"Big with child" is a somewhat archaic phrase that is often used to describe a woman who is heavily pregnant or in her later stages of pregnancy. Some alternative synonyms that could be used in place of this phrase include "heavy with child," "great with child," or "ripe with child." Additional phrases that are commonly used to describe a woman in this stage of pregnancy include "expecting," "pregnant," "with child," "in the family way," and "with a bun in the oven." These phrases are more commonly used in modern language and can replace the more outdated phrasing of "big with child".