It is a pejorative term that makes reference to surrogacy. Although it is commonly used, especially in the Internet in womb-for-rent ads, we do not recommend it to be used in any context.
There is no such a thing as a womb for rent—a womb or uterus is not a materialistic thing or an object that can be hired our or rented as if it was a house or a car, for example. When a woman becomes a surrogate, she helps someone else have a baby by "lending" her ability to bear a pregnancy to term.