만삭(滿朔) means "the last month of prenancy." Synonyms for 만삭 include 해산달 and 당삭. The word also means "the first day of a lunar month (초하루), which is when the moon appears as a crescent. The bulging belly of a woman in her last month of prenancy looks a lot like a crescent moon, which is probably why the same word is used to describe a new moon and a pregnant women.
In a September 28, 2007 article HERE, 만삭 was used to describe the figure of a pregnant Christina Aguilar (크리스티나 아길레라 만삭 몸매 "내 몸에 키스" 화제!!); however, the article said that the baby was not due until December, which means that Ms. Aquilar was not yet in her last month of pregnancy. The writer of the article misused the word 만삭.
Here is the picture that was posted with the article: