怀 + (Aspect/Modifier) + 孕
孕 (yùn) is the noun component of the separable verb 怀孕 (to be pregnant), meaning "pregnancy" or "gestation." When 怀孕 is separated, 孕 retains its meaning and can take modifiers or aspect markers between it and 怀. Understanding this separation is key to using the verb naturally in various grammatical structures.
她怀了孕之后就辞职了。
Tā huái le yùn zhīhòu jiù cízhí le.
She quit her job after she got pregnant.
她怀过两次孕,生了一儿一女。
Tā huái guò liǎng cì yùn, shēng le yì ér yì nǚ.
She was pregnant twice and had a son and a daughter.
她怀着孕还每天跑步,真厉害。
Tā huái zhe yùn hái měitiān pǎobù, zhēn lìhai.
She still runs every day while pregnant — that's really impressive.