娠

Phono-semantic compound:

女 (“woman”) provides the semantic component.

辰 (“star, time, morning”) provides the phonetic value.

Thus, the character conveys the idea of a woman (女) in a special condition of time (辰) – pregnancy.

임신 (妊娠) — pregnancy

태신 (胎娠) — gestation, being pregnant

Unlike 妊 (“to conceive, be pregnant”), 娠 is more technical/medical in usage, often appearing in compound words such as 妊娠.