Folksy/euphemistic — northern colloquial, common in older speech and dialect. Standard equivalents: 怀孕 (huáiyùn 'be pregnant', verb) or 孕妇 (yùnfù 'pregnant woman', clinical noun). 重身子 is warmer but old-fashioned.
memory
Literally 'heavy body' — a pregnant body is carrying extra weight. Note 重 reads zhòng ('heavy') here, NOT chóng ('again').
