su)
become pregnant with an illegitimate child
A fixed, somewhat old-fashioned expression literally meaning 'to harbor the seed of karma'. It refers specifically to becoming pregnant out of wedlock, often with a nuance of moral judgment or unfortunate circumstances.
昔の小説では、因果の胤を宿した娘がよく登場する。
In old novels, a girl who has become pregnant with an illegitimate child often appears.
A neutral, standard verb meaning 'to become pregnant'. Unlike 因果の胤を宿す, it carries no implication of illegitimacy or moral judgment.
The expression combines 因果 (karma, fate) and 胤を宿す (to conceive a child), suggesting that the pregnancy is a result of past misdeeds or an unfortunate destiny. The exact historical origin is uncertain, but it reflects traditional views on illegitimacy.